text:
Transcranial magnetic stimulation: Improved coil design for deep brain investigation
NASA Astrophysics Data System (ADS)
This paper reports on a design for a coil for transcranial magnetic stimulation. The design shows potential for improving the penetration depth of the magnetic field, allowing stimulation of subcortical structures within the brain. The magnetic and induced electric fields in the human head have been calculated with finite element electromagnetic modeling software and compared with empirical measurements. Results show that the coil design used gives improved penetration depth, but also indicates the likelihood of stimulation of additional tissue resulting from the spatial distribution of the magnetic field.
Crowther, L. J.; Marketos, P.; Williams, P. I.; Melikhov, Y.; Jiles, D. C.; Starzewski, J. H.
Calculating the induced electromagnetic fields in real human head by deep transcranial magnetic stimulation.
Stimulation of deeper brain structures by transcranial magnetic stimulation (TMS) may be beneficial in the treatment of several neurological and psychiatric disorders. This paper presents numerical simulation of deep transcranial magnetic stimulation (dTMS) by considering double cone, H-and Halo coils. Three-dimensional distributions of the induced fields i.e. magnetic flux density, current density and electric fields in realistic head model by dTMS coils were calculated by impedance method and the results were compared with that of figure-of-eight coil. It was found that double cone and H-coils have significantly deep field penetration at the expense of induced higher and wider spread electrical fields in superficial cortical regions. The Halo coil working with a circular coil carrying currents in opposite directions provides a flexible way to stimulate deep brain structures with much lower stimulation in superficial brain tissues. PMID:24109807
Lu, Mai; Ueno, Shoogo
Deep transcranial magnetic stimulation as a treatment for psychiatric disorders: a comprehensive review.
Deep transcranial magnetic stimulation (TMS) is a technique of neuromodulation and neurostimulation based on the principle of electromagnetic induction of an electric field in the brain. The coil (H-coil) used in deep TMS is able to modulate cortical excitability up to a maximum depth of 6 cm and is therefore able not only to modulate the activity of the cerebral cortex but also the activity of deeper neural circuits. Deep TMS is largely used for the treatment of drug-resistant major depressive disorder (MDD) and is being tested to treat a very wide range of neurological, psychiatric and medical conditions. The aim of this review is to illustrate the biophysical principles of deep TMS, to explain the pathophysiological basis for its utilization in each psychiatric disorder (major depression, autism, bipolar depression, auditory hallucinations, negative symptoms of schizophrenia), to summarize the results presented thus far in the international scientific literature regarding the use of deep TMS in psychiatry, its side effects and its effects on cognitive functions. PMID:22559998
Bersani, F S; Minichino, A; Enticott, P G; Mazzarini, L; Khan, N; Antonacci, G; Raccah, R N; Salviati, M; Delle Chiaie, R; Bersani, G; Fitzgerald, P B; Biondi, M
Deep transcranial magnetic stimulation for the treatment of auditory hallucinations: a preliminary open-label study
PubMed Central
Background Schizophrenia is a chronic and disabling disease that presents with delusions and hallucinations. Auditory hallucinations are usually expressed as voices speaking to or about the patient. Previous studies have examined the effect of repetitive transcranial magnetic stimulation (TMS) over the temporoparietal cortex on auditory hallucinations in schizophrenic patients. Our aim was to explore the potential effect of deep TMS, using the H coil over the same brain region on auditory hallucinations. Patients and methods Eight schizophrenic patients with refractory auditory hallucinations were recruited, mainly from Beer Ya'akov Mental Health Institution (Tel Aviv university, Israel) ambulatory clinics, as well as from other hospitals outpatient populations. Low-frequency deep TMS was applied for 10 min (600 pulses per session) to the left temporoparietal cortex for either 10 or 20 sessions. Deep TMS was applied using Brainsway's H1 coil apparatus. Patients were evaluated using the Auditory Hallucinations Rating Scale (AHRS) as well as the Scale for the Assessment of Positive Symptoms scores (SAPS), Clinical Global Impressions (CGI) scale, and the Scale for Assessment of Negative Symptoms (SANS). Results This preliminary study demonstrated a significant improvement in AHRS score (an average reduction of 31.7% � 32.2%) and to a lesser extent improvement in SAPS results (an average reduction of 16.5% � 20.3%). Conclusions In this study, we have demonstrated the potential of deep TMS treatment over the temporoparietal cortex as an add-on treatment for chronic auditory hallucinations in schizophrenic patients. Larger samples in a double-blind sham-controlled design are now being preformed to evaluate the effectiveness of deep TMS treatment for auditory hallucinations. Trial registration This trial is registered with clinicaltrials.gov (identifier: NCT00564096).
Deep Transcranial Magnetic Stimulation for treatment-resistant bipolar depression: A case report of acute and maintenance efficacy
Microsoft Academic Search
Deep Transcranial Magnetic Stimulation (dTMS) is currently being evaluated as a possible treatment for several neuropsychiatric disorders and has been demonstrated as a safe and effective procedure. This case presents a patient with bipolar depression that has been treated with 20 daily consecutive dTMS sessions and with one dTMS session every 2 weeks for the following 3 months. Depressive symptoms
Francesco Saverio Bersani; Nicoletta Girardi; Livia Sanna; Lorenzo Mazzarini; Chiara Santucci; Giorgio D. Kotzalidis; Gabriele Sani; Pietro De Rossi; Ruggero N. Raccah; Saverio Simone Caltagirone; Mariella Battipaglia; Silvia Capezzuto; Giuseppe Bersani; Paolo Girardi
Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation
NASA Technical Reports Server (NTRS)
Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.
Andrews, Russell J.
Deep transcranial magnetic stimulation add-on for the treatment of auditory hallucinations: a double-blind study
Background About 25% of schizophrenia patients with auditory hallucinations are refractory to pharmacotherapy and electroconvulsive therapy. We conducted a deep transcranial magnetic stimulation (TMS) pilot study in order to evaluate the potential clinical benefit of repeated left temporoparietal cortex stimulation in these patients. The results were encouraging, but a sham-controlled study was needed to rule out a placebo effect. Methods A total of 18 schizophrenic patients with refractory auditory hallucinations were recruited, from Beer Yaakov MHC and other hospitals outpatient populations. Patients received 10 daily treatment sessions with low-frequency (1 Hz for 10 min) deep TMS applied over the left temporoparietal cortex, using the H1 coil at the intensity of 110% of the motor threshold. Procedure was either real or sham according to patient randomization. Patients were evaluated via the Auditory Hallucinations Rating Scale, Scale for the Assessment of Positive Symptoms-Negative Symptoms, Clinical Global Impressions, and Quality of Life Questionnaire. Results In all, 10 patients completed the treatment (10 TMS sessions). Auditory hallucination scores of both groups improved; however, there was no statistical difference in any of the scales between the active and the sham treated groups. Conclusions Low-frequency deep TMS to the left temporoparietal cortex using the protocol mentioned above has no statistically significant effect on auditory hallucinations or the other clinical scales measured in schizophrenic patients. Trial Registration Clinicaltrials.gov identifier: NCT00564096.
Canadian guidelines for the evidence-based treatment of tic disorders: behavioural therapy, deep brain stimulation, and transcranial magnetic stimulation.
This clinical guideline provides recommendations for nonpharmacological treatments for tic disorders. We conducted a systematic literature search for clinical trials on the treatment of tics. One evidence-based review (including 30 studies) and 3 studies on behavioural interventions, 3 studies on deep brain stimulation (DBS), and 3 studies on transcranial magnetic stimulation (TMS) met our inclusion criteria. Based on this evidence, we have made strong recommendations for the use of habit reversal therapy and exposure and response prevention, preferably embedded within a supportive, psychoeducational program, and with the option to combine either of these approaches with pharmacotherapy. Although evidence exists for the efficacy of DBS, the quality of this evidence is poor and the risks and burdens of the procedure are finely balanced with the perceived benefits. Our recommendation is that this intervention continues to be considered an experimental treatment for severe, medically refractory tics that have imposed severe limitations on quality of life. We recommend that the procedure should only be performed within the context of research studies and by physicians expert in DBS programming and in the management of tics. There is no evidence to support the use of TMS in the treatment of tics. However, the procedure is associated with a low rate of known complications and could continue to be evaluated within research protocols. The recommendations we provide are based on current knowledge, and further studies may result in their revision in future. PMID:22398000
Steeves, Thomas; McKinlay, B Duncan; Gorman, Daniel; Billinghurst, Lori; Day, Lundy; Carroll, Alan; Dion, Yves; Doja, Asif; Luscombe, Sandra; Sandor, Paul; Pringsheim, Tamara
Applications of transcranial magnetic stimulation
Over the past decade research and clinical applications of transcranial magnetic stimulation (TMS) have expanded greatly. These advances have depended on improvements in technology, in the models used to understand TMS biophysics, and in our understanding of TMS neurophysiology. Single-pulse TMS has been used extensively in studying motor and visual systems. Rapid, repetitive TMS (rTMS) has more powerful effects on
Charles M. Epstein
Transcranial magnetic stimulation and epilepsy
Epileptic conditions are characterized by an altered balance between excitatory and inhibitory influences at the cortical level. Transcranial magnetic stimulation (TMS) provides a noninvasive evaluation of separate excitatory and inhibitory functions of the cerebral cortex. In addition, repetitive TMS (rTMS) can modulate the excitability of cortical networks. We review the different ways that TMS has been used to investigate pathophysiological
Carlo Alberto Tassinari; Massimo Cincotta; Gaetano Zaccara; Roberto Michelucci
Transcranial magnetic stimulation: the method and application
Summary. Transcranial magnetic stimulation is a noninvasive method for stimulation of brain that is based on the ability of magnetic field to penetrate skull and brain meninges, subsequently inducing electric current in the brain tissues that produces neuronal depolarization and generation of action potentials. Moreover, transcranial magnetic stimulation has effects on neurochemical and synaptic processes in neurons. Due to its
Jacqueline H�ppner; Osvaldas Ruk�?nas
Transcranial magnetic stimulation and cognitive neuroscience
Transcranial magnetic stimulation has been used to investigate almost all areas of cognitive neuroscience. This article discusses the most important (and least understood) considerations regarding the use of transcranial magnetic stimulation for cognitive neuroscience and outlines advances in the use of this technique for the replication and extension of findings from neuropsychology. We also take a more speculative look forward
Vincent Walsh; Alan Cowey
Transcranial Magnetic Stimulation in Children
Developmental disabilities (e.g. attention deficit disorder; cerebral palsy) are frequently associated with deviations of the typical pattern of motor skill maturation. Neurophysiologic tools, such as transcranial magnetic stimulation (TMS), which probe motor cortex function, can potentially provide insights into both typical neuromotor maturation and the mechanisms underlying the motor skill deficits in children with developmental disabilities. These insights may set the stage for finding effective interventions for these disorders. We review the literature pertaining to the use of TMS in pediatrics. Most TMS-evoked parameters show age-related changes in typically developing children and some of these are abnormal in a number of childhood-onset neurological disorders. Although no TMS-evoked parameters are diagnostic for any disorder, changes in certain parameters appear to reflect disease burden or may provide a measure of treatment-related improvement. Furthermore, TMS may be especially useful when combined with other neurophysiologic modalities (e.g. fMRI). However, much work remains to be done to determine if TMS-evoked parameters can be used as valid and reliable biomarkers for disease-burden, the natural history of neurological injury and repair, and the efficacy of pharmacological and rehabilitation interventions.
Garvey, Marjorie A.; Mall, Volker
Transcranial magnetic stimulation during pregnancy.
The aim of the present study was to assess the safety and effectiveness of high-frequency repetitive transcranial magnetic stimulation (rTMS) in pregnant patients with depression. Thirty depressed pregnant patients received rTMS over the left prefrontal cortex for 6�days in a week, from Monday to Saturday for 3�weeks. The rTMS intensity was set at 100�% of the motor threshold. A 25-Hz stimulation with a duration of 2�s was delivered 20 times with 30-s intervals. A session comprised 1,000 magnetic pulses. Depression was rated using the 17-item Hamilton depression rating scale (HAMD) before and after treatment. Response was defined as a 50�% reduction of the HAMD score. Patients with HAMD scores less than 8 were considered to be in remission. The mean HAMD score for the study group decreased from 26.77?�?5.58 to 13.03?�?6.93 (p?0.001) after 18 sessions of rTMS. After the treatment period, 41.4�% of the study group demonstrated significant mood improvements as indexed by a reduction of more than 50�% on the HAMD score. In addition, 20.7�% attained remission (HAMD score?8), 34.5�% achieved a partial response, and 3.4�% had worsening in HAMD scores at the end of treatment. Treatment was well tolerated, and no significant adverse effects were reported. rTMS was well tolerated and found to be statistically and clinically effective in pregnant patients with treatment-resistant depression. This study contributed to the existing evidence of the antidepressant effect of rTMS in the treatment of depression in pregnancy. PMID:24248413
H?zl? Sayar, G�kben; Ozten, Eylem; Tufan, Evren; Cerit, Cem; Ka?an, Gaye; Dilbaz, Nesrin; Tarhan, Nevzat
Transcranial magnetic stimulation and the human brain
Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also
Mark Hallett
Transcranial Magnetic Stimulation Intensities in Cognitive Paradigms
BackgroundTranscranial magnetic stimulation (TMS) has become an important experimental tool for exploring the brain's functional anatomy. As TMS interferes with neural activity, the hypothetical function of the stimulated area can thus be tested. One unresolved methodological issue in TMS experiments is the question of how to adequately calibrate stimulation intensities. The motor threshold (MT) is often taken as a reference
Jakob A. Kaminski; Franziska M. Korb; Arno Villringer; Derek V. M. Ott; Joseph Najbauer
Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.
Hallett, Mark
Transcranial magnetic stimulation and aphasia rehabilitation.
Repetitive transcranial magnetic stimulation (rTMS) has been reported to improve naming in chronic stroke patients with nonfluent aphasia since 2005. In part 1, we review the rationale for applying slow, 1-Hz, rTMS to the undamaged right hemisphere in chronic nonfluent aphasia patients after a left hemisphere stroke; and we present a transcranial magnetic stimulation (TMS) protocol used with these patients that is associated with long-term, improved naming post-TMS. In part 2, we present results from a case study with chronic nonfluent aphasia where TMS treatments were followed immediately by speech therapy (constraint-induced language therapy). In part 3, some possible mechanisms associated with improvement after a series of TMS treatments in stroke patients with aphasia are discussed. PMID:22202188
Naeser, Margaret A; Martin, Paula I; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Bashir, Shahid; Pascual-Leone, Alvaro
Classical conditioned learning using transcranial magnetic stimulation
This study examined whether brain responses to transcranial magnetic stimulation (TMS) would be amenable to classical conditioning.\\u000a Motor cortex in human participants was stimulated with TMS pulses, which elicited a peripheral motor response in the form\\u000a of a motor evoked potential (MEP). The TMS pulses were paired with audio-visual cues that served as conditioned stimuli. Over\\u000a the course of training,
B. Luber; P. Balsam; T. Nguyen; M. Gross; S. H. Lisanby
Use and safety of a new repetitive transcranial magnetic stimulator
In order to test a new repetitive transcranial magnetic stimulator, the Dantec MagPro, we administered transcranial magnetic stimulation (TMS) at 1 Hz and 125% of motor threshold for an average of 204 s (until the coil temperature reached 40�C) and 20 Hz stimulation at 100% of motor threshold for 2 s every minute for 10 min, on different days to
Eric M. Wassermann; Jordan Grafman; Cherisse Berry; Caroline Hollnagel; Krista Wild; Kim Clark; Mark Hallett
Improvement in Parkinsonian symptoms after repetitive transcranial magnetic stimulation
Transcranial magnetic stimulation has been used in the diagnosis of neurological lesions, but has also been shown to be useful in the treatment of depression. We have now examined the effect of applying transcranial magnetic stimulation daily for 10 days in a sample of 10 patients with Parkinson�s disease in whom maximal benefit was being obtained from drug therapy. The
Judit Mally; Trevor W. Stone
Repetitive transcranial magnetic stimulation improves depersonalization: a case report.
Depersonalization disorder is a poorly understood and treatment-resistant condition. This report describes a patient with depersonalization disorder who underwent six sessions of repetitive transcranial magnetic stimulation on the left dorsolateral prefrontal cortex. Repetitive transcranial magnetic stimulation produced a 28% reduction on depersonalization scores. PMID:15115950
Jim�nez-Genchi, Alejandro M
Dosimetry of typical transcranial magnetic stimulation devices
The therapeutic staff using transcranial magnetic stimulation (TMS) devices could be exposed to magnetic pulses. In this paper, dependence of induced currents in real human man model on different coil shapes, distance between the coil and man model as well as the rotation of the coil in space have been investigated by employing impedance method. It was found that the figure-of-eight coil has less leakage magnetic field and low current density induced in the body compared with the round coil. The TMS power supply cables play an important role in the induced current density in human body. The induced current density in TMS operator decreased as the coil rotates from parallel position to perpendicular position. Our present study shows that TMS operator should stand at least 110 cm apart from the coil.
Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images
Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.
Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; Gonz�lez, O. Jorge J.; M�rquez, F. Jorge A.
Transcranial Magnetic Stimulation and Aphasia Rehabilitation
Repetitive transcranial magnetic stimulation (rTMS) has been reported to improve naming in chronic stroke patients with nonfluent aphasia since 2005. In Part 1, we review the rationale for applying slow, 1 Hz, rTMS to the undamaged right hemisphere in chronic nonfluent aphasia patients following a left hemisphere stroke; and present a TMS protocol used with these patients that is associated with long-term, improved naming post- TMS. In Part, 2 we present results from a case study with chronic nonfluent aphasia where TMS treatments were followed immediately by speech therapy (constraint-induced language therapy). In Part 3, some possible mechanisms associated with improvement following a series of TMS treatments in stroke patients with aphasia are discussed.
Naeser, Margaret A.; Martin, Paula I; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Bhashir, Shahid; Pascual-Leone, Alvaro
Transcranial magnetic stimulation screening for cord compression in cervical spondylosis
ObjectiveCervical spondylosis (CS) often results in various degrees of cord compression, which can be evaluated functionally with transcranial magnetic stimulation (TMS). We investigate the use of TMS as a screening tool for myelopathy in CS.
Y. L. Lo; L. L. Chan; W. Lim; S. B. Tan; C. T. Tan; J. L. T. Chen; S. Fook-Chong; P. Ratnagopal
Transcranial Magnetic Stimulation After Spinal Cord Injury.
OBJECTIVE: To review the basic principles and techniques of transcranial magnetic stimulation (TMS) and provide information and evidence regarding its applications in spinal cord injury clinical rehabilitation. METHODS: A review of the available current and historical literature regarding TMS was conducted, and a discussion of its potential use in spinal cord injury rehabilitation is presented. RESULTS: TMS provides reliable information about the functional integrity and conduction properties of the corticospinal tracts and motor control in the diagnostic and prognostic assessment of various neurological disorders. It allows one to follow the evolution of motor control and to evaluate the effects of different therapeutic procedures. Motor-evoked potentials can be useful in follow-up evaluation of motor function during treatment and rehabilitation, specifically in patients with spinal cord injury and stroke. Although studies regarding somatomotor functional recovery after spinal cord injury have shown promise, more trials are required to provide strong and substantial evidence. CONCLUSIONS: TMS is a promising noninvasive tool for the treatment of spasticity, neuropathic pain, and somatomotor deficit after spinal cord injury. Further investigation is needed to demonstrate whether different protocols and applications of stimulation, as well as alternative cortical sites of stimulation, may induce more pronounced and beneficial clinical effects. PMID:23321378
Awad, Basem I; Carmody, Margaret A; Zhang, Xiaoming; Lin, Vernon W; Steinmetz, Michael P
Imaging the brain before, during, and after transcranial magnetic stimulation
This article provides a brief overview of current trends in combining neuroimaging and transcranial magnetic stimulation (TMS). First, I outline the utility of magnetic-resonance imaging (MRI) and frameless stereotaxy for planning, monitoring and documenting the location of the TMS coil relative to the subjects brain. Second, I describe two novel methods, based on the combination of TMS with positron emission
Tomas Paus
Transcranial magnetic stimulation can influence the selection of motor programmes
Transcranial magnetic stimulation is becoming increasingly popular to study the rapidly conducting output from the motor cortex. Little is known about the effects of such stimuli on other aspects of cortical function. In the study single magnetic stimuli, subthreshold for movement, produced significant preference for selection of one hand in a forced-choice task. The hand preference depended upon the direction
K. Ammon; S. C. Gandevia
Temporal aspects of visual search studied by transcranial magnetic stimulation
Transcranial magnetic stimulation was applied over the parietal visual cortex of subjects while they were performing �popout� or conjunction visual search tasks in arrays containing eight distractors. Magnetic stimulation had no detrimental effect on the performance of pop-out search, but did significantly increase reaction times on conjunction search when stimulation was applied over the right parietal cortex 100 msec after
Elisabeth Ashbridge; Vincent Walsh; Alan Cowey
Transcranial magnetic stimulation induces alterations in brain monoamines
Summary Transcranial magnetic stimulation has been suggested as a possible therapeutic tool in depression. In behavioral models of depression, magnetic stimulation induced similar effects to those of electroconvulsive shock. This study demonstrates the effect of a single session of rapid TMS on tissue monoamines in rat brain. Alterations in monoamines were selective and specific in relation to brain areas and
D. Ben-Shachar; R. H. Belmaker; N. Grisaru; E. Klein
Transcranial Magnetic Stimulation Study in Hereditary Spastic Paraparesis
The motor-evoked potentials and the cortical excitability by transcranial magnetic stimulation (TMS) were studied in a family with chromosome 2p linked (due to mutations in spastin) and in a family with chromosome 16q linked (due to mutations in paraplegin) hereditary spastic paraparesis (HSP), in order to evaluate the utility of these techniques in identifying the subgroups of the disease. Central
R. Nardone; F. Tezzon
Transcranial magnetic stimulation can measure and modulate learning and memory
The potential uses for Transcranial Magnetic Stimulation (TMS) in the study of learning and memory range from a method to map the topography and intensity of motor output maps during visuomotor learning to inducing reversible lesions that allow for the precise temporal and spatial dissection of the brain processes underlying learning and remembering. Single-pulse TMS appears to be adequate to
J Grafman; E Wassermann
Transcranial magnetic stimulation, synaptic plasticity and network oscillations
Transcranial magnetic stimulation (TMS) has quickly progressed from a technical curiosity to a bona-fide tool for neurological research. The impetus has been due to the promising results obtained when using TMS to uncover neural processes in normal human subjects, as well as in the treatment of intractable neurological conditions, such as stroke, chronic depression and epilepsy. The basic principle of
Patricio T Huerta; Bruce T Volpe
Transcranial magnetic stimulation studies of cognition: an emerging field
In this short review, we consider the applica- tion of transcranial magnetic stimulation (TMS) to the study of cognitive function. Following an introduction to the technique, we consider its possible mechanisms of action. We then review the studies that have applied TMS to the investigation of cognition. In the majority of these investigations, TMS has been applied to disrupt function
Marjan Jahanshahi; John Rothwell
Motor and phosphene thresholds: a transcranial magnetic stimulation correlation study
Objective: To investigate the stability of visual phosphene thresholds and to assess whether they correlate with motor thresholds. Background: Currently, motor threshold is used as an index of cortical sensitivity so that in transcranial magnetic stimulation (TMS) experiments, intensity can be set at a given percentage of this value. It is not known whether this is a reasonable index of
L. M. Stewart; V. Walsh; J. C. Rothwell
Therapeutic application of repetitive transcranial magnetic stimulation: a review
Abstract Transcranial magnetic stimulation (TMS), a non-invasive means of electrically stimulating neurons in the human cerebral cortex, is able to modify neuronal activity locally and at distant sites when,delivered in series or trains of pulses. Data from stimulation of the motor cortex suggest that the type of effect on the excitability of the cortical network depends on the frequency of
Em Wassermann; Sh Lisanby
Effect of antipsychotics on cortical inhibition using transcranial magnetic stimulation
Previous studies suggest that antipsychotic medications may alter cortical inhibition (CI). The current study was designed to determine if typical or atypical antipsychotics indeed alter CI in healthy subjects using three CI paradigms as measured with transcranial magnetic stimulation (TMS): short interval intracortical inhibition (SICI), cortical silent period (CSP) and transcallosal inhibition (TCI). CI was measured before, 6 and 24�h
Zafiris J. Daskalakis; Bruce K. Christensen; Robert Chen; Paul B. Fitzgerald; Robert B. Zipursky; Shitij Kapur
Transcranial Magnetic Stimulation and Its Applications in Children
Transcranial magnetic stimulation (TMS) provides a non-invasive method of induction of focal currents in the brain as well as transient modulation of the function of the targeted cortex. TMS is now widely used as a diagnostic tool in adults. In children, its application to date has been limited, even though TMS offers unique opportunities to gain insights into the neurophysiology
Kuang-Lin Lin; Alvaro Pascual-Leone
Transcranial magnetic stimulation in patients with cerebellar stroke.
Conduction time of the central motor pathways (CMCT) by transcranial magnetic stimulation (TMS) was performed within the first two weeks in 7 patients with isolated hemicerebellar lesions after stroke. Cerebellar infarcts were small (< 2 cm in diameter) in 5 patients and no brainstem structure was involved in CT studies. The threshold (3 cases) and CMCT (4 cases) were abnormal or asymmetric by stimulation of the motor cortex contralateral to the impaired hemicerebellum. The follow-up study in 2 patients revealed electrophysiological improvement closely related to clinical cerebellar recovery rate. CMCT was significantly longer by cortex stimulation contralateral to the impaired hemicerebellum than by ipsilateral stimulation. Prolonged CMCT was significantly correlated with the rated severity of cerebellar signs. Increased threshold may be due to depressed facilitating action of the deep cerebellar nuclei on contralateral motor cortex. Abnormal CMCT might result in reduced size and increased dispersion of the efferent volleys. Recovery of electrophysiological results could represent in part true potentially reversible functional deficit. Whichever the pathophysiological mechanisms involved, our results demonstrate that the cerebellum dysfunction plays a role in the abnormalities of CMCT elicited by TMS. PMID:9286629
Cruz-Mart�nez, A; Arpa, J
Repetitive transcranial magnetic stimulation (rTMS) in depression
Transcranial magnetic stimulation (TMS) is a relatively non-invasive technique to interfere with the function of small cortical\\u000a areas through currents induced by alternating magnetic fields emanating from a handheld coil placed directly above the targeted\\u000a area. This technique has clear effects on a whole range of measures of brain function and has become an important research tool in neuropsychiatry. More
Thomas E. Schlaepfer; Markus Kosel; Hans-Ulrich Fisch
Enhancement of phonological memory following Transcranial Magnetic Stimulation
Abstract. Phonologically similar items (mell, rell, gell) are more difficult to remember than dissimilar items (shen, floy, stap), likely because of mutual interference of the items in the phonological store. Low-frequency transcranial magnetic,stimulation (TMS), guided by functional magnetic resonance imaging (fMRI) was used to disrupt this phonological confusion by stimulation of the left inferior parietal (LIP) lobule. Subjects received TMS
Matthew P. Kirschen; Mathew S. Davis-ratner; Thomas E. Jerde; Pam Schraedley-desmond; John E. Desmond
Registration and Visualization of Transcranial Magnetic Stimulation on MR Images
Transcranial Magnetic Stimulation (TMS) has been widely used in the mapping of the primary motor cortex, as well as in the study of language, memory, mood, auditory or visual perception [4]. Similarly to EEG or MEG, it provides informa-tion-Motor Evoked Potentials (MEP)-located on the surface of the scalp and requires a registration between the physical space (PhS) and a MRI
Olivier Cuisenaire; Matthieu Ferrant; Y. Vandermeeren; E. Olivier; Benoit M. Macq
Cortical Hypoexcitability in Chronic Smokers? A Transcranial Magnetic Stimulation Study
Studies in animal models and humans indicate that chronic nicotine intake influences neuronal excitability, resulting in functional and structural CNS changes. The aim of the present study was to explore human primary motor cortex (M1) excitability with transcranial magnetic stimulation (TMS) in chronic smokers. A total of 44 right-handed volunteers, aged 20-30 years, participated in the study. Chronic smokers were
Nicolas Lang; Alkomiet Hasan; Elke Sueske; Walter Paulus; Michael A Nitsche
Studies in animal models and humans indicate that chronic nicotine intake influences neuronal excitability, resulting in functional and structural CNS changes. The aim of the present study was to explore human primary motor cortex (M1) excitability with transcranial magnetic stimulation (TMS) in chronic smokers. A total of 44 right-handed volunteers, aged 20�30 years, participated in the study. Chronic smokers were
Transcranial magnetic stimulation for auditory hallucinations in schizophrenia
It has been suggested that low frequency transcranial magnetic stimulation (TMS) over left temporo-parietal cortex may reduce the frequency and intensity of auditory hallucinations in schizophrenia. Sixteen patients with hallucinations, treatment-resistant for at least 2 months, were randomised into a placebo-controlled crossover study of TMS at 1 Hz and 80% of motor threshold over left temporo-parietal cortex. Treatment periods lasted
Andrew M McIntosh; David Semple; Katherine Tasker; Lesley K Harrison; David G. C Owens; Eve C Johnstone; Klaus P Ebmeier
Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain
Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS
Ru-Rong Ji; Carlos D. Aizenman; Charles M. Epstein; Dike Qiu; Justin C. Huang; Fabio Rupp
Modulation of corticospinal excitability by repetitive transcranial magnetic stimulation
Abstract Objective: Repetitive transcranial magnetic stimulation (rTMS) is able to modulate the corticospinal excitability and the effects appear to last beyond the duration of the rTMS itself. Different studies, employing different rTMS parameters, report different modulation of corticospinal excitability ranging from inhibition to facilitation. Intraindividual variability of these effects and their reproducibility are unclear. Methods: We examined the modulatory effects
Fumiko Maeda; Julian Paul Keenan; Jose Maria Tormos; Helge Topka; Alvaro Pascual-leone
Transcranial magnetic stimulation: new insights into representational cortical plasticity
.�� In the last decade, transcranial magnetic stimulation (TMS) has been used increasingly as a tool to explore the mechanisms\\u000a and consequences of cortical plasticity in the intact human cortex. Because the spatial accuracy of the technique is limited,\\u000a we refer to this as plasticity at a regional level. Currently, TMS is used to explore regional reorganization in three different
Hartwig Roman Siebner; John Rothwell
Objective: Repetitive transcranial magnetic stimulation (rTMS) is able to modulate the corticospinal excitability and the effects appear to last beyond the duration of the rTMS itself. Different studies, employing different rTMS parameters, report different modulation of corticospinal excitability ranging from inhibition to facilitation. Intraindividual variability of these effects and their reproducibility are unclear.Methods: We examined the modulatory effects of rTMS
Fumiko Maeda; Julian Paul Keenan; Jose Maria Tormos; Helge Topka; Alvaro Pascual-Leone
Localising awareness of action with transcranial magnetic stimulation
Seven subjects reacted to an auditory stimulus by pressing a response key and judged their reaction time (RT) by reporting\\u000a the position of a rotating clock-hand at which they pressed the key. Transcranial magnetic stimulation (TMS) was delivered\\u000a either over primary motor cortex (MI) or more anteriorly (with the centre of the coil over FCz) 75 ms before each subject�s
Patrick Haggard; Elena Magno
Recent advances in transcranial magnetic stimulation: From first principles to medical applications
Transcranial magnetic stimulation (TMS) is a technique to stimulate the human brain transcranially by a coil positioned on the surface of the head. Time-varying magnetic fields generated by the coil induce electric fields which stimulate neurons in the brain. By using a figure-eight coil, localized area of the brain can be stimulated, which enables us to study dynamic neuronal connectivity
Shoogo Ueno
Comparison of descending volleys evoked by transcranial magnetic and electric stimulation in conscious humans
Objectives: The present experiments were designed to compare the understanding of the transcranial electric and magnetic stimulation of the human motorcortex.Methods: The spinal volleys evoked by single transcranial magnetic or electric stimulation over the cerebral motor cortex were recorded from a bipolar electrode inserted into the cervical epidural space of two conscious human subjects. These volleys were termed D- and
V Di Lazzaro; A Oliviero; P Profice; E Saturno; F Pilato; A Insola; P Mazzone; P Tonali; J. C Rothwell
Prevention of supine hypotensive syndrome in pregnant women treated with transcranial magnetic stimulation.
In our studies of transcranial magnetic stimulation in pregnant women with major depressive disorder, two subjects had an episode of supine hypotensive syndrome and one subject had an episode of dizziness without hypotension. Prevention of the supine hypotensive syndrome in pregnant women receiving transcranial magnetic stimulation is described. PMID:24768354
Kim, Deborah Rubin; Wang, Eileen
Transcranial Magnetic Stimulation: Modelling and New Techniques.
National Technical Information Service (NTIS)
The aim of this thesis was to develop physical understanding of magnetic stimulation and to build models that could provide new insights for utilizing the technique. For this purpose, two principal issues had to be addressed: (1) macroscopic electromagnet...
J. Ruohonen
Transcranial electric and magnetic stimulation: technique and paradigms.
Transcranial electrical and magnetic stimulation techniques encompass a broad physical variety of stimuli, ranging from static magnetic fields or direct current stimulation to pulsed magnetic or alternating current stimulation with an almost infinite number of possible stimulus parameters. These techniques are continuously refined by new device developments, including coil or electrode design and flexible control of the stimulus waveforms. They allow us to influence brain function acutely and/or by inducing transient plastic after-effects in a range from minutes to days. Manipulation of stimulus parameters such as pulse shape, intensity, duration, and frequency, and location, size, and orientation of the electrodes or coils enables control of the immediate effects and after-effects. Physiological aspects such as stimulation at rest or during attention or activation may alter effects dramatically, as does neuropharmacological drug co-application. Non-linear relationships between stimulus parameters and physiological effects have to be taken into account. PMID:24112906
Paulus, Walter; Peterchev, Angel V; Ridding, Michael
Transcranial magnetic stimulation and magnetic resonance imaging of currents and conductivity tomography of the brain
This paper focuses on two topics in biomagnetics: transcranial magnetic stimulation (TMS) and conductivity magnetic resonance imaging (MRI). We studied an associative memory task involving pairs of Kanji (Chinese) pictographs and unfamiliar abstract patterns. During memory encoding, TMS was applied over the left and right dorsolateral prefrontal cortex (DLPFC). A significant (P<0.05) reduction in subsequent recall of new associations was
Shoogo Ueno; Masaki Sekino
Transcranial Magnetic Stimulation Measures in Attention-Deficit/Hyperactivity Disorder
Children affected by Attention-Deficit/Hyperactivity Disorder have diminished intra-hemispheric inhibition (Short Interval Cortical Inhibition) as measured by Transcranial Magnetic Stimulation. This study�s objective is to determine whether inter-hemispheric inhibition (Ipsilateral Silent Period Latency) correlates with clinical behavioral rating and motor control deficits of affected children. In 114 8�12 year old, right-handed children (age/sex-matched, 50 affected, 64 controls), we performed comprehensive assessments of behavior, motor skills and cognition. Using Transcranial Magnetic Stimulation, we reliably elicited Ipsilateral Silent Period in 54 children (23 affected) - all were on average older than those who had unobtainable measures. Mean Ipsilateral Silent Period latency was 5 milliseconds longer in the affected group (p=0.007). Longer latencies correlated with more severe behavioral symptom scores (r=0.38, p=0.007), particularly hyperactivity (r=0.39, p=0.006), as well as with worse motor ratings on the Physical and Neurological Examination for Soft Signs (r=0.27, p=0.05). Longer latency also correlated with Short Interval Cortical Inhibition (r=0.36, p=0.008). In conclusion, longer Ipsilateral Silent Period latencies suggest interhemispheric inhibitory signaling is slower in affected children. The deficit in this inhibitory measure may underlie developmental, behavioral and motor impairments in children with Attention-Deficit/Hyperactivity Disorder.
Transcranial Magnetic Stimulation in Child Neurology: Current and Future Directions
Transcranial magnetic stimulation (TMS) is a method for focal brain stimulation based on the principle of electromagnetic induction, where small intracranial electric currents are generated by a powerful, rapidly changing extracranial magnetic field. Over the past 2 decades TMS has shown promise in the diagnosis, monitoring, and treatment of neurological and psychiatric disease in adults, but has been used on a more limited basis in children. We reviewed the literature to identify potential diagnostic and therapeutic applications of TMS in child neurology and also its safety in pediatrics. Although TMS has not been associated with any serious side effects in children and appears to be well tolerated, general safety guidelines should be established. The potential for applications of TMS in child neurology and psychiatry is significant. Given its excellent safety profile and possible therapeutic effect, this technique should develop as an important tool in pediatric neurology over the next decade.
Frye, Richard E.; Rotenberg, Alexander; Ousley, Molliann; Pascual-Leone, Alvaro
Localization of Magnetic Field Structure of Multi-Current Loops on Axisymmetrical Model for Transcranial Magnetic Stimulation
We calculate magnetic field distributions from multi-current loops for transcranial magnetic stimulation (TMS). In TMS, it is important to produce locally strong magnetic fields and apply eddy-currents only to the aimed cell in a deep region of the brain. First, we investigate the field structure around a single current loop. We find that a single loop generates the convexed field on a certain plane parallel to the loop surface. Second, we study an axisymmetrical model of three-current loops, i.e., a main-coil and two sub-coils, in which the fields are significantly localized in the vertical direction at a symmetrical plane on the central axis compared with that of a single loop.
Okita, Taishi; Takagi, Toshiyuki
Transcranial magnetic stimulation in amyotrophic and primary lateral sclerosis.
Conduction of the central motor pathways after transcranial magnetic stimulation (TMS) was investigated in 7 patients with amyotrophic lateral sclerosis (ALS) and 1 case with primary lateral sclerosis (PLS). Threshold intensity, central motor conduction time (CMCT) and amplitude of the motor evoked potentials (MEPs) were evaluated. Threshold was abnormal in 85% of tested limbs, and CMCT prolonged and amplitude of the MEPs attenuated in 28.5% of patients with ALS. Abnormal CMCT was asymmetric and related to clinical score. MEPs were absent in lower limbs in PLS, with prolonged or attenuated amplitude of the MEPs in upper limbs. EMG showed widespread signs of lower motor neuron involvement in ALS, but not in PLS. Cranial MRI showed frontoparietal cortical atrophy, more marked in pre-central gyrus, and SPECT there was lower tracer uptake in the perirolandic area in the PLS patient. EMG examination, TMS, cranial MRI and SPECT can help in the diagnosis of PLS. PMID:10421999
Cruz Mart�nez, A; Trejo, J M
Use and safety of a new repetitive transcranial magnetic stimulator.
In order to test a new repetitive transcranial magnetic stimulator, the Dantec MagPro, we administered transcranial magnetic stimulation (TMS) at 1 Hz and 125% of motor threshold for an average of 204 s (until the coil temperature reached 40 degrees C) and 20 Hz stimulation at 100% of motor threshold for 2 s every minute for 10 min, on different days to 10 healthy volunteers. We stimulated 6 scalp positions (primary motor area (M1) and sites 5 cm anterior and posterior on each hemisphere) with an 8-shaped coil. We tested immediate and delayed memory, verbal fluency, prolactin levels and EEG at the beginning of the study and after stimulation on each day. No abnormalities were found. Motor evoked potentials evoked with 1 Hz stimulation diminished progressively in amplitude, and 1 Hz stimulation of M1 caused inhibition lasting at least 1 min in 3 of 4 subjects who were tested with 0.1 Hz stimulation before and after the 1 Hz stimulation period. This did not occur with 20 Hz stimulation. Finger tapping frequency was tested at the beginning of the study and after TMS at each scalp site. Finger tapping rate data from 6 additional subjects who were stimulated in an identical fashion with a different stimulator were also analyzed. There was an increase in tapping rate after TMS which was independent of scalp site. This was most pronounced with 1 Hz stimulation at 125% of threshold and reached statistical significance in the hand contralateral to the stimulation. The results of this study indicate that rTMS with the MagPro stimulator is safe at specific combinations of intensity, frequency and train duration. PMID:8913194
Wassermann, E M; Grafman, J; Berry, C; Hollnagel, C; Wild, K; Clark, K; Hallett, M
Enhancing Warfighter Cognitive Abilities with Transcranial Magnetic Stimulation: A Feasibility Analysis.
This study examined the feasibility of using transcranial magnetic stimulation (TMS) to enhance warfighter cognitive abilities. An extensive literature review was conducted and several TMS laboratories were visited. Discussions were also held with several...
J. T. Nelson
Slow Transcranial Magnetic Stimulation, Long-Term Depotentiation, and Brain Hyperexcitability Disorders
Objective: Many clinical syndromes in neuropsychiatry suggest focal brain acti- vation. Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a method for selectively altering neural activity. Method: Studies assessing effects of \\
Ralph E. Hoffman; Idil Cavus
Effect of Prefrontal Repetitive Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder: A Preliminary Study
Objective: Prefrontal mechanisms are implicated in obsessive-compulsive disorder. The authors investigated whether prefrontal repetitive transcranial magnetic stimulation influenced obsessive-compulsive disorder symptoms. Method: Twelve patients with obsessive-compulsive disorder were given repetitive transcranial magnetic stimulation (80% motor threshold, 20 Hz\\/2 seconds per minute for 20 minutes) to a right lateral prefrontal, a left lateral prefrontal, and a midoccipital (control) site on separate
Benjamin D. Greenberg; Mark S. George; Juliet D. Martin; Jonathan Benjamin; Thomas E. Schlaepfer; Margaret Altemus; Eric M. Wassermann; Robert M. Post; Dennis L. Murphy
Medical devices; neurological devices; classification of the transcranial magnetic stimulator for headache. Final order.
The Food and Drug Administration (FDA) is classifying the transcranial magnetic stimulator for headache into class II (special controls). The special controls that will apply to the device are identified in this order, and will be part of the codified language for the transcranial magnetic stimulator for headache classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:25016622
Deep Brain Stimulation using Magnetic Fields
New applications for transcranial magnetic stimulation are developing rapidly for both diagnostic and therapeutic purposes. Therefore so is the demand for improved performance, particularly in terms of their ability to stimulate deeper regions of the brain and to do so selectively. The coil designs that are used presently are limited in their ability to stimulate the brain at depth and with high spatial focality. Consequently, any improvement in coil performance would have a significant impact in extending the usefulness of TMS in both clinical applications and academic research studies. New and improved coil designs have then been developed, modeled and tested as a result of this work. A large magnetizing coil, 300mm in diameter and compatible with a commercial TMS system has been constructed to determine its feasibility for use as a deep brain stimulator. The results of this work have suggested directions that could be pursued in order to further improve the coil designs.
Jiles, David; Williams, Paul; Crowther, Lawrence
Transcranial magnetic stimulation (TMS) has quickly progressed from a technical curiosity to a bona-fide tool for neurological research. The impetus has been due to the promising results obtained when using TMS to uncover neural processes in normal human subjects, as well as in the treatment of intractable neurological conditions, such as stroke, chronic depression and epilepsy. The basic principle of TMS is that most neuronal axons that fall within the volume of magnetic stimulation become electrically excited, trigger action potentials and release neurotransmitter into the postsynaptic neurons. What happens afterwards remains elusive, especially in the case of repeated stimulation. Here we discuss the likelihood that certain TMS protocols produce long-term changes in cortical synapses akin to long-term potentiation and long-term depression of synaptic transmission. Beyond the synaptic effects, TMS might have consequences on other neuronal processes, such as genetic and protein regulation, and circuit-level patterns, such as network oscillations. Furthermore, TMS might have non-neuronal effects, such as changes in blood flow, which are still poorly understood.
Huerta, Patricio T; Volpe, Bruce T
Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.
Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio
Focal depression of cortical excitability induced by fatiguing muscle contraction: a transcranial magnetic stimulation study
Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the motor cortex were recorded in separate sessions to assess changes in motor cortex excitability after a fatiguing isometric maximal voluntary contraction (MVC) of the right ankle dorsal flexor muscles. Five healthy male subjects, aged 37.4�4.2 years (mean�SE), were seated in a chair equipped
W. Barry McKay; Stephen M. Tuel; Arthur M. Sherwood; Dobrivoje S. Stoki?; Milan R. Dimitrijevi?
SUMMARY Transcranial magnetic stimulation (TMS) is a new, non-invasive method inducing physiologic changes in relatively small areas of human cerebral cortex. TMS is used to induce artificial cortical lesions and thus affects different cognitive functions which can be further explored. TMS, as applied in cognitive research, is used as single pulse, pair pulse, or rapid-rate pulse (repetitive) TMS. Studies on
The effect of transcranial magnetic stimulation on long-term potentiation in rat hippocampus
We investigated the effect of transcranial magnetic stimulation (TMS) on the brain by focusing on long-term potentiation (LTP) in the rat hippocampus. Male Wistar rats were magnetically stimulated by a round coil positioned over the rat's head. The stimulator delivered biphasic cosine current pulses 238 ?s in duration. The peak magnetic fields were set to 0.50 T (motor threshold) at
Mari Ogiue-Ikeda; Suguru Kawato; Shoogo Ueno
Repetitive Transcranial Magnetic Stimulation Improves Handwriting in Parkinson's Disease
Background. Parkinson disease (PD) is characterized by hypometric movements resulting from loss of dopaminergic neurons in the substantia nigra. PD leads to decreased activation of the supplementary motor area (SMA); the net result of these changes is a poverty of movement. The present study determined the impact of 5?Hz repetitive transcranial magnetic stimulation (rTMS) over the SMA on a fine motor movement, handwriting (writing cursive �l�s), and on cortical excitability, in individuals with PD. Methods. In a cross-over design, ten individuals with PD were randomized to receive either 5?Hz or control stimulation over the SMA. Immediately following brain stimulation right handed writing was assessed. Results. 5?Hz stimulation increased vertical size of handwriting and diminished axial pressure. In addition, 5?Hz rTMS significantly decreased the threshold for excitability in the primary motor cortex. Conclusions. These data suggest that in the short term 5?Hz rTMS benefits functional fine motor task performance, perhaps by altering cortical excitability across a network of brain regions. Further, these data may provide the foundation for a larger investigation of the effects of noninvasive brain stimulation over the SMA in individuals with PD.
Randhawa, Bubblepreet K.; Farley, Becky G.; Boyd, Lara A.
Numerical modelling of plasticity induced by transcranial magnetic stimulation.
We use neural field theory and spike-timing dependent plasticity to make a simple but biophysically reasonable model of long-term plasticity changes in the cortex due to transcranial magnetic stimulation (TMS). We show how common TMS protocols can be captured and studied within existing neural field theory. Specifically, we look at repetitive TMS protocols such as theta burst stimulation and paired-pulse protocols. Continuous repetitive protocols result mostly in depression, but intermittent repetitive protocols in potentiation. A paired pulse protocol results in depression at short ( < ? 10 ms) and long ( > ? 100 ms) interstimulus intervals, but potentiation for mid-range intervals. The model is sensitive to the choice of neural populations that are driven by the TMS pulses, and to the parameters that describe plasticity, which may aid interpretation of the high variability in existing experimental results. Driving excitatory populations results in greater plasticity changes than driving inhibitory populations. Modelling also shows the merit in optimizing a TMS protocol based on an individual's electroencephalogram. Moreover, the model can be used to make predictions about protocols that may lead to improvements in repetitive TMS outcomes. PMID:24150916
Wilson, M T; Goodwin, D P; Brownjohn, P W; Shemmell, J; Reynolds, J N J
Stimulating the lip motor cortex with transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception. Researchers have used single-pulse and repetitive TMS to stimulate the lip representation in the motor cortex. The excitability of the lip motor representation can be investigated by applying single TMS pulses over this cortical area and recording TMS-induced motor evoked potentials (MEPs) via electrodes attached to the lip muscles (electromyography; EMG). Larger MEPs reflect increased cortical excitability. Studies have shown that excitability increases during listening to speech as well as during�viewing speech-related movements. TMS can be used also to disrupt the lip motor representation. A 15-min train of low-frequency sub-threshold repetitive stimulation has been shown to suppress motor excitability for a further 15-20 min. This TMS-induced disruption of the motor lip representation impairs subsequent performance in demanding speech perception tasks and modulates auditory-cortex responses to speech sounds. These findings are consistent with the suggestion that the motor cortex contributes to speech perception. This article describes how to localize the lip representation in the motor cortex and how to define the appropriate stimulation intensity for carrying out both single-pulse and repetitive TMS experiments. PMID:24962266
M�tt�nen, Riikka; Rogers, Jack; Watkins, Kate E
Measurement of evoked electroencephalography induced by transcranial magnetic stimulation
This study focused on the measurement of evoked potentials induced by transcranial magnetic stimulation (TMS) for observing the neuronal connectivity in the brain. We developed an electroencephalography (EEG) measurement system to eliminate the electromagnetic interaction emitted from TMS. EEG activities 5 ms after TMS stimulation were measured. Using this artifact free amplifier, we investigated the intensity dependence of brain activation induced by TMS. When the stimulus intensity was changed at three levels, TMS-evoked EEG responses were measured. Several components of the evoked potential appeared at 9 ms, 20 ms, and 50 ms after stimulation. A large response appeared at about 9 ms after cerebellar TMS. There was a significant dependence of these responses on the stimulus intensity. During right-hand side motor area stimulation, there was no clear peak of the wave forms within 10 ms latency. Occipital stimulation caused more evoked responses to spread to the center of the brain than at other areas of stimulation. The evoked signal by TMS was possibly conducted posteriorly to anteriorly along the pathways of the neuronal fiber exiting the cerebellum into the cerebral cortex.
Iramina, Keiji; Maeno, Takashi; Nonaka, Yukio; Ueno, Shoogo
Research with transcranial magnetic stimulation in the treatment of aphasia.
Repetitive transcranial magnetic stimulation (rTMS) has been used to improve language behavior, including naming, in stroke patients with chronic, nonfluent aphasia. Part 1 of this article reviews functional imaging studies related to language recovery in aphasia. Part 2 reviews the rationale for using rTMS to treat nonfluent aphasia (based on functional imaging) and presents our current rTMS protocol. We present language results from our rTMS studies as well as imaging results from overt naming functional MRI scans obtained before and after a series of rTMS treatments. Part 3 presents results from a pilot study in which rTMS treatments were followed immediately by constraint-induced language therapy. Part 4 reviews our diffusion tensor imaging study examining the possible connectivity of the arcuate fasciculus to different parts of Broca's area (pars triangularis, pars opercularis) and to the ventral premotor cortex. The potential role of mirror neurons in the right pars opercularis and ventral premotor cortex in aphasia recovery is discussed. PMID:19818232
Martin, Paula I; Naeser, Margaret A; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Baker, Errol H; Pascual-Leone, Alvaro
Transcranial Magnetic Brain Stimulation: Therapeutic Promises and Scientific Gaps
Since its commercial advent in 1985, transcranial magnetic stimulation (TMS), a technique for stimulating neurons in the cerebral cortex through the scalp, safely and with minimal discomfort, has captured the imaginations of scientists, clinicians and lay observers. Initially a laboratory tool for neurophysiologists studying the human motor system, TMS now has a growing list of applications in clinical and basic neuroscience. Although we understand many of its effects at the system level, detailed knowledge of its actions, particularly as a modulator of neural activity, has lagged, due mainly to the lack of suitable non-human models. Nevertheless, these gaps have not blocked the therapeutic application of TMS in brain disorders. Moderate success has been achieved in treating disorders such as depression, where the U.S. Food and Drug Administration has cleared a TMS system for therapeutic use. In addition, there are small, but promising, bodies of data on the treatment of schizophrenic auditory hallucinations, tinnitus, anxiety disorders, neurodegenerative diseases, hemiparesis, and pain syndromes. Some other nascent areas of study also exist. While the fate of TMS as a therapeutic modality depends on continued innovation and experimentation, economic and other factors may be decisive.
Wassermann, Eric M.; Zimmermann, Trelawny
Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation
Background Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a �virtual lesion� in stimulated brain regions, with correspondingly diminished behavioral performance. Methodology/Principal Findings Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary to expectations of a visual deficit, we find that rTMS often improves the discrimination of visual features. For coarse orientation tasks, discrimination of a static stimulus improved consistently following theta-burst stimulation of the occipital lobe. Using a reaction-time task, we found that these improvements occurred throughout the visual field and lasted beyond one hour post-rTMS. Low-frequency (1 Hz) stimulation yielded similar improvements. In contrast, we did not find consistent effects of rTMS on performance in a fine orientation discrimination task. Conclusions/Significance Overall our results suggest that rTMS generally improves or has no effect on visual acuity, with the nature of the effect depending on the type of stimulation and the task. We interpret our results in the context of an ideal-observer model of visual perception.
Waterston, Michael L.; Pack, Christopher C.
Transcranial magnetic stimulation and amyotrophic lateral sclerosis: pathophysiological insights.
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder of the motor neurons in the motor cortex, brainstem and spinal cord. A combination of upper and lower motor neuron dysfunction comprises the clinical ALS phenotype. Although the ALS phenotype was first observed by Charcot over 100 years ago, the site of ALS onset and the pathophysiological mechanisms underlying the development of motor neuron degeneration remain to be elucidated. Transcranial magnetic stimulation (TMS) enables non-invasive assessment of the functional integrity of the motor cortex and its corticomotoneuronal projections. To date, TMS studies have established motor cortical and corticospinal dysfunction in ALS, with cortical hyperexcitability being an early feature in sporadic forms of ALS and preceding the clinical onset of familial ALS. Taken together, a central origin of ALS is supported by TMS studies, with an anterograde transsynaptic mechanism implicated in ALS pathogenesis. Of further relevance, TMS techniques reliably distinguish ALS from mimic disorders, despite a compatible peripheral disease burden, thereby suggesting a potential diagnostic utility of TMS in ALS. This review will focus on the mechanisms underlying the generation of TMS measures used in assessment of cortical excitability, the contribution of TMS in enhancing the understanding of ALS pathophysiology and the potential diagnostic utility of TMS techniques in ALS. PMID:23264687
Vucic, Steve; Ziemann, Ulf; Eisen, Andrew; Hallett, Mark; Kiernan, Matthew C
Multiple effects of repetitive transcranial magnetic stimulation on neuropsychiatric disorders.
Repetitive transcranial magnetic stimulation (rTMS) is a new tool that has been used for the treatment of patients with neuropsychiatric disorders. However, the mechanisms underlying the effects of rTMS are still unclear. We analyzed the changes in mRNA expression in mouse brain that occurred after rTMS with an Affymetrix GeneChip. Following 20days of rTMS, many genes were differentially expressed in the mouse brain. Downregulation of Period 2 and 3 mRNA expression levels and a subsequent decrease in food and water intake were observed. HSP70 mRNA expression levels were upregulated after transient and chronic rTMS. In N2A 150Q cells, an upregulation of HSP70 mRNA and protein levels and subsequent cell-protective effects were observed after chronic rTMS. In addition, dopamine receptor 2 mRNA expression levels were downregulated, and a subsequent decrease in the binding of [(3)H]raclopride was observed. These results indicated that the modulation of several genes may be involved in the therapeutic mechanisms of chronic rTMS for patients with neuropsychiatric disorders. PMID:23524259
Ikeda, Tetsurou; Kurosawa, Masaru; Morimoto, Chikao; Kitayama, Shigeo; Nukina, Nobuyuki
Repetitive transcranial magnetic stimulator with controllable pulse parameters
The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 �s and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.
Peterchev, Angel V.; Murphy, David L.; Lisanby, Sarah H.
Repetitive transcranial magnetic stimulator with controllable pulse parameters.
The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 �s and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency. PMID:21540487
Peterchev, Angel V; Murphy, David L; Lisanby, Sarah H
Design of a dynamic transcranial magnetic stimulation coil system.
To study the brain activity at the whole-head range, transcranial magnetic stimulation (TMS) researchers need to investigate brain activity over the whole head at multiple locations. In the past, this has been accomplished with multiple single TMS coils that achieve quasi whole-head array stimulation. However, these designs have low resolution and are difficult to position and control over the skull. In this study, we propose a new dynamic whole-head TMS mesh coil system. This system was constructed using several sagittal and coronal directional wires. Using both simulation and real experimental data, we show that by varying the current direction and strength of each wire, this new coil system can form both circular coils or figure-eight coils that have the same features as traditional TMS coils. Further, our new system is superior to current coil systems because stimulation parameters such as size, type, location, and timing of stimulation can be dynamically controlled within a single experiment. PMID:24957390
Ge, Sheng; Jiang, Ruoli; Wang, Ruimin; Chen, Ji
Research with Transcranial Magnetic Stimulation in the Treatment of Aphasia
Repetitive transcranial magnetic stimulation (rTMS) has been used to improve language behavior, including naming, in stroke patients with chronic, nonfluent aphasia. Part 1 of this paper reviews functional imaging studies related to language recovery in aphasia. Part 2 reviews the rationale for using rTMS to treat nonfluent aphasia (based on functional imaging); and presents our current rTMS protocol. We present language results from our rTMS studies, and imaging results from overt naming fMRI scans obtained pre- and post- a series of rTMS treatments. Part 3 presents results from a pilot study where rTMS treatments were followed immediately by constraint-induced language therapy. Part 4 reviews our diffusion tensor imaging study that examined possible connectivity of arcuate fasciculus to different parts of Broca�s area (pars triangularis, PTr; pars opercularis, POp); and to ventral premotor cortex (vPMC). The potential role of mirror neurons in R POp and vPMC in aphasia recovery is discussed.
Martin, Paula I; Naeser, Margaret A.; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Baker, Errol H.; Pascual-Leone, Alvaro
Utilizing Transcranial Magnetic Stimulation to Study the Human Neuromuscular System
Transcranial magnetic stimulation (TMS) has been in use for more than 20 years 1, and has grown exponentially in popularity over the past decade. While the use of TMS has expanded to the study of many systems and processes during this time, the original application and perhaps one of the most common uses of TMS involves studying the physiology, plasticity and function of the human neuromuscular system. Single pulse TMS applied to the motor cortex excites pyramidal neurons transsynaptically 2 (Figure 1) and results in a measurable electromyographic response that can be used to study and evaluate the integrity and excitability of the corticospinal tract in humans 3. Additionally, recent advances in magnetic stimulation now allows for partitioning of cortical versus spinal excitability 4,5. For example, paired-pulse TMS can be used to assess intracortical facilitatory and inhibitory properties by combining a conditioning stimulus and a test stimulus at different interstimulus intervals 3,4,6-8. In this video article we will demonstrate the methodological and technical aspects of these techniques. Specifically, we will demonstrate single-pulse and paired-pulse TMS techniques as applied to the flexor carpi radialis (FCR) muscle as well as the erector spinae (ES) musculature. Our laboratory studies the FCR muscle as it is of interest to our research on the effects of wrist-hand cast immobilization on reduced muscle performance6,9, and we study the ES muscles due to these muscles clinical relevance as it relates to low back pain8. With this stated, we should note that TMS has been used to study many muscles of the hand, arm and legs, and should iterate that our demonstrations in the FCR and ES muscle groups are only selected examples of TMS being used to study the human neuromuscular system.
Goss, David A.; Hoffman, Richard L.; Clark, Brian C.
ReaChR: A red-shifted variant of channelrhodopsin enables deep transcranial optogenetic excitation
Channelrhodopsins are used to optogenetically depolarize neurons. We engineered a variant of channelrhodopsin, denoted Red-activatable Channelrhodopsin (ReaChR), that is optimally excited with orange to red light (? ~ 590 to 630 nm) and offers improved membrane trafficking, higher photocurrents, and faster kinetics compared with existing red-shifted channelrhodopsins. Red light is more weakly scattered by tissue and absorbed less by blood than the blue to green wavelengths required by other channelrhodopsin variants. ReaChR expressed in vibrissa motor cortex was used to drive spiking and vibrissa motion in awake mice when excited with red light through intact skull. Precise vibrissa movements were evoked by expressing ReaChR in the facial motor nucleus in the brainstem and illuminating with red light through the external auditory canal. Thus, ReaChR enables transcranial optical activation of neurons in deep brain structures without the need to surgically thin the skull, form a transcranial window, or implant optical fibers.
Lin, John Y.; Knutsen, Per Magne; Muller, Arnaud; Kleinfeld, David; Tsien, Roger Y.
Mood Improvement Following Daily Left Prefrontal Repetitive Transcranial Magnetic Stimulation in Patients With Depression: A Placebo-Controlled Crossover Trial
Objective: Preliminary studies have indicated that daily left prefrontal repetitive transcranial magnetic stimulation might have antidepressant activity. The authors sought to confirm this finding by using a double-blind crossover design. Method: Twelve depressed adults received in random order 2 weeks of active treatment (repetitive transcranial magnetic stimulation, 20 Hz at 80% motor threshold) and 2 weeks of sham treatment. Results:
Mark S. George; Eric M. Wassermann; Tim A. Kimbrell; John T. Little; Wendol E. Williams; Aimee L. Danielson; Benjamin D. Greenberg; Mark Hallett; Robert M. Post
3-dimensional modeling of transcranial magnetic stimulation: Design and application
Over the past three decades, transcranial magnetic stimulation (TMS) has emerged as an effective tool for many research, diagnostic and therapeutic applications in humans. TMS delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this dissertation, we present a thorough examination of the total electric field induced by TMS in air and a realistic head model with clinically relevant coil poses. In the first chapter, a detailed account of TMS coil wiring geometry was shown to provide significant improvements in the accuracy of primary E-field calculations. Three-dimensional models which accounted for the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed primary E-field models were accurate up to the surface of the coil body (within 0.5% of measured values) whereas simple models were often inadequate (up to 32% different from measured). In the second chapter, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3-D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistic head model was used to assess the effect of multiple surfaces on the total E-field. We found that secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes were predominantly between 25% and 45% of the primary E-fields magnitude. The direction of the secondary E-field was primarily in opposition to the primary E-field, however there are some locations (i.e. going from high to low conductivity) where the secondary E-field adds to the primary E-field. Thus the total E-field vector may change in magnitude and direction. These findings show that realistic head geometries should be used when modeling the total E-field. In the third chapter, we addressed the importance of the secondary electric field (E-field) in a realistic head model using the boundary element method at clinically relevant coil positions and orientations (ex. primary motor cortex) during transcranial magnetic stimulation (TMS). The effective E-fields produced at each clinical orientation were then correlated with electromyographic (EMG) recordings using the total E-field with the cortical column cosine model. Some TMS coil orientations led to total E-fields as much as 40% lower than the primary E-fields at sites located on the TMS coil's main axis of stimulation. Effective E-field values at the cortical level, were highly correlated (r = 0.9644, P < 0.01) with EMG responses indicating that both local biological characteristics (such as tissue geometry and electrical conductivity) and the total E-field induced by the TMS coil may provide a means for predicting the optimum coil position/orientation to consistently produce neuronal activations.
Salinas, Felipe Santiago
A structurally detailed finite element human head model for simulation of transcranial magnetic stimulation
Computational studies of the head utilizing finite element models (FEMs) have been used to investigate a wide variety of brain�electromagnetic (EM) field interaction phenomena including magnetic stimulation of the head using transcranial magnetic stimulation (TMS), direct electric stimulation of the brain for electroconvulsive therapy, and electroencephalography source localization. However, no human head model of sufficient complexity for studying the biophysics
Ming Chen; David Jeffery Mogul
Effects of slow repetitive transcranial magnetic stimulation on heart rate variability according to power spectrum analysis
We examined whether repetitive transcranial magnetic stimulation (rTMS) at a low rate could influence autonomic function, specially heart rate variability (HRV) by power spectrum analysis. We studied 16 healthy male volunteers as a stimulation group and 16 others as a sham group. The stimulation group received magnetic stimulations from a circular coil over Cz at a frequency of 0.2 Hz
Takeshi Yoshida; Aihide Yoshino; Yuji Kobayashi; Masayuki Inoue; Keiko Kamakura; Soichiro Nomura
Brain Stimulation Techniques Mechanisms and State of the Art of Transcranial Magnetic Stimulation
Summary: In 1985, Barker et al. built a transcranial magnetic stimulation (TMS) device with enough power to stimulate dorsal roots in the spine. They quickly realized that this machine could likely also noninvasively stimulate the superficial cortex in hu- mans. They waited a while before using their device over a human head, fearing that the TMS pulse might magnetically \\
Mark S. George; Ziad Nahas; F. Andrew Kozel; Xingbao Li; Stewart Denslow; Kaori Yamanaka; Alexander Mishory; Milton J. Foust; Daryl E. Bohning
Repetitive transcranial magnetic stimulation in rats: evidence for a neuroprotective effect in vitro and in vivo
In recent years, repetitive transcranial magnetic stimulation (rTMS) of the human brain has been used as a therapeutic tool in a variety of psychiatric and neurological disorders. However, to understand the mechanisms underlying any potential therapeutic effects, and possible adverse effects, studies are necessary on how magnetic stimuli induced by rTMS interact with central nervous system (CNS) regulation. In the
Anke Post; Marianne B. M�ller; Mario Engelmann; Martin E. Keck
Manifestation of scotomas created by transcranial magnetic stimulation of human visual cortex
Reduced visual performance under transcranial magnetic stimulation (TMS) of human visual cortex demonstrates suppression whose spatial extent is not directly visible. We created an artificial scotoma (region missing from a visual pattern) to directly visualize the location, size and shape of the TMS-induced suppression by following a large-field, patterned, visual stimulus with a magnetic pulse. The scotoma shifted with coil
Shinsuke Shimojo; Yukiyasu Kamitani
Locating the Motor Cortex on the MRI with Transcranial Magnetic Stimulation and PET
Transcranial magnetic stimulation with a focal coil was used to map the cortical representation of a hand muscle in four healthy subjects. In each subject, the three-dimensional locations of the magnetic stimulation positions and about 400 positions on the surface of the head were digitized. The amplitude-weighted center of gravity of each subject's map was found, and a line perpendicular
Eric M. Wassermann; Binseng Wang; Thomas A. Zeffiro; Norihiro Sadato; Alvaro Pascual-Leone; Camilo Toro; Mark Hallett
Objective: In this review we trace some of the mayor developments in the use of Transcranial magnetic stimulation (TMS) as a technique for the investigation of cognitive neuroscience and its application as an assessment and rehabilitation tool in some psychiatric and neurological disorders. Technical aspects and safety studies in animal and humans of the magnetic stimulation are also reviewed. Development:
Beatriz Calvo Merino; Patrick Haggard
Transcranial magnetic stimulation in cognitive neuroscience � virtual lesion, chronometry, and functional connectivity
Fifteen years after its introduction by Anthony Barker, transcranial magnetic stimulation (TMS) appears to be �coming of age� in cognitive neuroscience and promises to reshape the way we investigate brain�behavior relations. Among the many methods now available for imaging the activity of the human brain, magnetic stimulation is the only technique that allows us to interfere actively with brain function.
Alvaro Pascual-Leone; Vincent Walsh; John Rothwell
Combination rapid transcranial magnetic stimulation in treatment refractory depression
High frequency (>1 Hz) repetitive transcranial magnetic stimulation (rTMS) applied to the left prefrontal cortex and low frequency (?1 Hz) rTMS applied to the right prefrontal cortex have shown antidepressant effects. However, the clinical significance of these effects has often been modest. It was hypothesized that a combination of these two techniques might act synergistically and result in more clinically relevant antidepressant effects. Sixty-two subjects with treatment-resistant major depression (an average of 8 failed medication trials) were randomized to receive combination right low frequency (1 Hz)/left high frequency (10 Hz) rTMS over the dorsolateral prefrontal cortex at 110% of the motor threshold vs sham rTMS. Subjects were treated for 2 weeks (10 weekday sessions) and received 1600 stimulations during each treatment session. Subjects receiving combination treatment were further randomized to receive different orders of treatment: right low frequency first (Slow Right) vs left high frequency first (Fast Left). There were no statistical differences in the active vs sham treatment arms in the primary outcome variable, the Hamilton Depression Rating Scale (HDRS). However compared with subjects in the Sham and Slow Right arms, there was a trend for subjects in the Fast Left arm to show improvement in the HDRS, the Beck Depression Inventory, and the Brief Psychotic Rating Scale with increased number of treatments. The Fast Left arm also showed significant improvement in both blinded clinician and self-ratings of global improvement. These differences were hypothesized to be due to the decreased number of failed medication trials for subjects in Fast Left arm. Neuropsychological performance was not significantly different between the sham and active rTMS arms. Future studies should increase the number of treatment sessions and focus on subjects with moderate treatment resistance.
McDonald, William M; Easley, Kirk; Byrd, Eve H; Holtzheimer, Paul; Tuohy, Shannon; Woodard, John L; Beyer, Kimberly; Epstein, Charles M
Repetitive transcranial magnetic stimulation influences mood in healthy male volunteers.
The influence of repetitive transcranial magnetic stimulation (rTMS) on mood in healthy people is uncertain, as former studies show divergent results. Previous studies in healthy volunteers focused exclusively on the immediate effect of a single session of rTMS. In contrast the aim of this randomised sham-controlled study was to analyse the influence on mood of a series of 9 High Frequency (HF) rTMS stimulations of the left dorsolateral prefrontal cortex (DLPFC). 44 young healthy male volunteers were randomly assigned to receive 9 sessions of active HF-rTMS (n�=�22) or sham rTMS (n�=�22) over the left DLPFC. Each session in the active group consisted of 15 trains of 25�Hz starting with 100% of motor threshold. Sham stimulation was performed following the same protocol, but using a sham coil. The variables of interest were the Beck Depression Inventory (BDI) and six Visual Analogue Scales (VAS) which quantified "mood", "enjoyment" and "energy". We found a significant reduction of the BDI sum score in the active group (GLM, p�<�0.001) whereas no significant changes of the BDI sum score were caused by sham stimulation (GLM, p�=�0.109). The BDI single item analyses revealed within and between group differences supporting the modifying effect of rTMS on BDI. According to the employed VAS we did not find significant differences caused by active or sham stimulation in five of six VAS. In the VAS labelled lively/gloomy the active group was found to be more "gloomy" (p�=�0.0111) immediately after stimulation. Our data show that a 9-day long series of HF-rTMS of the left DLPFC improves mood, analysed by BDI in healthy young men, whereas no significant long-term changes were found in VAS. PMID:21397253
Schaller, Gerd; Lenz, Bernd; Friedrich, Kerstin; Dygon, Dominika; Richter-Schmidinger, Tanja; Jacobi, Andrea; Mueller, Sandra E; Maih�fner, Christian; Sperling, Wolfgang; Kornhuber, Johannes
Repetitive transcranial magnetic stimulation in restless legs syndrome: preliminary results.
Our aim was to compare the effect of high-frequency repetitive transcranial magnetic stimulation (rTMS) over supplementary motor area with that of sham stimulation in restless legs syndrome (RLS). In this prospective study, patients were randomly assigned to either real stimulation group (11 patients), or sham stimulation group (8 patients) in a double-blinded fashion. Five patients, who were initially in the sham stimulation group, received real stimulation 1�month after the sham stimulation. One session of intervention was performed once every 3�days and total of ten sessions were done in each group. The International RLS-Rating Scale (IRLS-RS) was assessed at baseline and after 5th and 10th sessions in both groups and also in five patients in whom both sham and real stimulation were performed. A statistically significant difference was seen in the IRLS scores between real (n�=�11) and sham stimulation (n�=�8) after 5th and 10th sessions. The real stimulation significantly improved the IRLS-RS scores although they were unaffected by the sham stimulation. In five patients, in whom both sham and real stimulation were performed, a statistically significant improvement was seen in the IRLS-RS scores with the real stimulation and a statistically significant difference was seen in the IRLS scores between real and sham stimulation after 10th session. In conclusion, this method is safe and non-invasive, and the results of this pilot study may support that rTMS has the potential to be used in the treatment of RLS, which should be verified in larger series. PMID:24487701
Altunrende, Burcu; Yildiz, Serpil; Cevik, Ayse; Yildiz, Nebil
Transcranial direct current stimulation and simultaneous functional magnetic resonance imaging.
Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that uses weak electrical currents administered to the scalp to manipulate cortical excitability and, consequently, behavior and brain function. In the last decade, numerous studies have addressed short-term and long-term effects of tDCS on different measures of behavioral performance during motor and cognitive tasks, both in healthy individuals and in a number of different patient populations. So far, however, little is known about the neural underpinnings of tDCS-action in humans with regard to large-scale brain networks. This issue can be addressed by combining tDCS with functional brain imaging techniques like functional magnetic resonance imaging (fMRI) or electroencephalography (EEG). In particular, fMRI is the most widely used brain imaging technique to investigate the neural mechanisms underlying cognition and motor functions. Application of tDCS during fMRI allows analysis of the neural mechanisms underlying behavioral tDCS effects with high spatial resolution across the entire brain. Recent studies using this technique identified stimulation induced changes in task-related functional brain activity at the stimulation site�and also in more distant brain regions, which were associated with behavioral improvement. In addition, tDCS administered during resting-state fMRI allowed identification of widespread changes in whole brain functional connectivity. Future studies using this combined protocol should yield new insights into the mechanisms of tDCS action in health and disease and new options for more targeted application of tDCS in research and clinical settings. The present manuscript describes this novel technique in a step-by-step fashion, with a focus on technical aspects of tDCS administered during fMRI. PMID:24796646
Meinzer, Marcus; Lindenberg, Robert; Darkow, Robert; Ulm, Lena; Copland, David; Fl�el, Agnes
High permeability cores to optimize the stimulation of deeply located brain regions using transcranial magnetic stimulation
Efficient stimulation of deeply located brain regions with transcranial magnetic stimulation (TMS) poses many challenges, arising from the fact that the induced field decays rapidly and becomes less focal with depth. We propose a new method to improve the efficiency of TMS of deep brain regions that combines high permeability cores, to increase focality and field intensity, with a coil specifically designed to induce a field that decays slowly with increasing depth. The performance of the proposed design was investigated using the finite element method to determine the total electric field induced by this coil/core arrangement on a realistically shaped homogeneous head model. The calculations show that the inclusion of the cores increases the field's magnitude by as much as 25% while also decreasing the field's decay with depth along specific directions. The focality, as measured by the area where the field's norm is greater than 1/\\sqrt 2 of its maximum value, is also improved by as much as 15% with some core arrangements. The coil's inductance is not significantly increased by the cores. These results show that the presence of the cores might make this specially designed coil even more suited for the effective stimulation of deep brain regions.
Salvador, R.; Miranda, P. C.; Roth, Y.; Zangen, A.
[Therapeutic application of repetitive transcranial magnetic stimulation for major depression].
It has been reported that approximately one third of patients with major depression are medication-resistant. In spite of partial responsiveness to antidepressants, most of the medication-resistant patients remain incompletely remitted without successful social reintegration. Symptom severity could be mild to moderate for many of them due to the incomplete remission, and, thus, electroconvulsive therapy is not applicable for them. However, they usually feel some difficulty performing cognitive behavioral therapy or social rehabilitation training due to residual symptoms such as thought inhibition and hypobulia. Under such conditions, those patients are longing for treatment options complementary to antidepressants, for less painful social reintegration. In October 2008, the Food and Drug Administration (FDA) of the United States finally approved repetitive Transcranial Magnetic Stimulation (rTMS) for medication-resistant patients with major depression. The main reason for the FDA approval was that rTMS had shown similar effectiveness (effect size around 0.39 in a recent meta-analysis) to antidepressants for medication-resistant patients without serious adverse effects. TMS is a brain stimulation methodology employing magnetic energy which can penetrate the skull bone without energy decay, and, thus, eddy currents induced by TMS can stimulate cerebral cortices effectively and locally. When TMS is repetitively delivered over several hundreds of pulses within a session, stimulation effects can be observed beyond the stimulation period as aftereffects. Moreover, when a daily rTMS session is repeated over several weeks, rTMS could have antidepressant effects. Clinical trials of rTMS for depression have employed two kinds of rTMS protocol of high-frequency (facilitatory) rTMS over the left Dorsolateral Prefrontal Cortex (DLPFC) and low-frequency (inhibitory) rTMS over the right DLPFC. Although the antidepressant action of rTMS over DLPFC has not been fully elucidated, the neuronal level hypothesis includes the induction of neuroplasticity and activation of the dopamine system, and the neuronal circuitry level hypothesis includes the activation of the left DLPFC and inhibition of the right DLPFC and (para) limbic system such as the subgenual cingulate cortex and amygdala. On the therapeutic application of rTMS in clinical psychiatry, neuroethics and low invasiveness should be fully considered along with a negative history of punitive electroconvulsive therapy and prefrontal lobotomy. It is important to investigate the neurobiological mechanism of rTMS treatment and to place rTMS in a suitable position within comprehensive treatment algorithms of major depression. PMID:23367835
Nakamura, Motoaki
Corticomotor control of the genioglossus in awake OSAS patients: a transcranial magnetic stimulation study
BACKGROUND: Upper airway collapse does not occur during wake in obstructive sleep apnea patients. This points to wake-related compensatory mechanisms, and possibly to a modified corticomotor control of upper airway dilator muscles. The objectives of the study were to characterize the responsiveness of the genioglossus to transcranial magnetic stimulation during respiratory and non-respiratory facilitatory maneuvers in obstructive sleep apnea patients,
Wei Wang; Thomas Similowski
Effects of transcranial magnetic stimulation on auditory attention: An electroencephalographic study
Noninvasive brain stimulation became very popular recently. Electroencephalographic (EEG) responses evoked by transcranial magnetic stimulation (TMS) gain more and more interest for basic neurophysiological research and possibly diagnostic purposes. In addition, the effect of TMS to the attentional processes has been reported in many studies. In this paper, the effect of TMS on auditory attention in the EEG is discussed
Arief R. Harris; Karsten Schwerdtfeger; Yin Fen Low; Daniel J. Strauss
Transcranial Magnetic Stimulation and Antidepressive Drugs Share Similar Cellular Effects in Rat Hippocampus
Transcranial magnetic stimulation (TMS) has been proposed as a safe and efficient treatment of human clinical depression. Although its antidepressive mechanism of action remained unknown, our previous studies indicate that TMS has a long-lasting effect on neuronal excitability in the hippocampus. We now compare the effects of chronic TMS with those of the antidepressant drugs desipramine and mianserin. The three
Y. Levkovitz; N. Grisaru; M. Segal
Studies in Cognition: The Problems Solved and Created by Transcranial Magnetic Stimulation
The application of transcranial magnetic stimulation (TMS) to investigate important questions in cognitive neuroscience has increased considerably in the last few years. TMS can provide substantial insights into the nature and the chronometry of the computations performed by specific cortical areas during various aspects of cognition. However, the use of TMS in cognitive studies has many potential perils and pitfalls.
E. M. Robertson; H. Th�oret; A. Pascual-Leone
The Role of the Dorsolateral Prefrontal Cortex in Bimodal Divided Attention: Two Transcranial Magnetic Stimulation Studies
The neural processes underlying the ability to divide attention between multiple sensory modalities remain poorly understood. To investigate the role of the dorsolateral prefrontal cortex (DLPFC) in bimodal divided attention, we completed two repetitive transcranial magnetic stimulation (rTMS) studies. We tested the hypothesis that the DLPFC is necessary in the ability to divide attention across modalities. This hypothesis originated as
Jennifer Adrienne Johnson; Antonio P. Strafella; Robert J. Zatorre
Overclaiming and the medial prefrontal cortex: A transcranial magnetic stimulation study
The tendency to claim more knowledge than one actually has is common and well documented; however, little research has focused on the neural mechanisms that underlie this phenomenon. The goal of the present study was to investigate the cortical correlates of overclaiming. Transcranial magnetic stimulation (TMS) was delivered to the medial prefrontal cortex (MPFC), supplementary motor area, and precuneus during
Franco Amati; Hanna Oh; Virginia S. Y. Kwan; Kelly Jordan; Julian Paul Keenan
Long-Term Effects of Transcranial Magnetic Stimulation on Hippocampal Reactivity to Afferent Stimulation
Transcranial magnetic stimulation (TMS) has become a prom- ising treatment of affective disorders in humans, yet the neuro- nal basis of its long-lasting effects in the brain is still unknown. We studied acute and lasting effects of TMS on reactivity of the rat hippocampus to stimulation of the perforant path. Applica- tion of TMS to the brain of the anesthetized
Yechiel Levkovitz; Julia Marx; Nimrod Grisaru; Menahem Segal
Influence of transcranial magnetic stimulation on the execution of memorised sequences of saccades in man
Memorised sequences of saccades are cortically controlled by the supplementary motor area (SMA), as shown in animal experiments and in humans with isolated SMA lesions. We applied transcranial magnetic stimulation (TMS) in eight healthy subjects executing memorised sequences of saccades. Sequences of three targets were presented. Then, upon a go-signal, the subjects had to execute the appropriate sequences. Ten to
R. M. M�ri; K. M. R�sler; C. W. Hess
Transcranial Magnetic Stimulation in the investigation and treatment of schizophrenia: a review
Transcranial Magnetic Stimulation (TMS) is a non-invasive method of stimulating the brain that is increasingly being used in neuropsychiatric research and clinical psychiatry. This review examines the role of TMS in schizophrenia research as a diagnostic and a therapeutic resource. After a brief overview of TMS, we describe the application of TMS to schizophrenia in studies of cortical excitability and
H. Magnus Haraldsson; Fabio Ferrarelli; Ned H. Kalin; Giulio Tononi
The effect of transcranial magnetic stimulation on the latencies of vertical saccades
In this study, we investigated the effect of transcranial magnetic stimulation (TMS) over the right posterior parietal cortex (PPC) on the latency of two different types of visually-guided vertical saccades: reflexive saccades triggered by the sudden onset of a target, and saccades towards target locations known in advance. For this reason, we used two oculomotor tasks: a gap and a
A. Tzelepi; Q. Yang; Z. Kapoula
Transcranial magnetic stimulation and the motor learning-associated cortical plasticity
It has been well established that repetitive motor performance and skill learning alter the functional organization of human corticomotoneuronal system. Over the past decade, transcranial magnetic stimulation (TMS) has helped to demonstrate motor practice and learning-related changes in corticomotoneuronal excitability and representational plasticity. It has also provided some insights into the mechanisms underlying such plasticity. TMS-derived indices show that motor
Milos Ljubisavljevic
Navigated transcranial magnetic stimulation of the primary somatosensory cortex impairs perceptual processing of tactile temporal discrimination
Previous studies indicate that transcranial magnetic stimulation (TMS) with biphasic pulses applied approximately over the primary somatosensory cortex (S1) suppresses performance in vibrotactile temporal discrimination tasks; these previous results, however, do not allow separating perceptual influence from memory or decision-making. Moreover, earlier studies using external landmarks for directing biphasic TMS pulses to the cortex do not reveal whether the changes
Henri Hannula; Tuomas Neuvonen; Petri Savolainen; Taru Tukiainen; Oili Salonen; Synn�ve Carlson; Antti Pertovaara
Chronometry of parietal and prefrontal activations in verbal working memory revealed by transcranial magnetic stimulation
We explored the temporal dynamics of parietal and prefrontal cortex involvement in verbal working memory employing single-pulse transcranial magnetic stimulation (TMS). In six healthy volunteers the left or right inferior parietal and prefrontal cortex was stimulated with the aid of a frameless stereotactic system. TMS was applied at 10 different time points 140�500 ms into the delay period of a
F. M Mottaghy; M Gangitano; B. J Krause; A Pascual-Leone
Facilitating Effect of 15Hz Repetitive Transcranial Magnetic Stimulation on Tactile Perceptual Learning
Recent neuroimaging studies have revealed that tactile perceptual learning can lead to substantial reorganizational changes of the brain. We report here for the first time that combining high-frequency (15 Hz) repetitive transcranial magnetic stimulation (rTMS) over the primary somatosensory cortex (SI) with tactile discrimination training is capable of facilitating operant perceptual learning. Most notably, increasing the excitability of SI by
Ahmed A. Karim; Anne Sch�ler; Yiwen Li Hegner; Eva Friedel; Ben Godde
Anisotropy in the visual cortex investigated by neuronavigated transcranial magnetic stimulation
Responses to transcranial magnetic stimulation (TMS) of the motor cortex depend on the direction of the induced current with an optimum perpendicular to the orientation of the precentral gyrus. Little is known about anisotropy in other cortical regions. We measured phosphene thresholds in the visual cortex using a frameless neuronavigation system. Comparing horizontal and vertical current orientation as well as
Thomas Kammer; Michael Vorwerg; B�rbel Herrnberger
New graphical method to measure silent periods evoked by transcranial magnetic stimulation
Objectives: Manual methods of measuring duration of cortical silent periods (CSP) evoked by transcranial magnetic stimulation (TMS) depend upon subjective visual estimation of onset and offset. Because of this, the measurements are susceptible to poor rater reliability. We describe a graphical method to measure silent periods with greater precision. The statistical process underlying this new method is simple and particularly
M. A Garvey; U Ziemann; D. A Becker; C. A Barker; J. J Bartko
Effects of Right Parietal Transcranial Magnetic Stimulation on Object Identification and Orientation Judgments
We investigated the role played by the right parietal lobe in object identification and the ability to interpret object orien- tation, using transcranial magnetic stimulation (TMS) to mo- mentarily interfere with ongoing cortical activity. Short trains of TMS pulses (12 Hz) were applied to a site overlying the right intraparietal sulcus\\/inferior parietal lobe while subjects per- formed either object identification
Irina M. Harris; Claire T. Benito; Manuela Ruzzoli; Carlo Miniussi
Is there a future for therapeutic use of transcranial magnetic stimulation?
Repetitive transcranial magnetic stimulation (rTMS) has in recent years been used to explore therapeutic opportunities in a bewildering variety of conditions. Although there is good evidence that this technique can modify cortical activity, the rationale for its use in many of the conditions investigated so far is not clear. Here we discuss the effects of rTMS in healthy subjects and
Michael C. Ridding; John C. Rothwell
Neuronavigated repetitive transcranial magnetic stimulation in patients with tinnitus: a short case series
BackgroundClinical as well as neurophysiological and neuroimaging data suggest that chronic tinnitus resembles neuropsychiatric syndromes characterized by focal brain activation. Low-frequency repetitive transcranial magnetic stimulation (rTMS) has been proposed as an efficient method in treating brain hyperexcitability disorders by reducing cortical excitability.
Peter Eichhammer; Berthold Langguth; J�rg Marienhagen; Tobias Kleinjung; G�ran Hajak
Left frontal transcranial magnetic stimulation reduces contralesional extinction in patients with unilateral right brain damage
Summary It has been demonstrated previously that transcranial magnetic stimulation (TMS) of the sensorimotor cortex can induce transient suppression of the perception of cutaneous near-threshold stimuli from fingers of the contralateral hand in normal individuals. One explanation accounting for deficits in the exploration of contralateral space following a unilateral hemispheric lesion refers to a loss of the normal interhemispheric balance,
M. Oliveri; P. M. Rossini; R. Traversa; P. Cicinelli; M. M. Filippi; P. Pasqualetti; F. Tomaiuol; C. Caltagirone
A new method for reproducible coil positioning in transcranial magnetic stimulation mapping
A new method is presented for mapping the motor cortex by transcranial magnetic stimulation in which the position of the stimulation coil on the scalp is measured using a 3D digitizer. The reproducibility of the method was tested by mapping 3 times the left abductor digiti minimi of 6 right-handed subjects and calculating the position of the centre of gravity
Pedro Cavaleiro Miranda; Mamede de Carvalho; Isabel Concei��o; M. L. Sales Luis; Eduardo Ducla-Soares
Recording an identified pyramidal volley evoked by transcranial magnetic stimulation in a conscious macaque monkey
A descending volley in response to non-invasive transcranial magnetic stimulation has been recorded from the pyramidal tract in a conscious monkey and identified by means of a collision test. The short latency of the earliest wave was inconsistent with a trans-synaptically mediated activation of pyramidal tract neurones. Considerable variability in the size of this wave was seen in response to
Stuart N. Baker; Etienne Olivier; Roger N. Lemon
Transcranial magnetic stimulation highlights the sensorimotor side of empathy for pain
Pain is intimately linked with action systems that are involved in observational learning and imitation. Motor responses to one's own pain allow freezing or escape reactions and ultimately survival. Here we show that similar motor responses occur as a result of observation of painful events in others. We used transcranial magnetic stimulation to record changes in corticospinal motor representations of
Alessio Avenanti; Domenica Bueti; Gaspare Galati; Salvatore M Aglioti
Transcranial magnetic stimulation (TMS) in controlled treatment studies: are some �sham� forms active?
Background: Carefully designed controlled studies are essential in further evaluating the therapeutic efficacy of transcranial magnetic stimulation (TMS) in psychiatric disorders. A major methodological concern is the design of the �sham� control for TMS. An ideal sham would produce negligible cortical stimulation in conjunction with a scalp sensation akin to real treatment. Strategies employed so far include alterations in the
Colleen K. Loo; Janet L. Taylor; Simon C. Gandevia; Benjamin N. McDarmont; Philip B. Mitchell; Perminder S. Sachdev
Spatial neglect in near and far space investigated by repetitive transcranial magnetic stimulation
Summary Localized repetitive transcranial magnetic stimulation was used to disrupt visuospatial perception in the near and far space of six healthy volunteer subjects. In addi- tion to the baseline condition, they were stimulated over the right posterior parietal cortex, the right or left dorsal occipital cortex or the right ventral occipital cortex, during the brief presentation of a transected horizontal
Otto Bjoertomt; Alan Cowey; Vincent Walsh
Acute Remapping within the Motor System Induced by Low Frequency Repetitive Transcranial Magnetic Stimulation
Repetitive transcranial magnetic stimulation (rTMS) of human primary motor cortex (M1 ) changes cortical excitability at the site of stimulation and at distant sites without affecting simple motor performance. The aim of this study was to explore how rTMS changes regional excitability and how the motor system compensates for these changes. Using functional brain imaging, activation was mapped at rest
Lucy Lee; Hartwig R. Siebner; James B. Rowe; Vincenzo Rizzo; John C. Rothwell; Richard S. J. Frackowiak; Karl J. Friston
Transcranial magnetic stimulation of left temporoparietal cortex in three patients reporting hallucinated �voices�
Background: Prior studies suggest that auditory hallucinations of �voices� arise from activation of speech perception areas of the cerebral cortex. Low frequency transcranial magnetic stimulation (TMS) can reduce cortical activation.Methods: We have studied three schizophrenic patients reporting persistent auditory hallucinations to determine if low frequency TMS could curtail these experiences. One hertz stimulation of left temporoparietal cortex was compared with
Ralph E Hoffman; Nashaat N Boutros; Robert M Berman; Elizabeth Roessler; Aysenil Belger; John H Krystal; Dennis S Charney
Cerebral Visual Motion Blindness: Transitory Akinetopsia Induced by Transcranial Magnetic Stimulation of Human Area V5
The perception of visual motion can be selectively and reversibly compromised by transcranial magnetic stimulation (TMS) of a small region of cortex, roughly 1 cm in diameter and corresponding in position to human area V5. The reversible inactivation of a small and specialized visual area which receives its predominant input from area V1 and sends a powerful return (re-entrant) input
G. Beckers; V. Homberg
Functional Connectivity of Human Premotor and Motor Cortex Explored with Repetitive Transcranial Magnetic Stimulation
Connections between the premotor cortex and the primary motor cortex are dense and are important in the visual guidance of arm movements. We have shown previously that it is possi- ble to engage these connections in humans and to measure the net amount of inhibition\\/facilitation from premotor to motor cortex using single-pulse transcranial magnetic stimulation (TMS). The aim of this
A. Munchau; B. R. Bloem; K. Irlbacher; M. R. Trimble; J. C. Rothwell
Evoked potentials and transcranial magnetic stimulation in migraine: published data and viewpoint on their pathophysiologic significance
Migraine is a disorder in which central nervous sytem dysfunction might play a pivotal role. Electroneurophysiology seems thus particularly suited to study its pathophysiology. We have extensively reviewed evoked potential and transcranial magnetic stimulation studies performed in migraineurs in order to identify their pathophysiologic significance. Publications available to us were completed by a Medline search. Retrieved and personal data were
Jean Schoenen; Anna Ambrosini; Peter S S�ndor; Alain Maertens de Noordhout
Evaluating frontal and parietal contributions to spatial working memory with repetitive transcranial magnetic stimulation
Functional neuroimaging studies have produced contradictory data about the extent to which specific regions of the frontal and the posterior parietal cortices contribute to the retention of information in spatial working memory. We used high frequency repetitive transcranial magnetic stimulation (rTMS) to assess the necessity for the short-term retention of spatial information of brain areas identified by previous functional imaging
Massihullah Hamidi; Giulio Tononi; Bradley R. Postle
Noninvasive techniques for probing neurocircuitry and treating illness: vagus nerve stimulation (VNS), transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS)
Although the preceding chapters discuss much of the new knowledge of neurocircuitry of neuropsychiatric diseases, and an invasive approach to treatment, this chapter describes and reviews the noninvasive methods of testing circuit-based theories and treating neuropsychiatric diseases that do not involve implanting electrodes into the brain or on its surface. These techniques are transcranial magnetic stimulation, vagus nerve stimulation, and
Mark S George; Gary Aston-Jones
Motor cortex-induced plasticity by noninvasive brain stimulation: a comparison between transcranial direct current stimulation and transcranial magnetic stimulation.
The aim of this study was to test and compare the effects of a within-subject design of repetitive transcranial magnetic stimulation (rTMS) [coupled with sham transcranial direct current stimulation (tDCS)] and tDCS (coupled with sham rTMS) on the motor cortex excitability and also compare the results against sham tDCS/sham rTMS. We conducted a double-blinded, randomized, sham-controlled, cross-over trial. Eleven right-handed, healthy individuals (five women, mean age: 39.8 years, SD 13.4) received the three interventions (cross-over design) in a randomized order: (a) high-frequency (HF) rTMS (+sham tDCS), (b) anodal tDCS (+sham rTMS), and (c) sham stimulation (sham rTMS+sham tDCS). Cortical excitability measurements [motor threshold, motor evoked potential (MEP), intracortical facilitation and inhibition, and transcallosal inhibition] and motor behavioral assessments were used as outcome measures. Between-group analysis of variance showed that MEP amplitude after HF rTMS was significantly higher than MEP amplitude after anodal tDCS (P=0.001). Post-hoc analysis showed a significant increase in MEP amplitude after HF rTMS (25.3%, P=0.036) and a significant decrease in MEP amplitude after anodal tDCS (-32.7%, P=0.001). There was a similar increase in motor function as indexed by Jebsen-Taylor Hand Function Test in the two active groups compared with sham stimulation. In conclusion, here, we showed that although both techniques induced similar motor gains, they induce opposing results in cortical excitability. HF rTMS is associated with an increase in corticospinal excitability, whereas 20 min of tDCS induces the opposite effect. We discuss potential implications of these results to future clinical experiments using rTMS or tDCS for motor function enhancement. PMID:24100412
Simis, Marcel; Adeyemo, Bamidele O; Medeiros, Liciane F; Miraval, Forella; Gagliardi, Rubens J; Fregni, Felipe
Pressure Pain Thresholds Increase after Preconditioning 1 Hz Repetitive Transcranial Magnetic Stimulation with Transcranial Direct Current Stimulation
Background The primary motor cortex (M1) is an effective target of non-invasive cortical stimulation (NICS) for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. Objective Here we investigate whether transcranial direct current stimulation (tDCS) primed 1 Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. Method 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs) from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST) through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. Results Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (p<0.001) with a parallel increase in pressure pain thresholds (p<0.01). In contrast, anodal tDCS-primed 1 Hz-rTMS resulted in a corresponding decrease in cortical excitability (p<0.05), with no significant effect on pressure pain. Conclusion This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia.
Moloney, Tonya M.; Witney, Alice G.
Transcranial magnetic stimulation (TMS) is a well-known technique to study brain function. Location of TMS points can be visualized on the subject's Magnetic Resonance Im- age (MRI). However inter-subject comparison is possible only after a normalization i.e. a transformation of the stimu- lation points to a reference atlas image. Here, we propose a generic and automatic image pro- cessing pipe-line
D. Zosso; Q. Noirhomme; M. Davare; B. Macq; E. Olivier; J. Thiran; M. De Craene
Effects of left frontal transcranial magnetic stimulation on depressed mood, cognition, and corticomotor threshold
Background: The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation.Methods: We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in
William J Triggs; Karin J. M McCoy; Richard Greer; Fabian Rossi; Dawn Bowers; Sarah Kortenkamp; Stephen E Nadeau; Kenneth M Heilman; Wayne K Goodman
Magnetic transcranial stimulation at intensities below active motor threshold activates intracortical inhibitory circuits
A magnetic transcranial conditioning stimulus given over the motor cortex at intensities below threshold for obtaining electromyographical\\u000a (EMG) responses in active hand muscles can suppress responses evoked in the same muscles at rest by a suprathreshold magnetic\\u000a test stimulus given 1�5 ms later. In order to define the mechanism of this inhibitory effect, we recorded descending volleys\\u000a produced by single
V. Di Lazzaro; D. Restuccia; A. Oliviero; P. Profice; L. Ferrara; A. Insola; P. Mazzone; P. Tonali; J. C. Rothwell
Focal transcranial magnetic stimulation and response bias in a forced-choice task
The effects of transcranial magnetic stimulation were studied on the performance of a warned, forced-choice response time task by normal adults. The task consisted of extension of the index finger in response to the click produced by the discharge of the magnetic coil (go-signal). The subjects were asked to choose the right or left finger only after the go-signal was
J. P. Brasil-neto; A Pascual-Leone; J Valls-Sol�; L G Cohen; M Hallett
High frequency transcranial magnetic stimulation mimics the effects of ECS in upregulating astroglial gene expression in the murine CNS
The present study evaluates the consequences of high frequency (25 hz) trans-cranial magnetic stimulation on the expression of glial fibrillary acidic protein (GFAP) in the murine CNS. Trains of transcranial magnetic stimulation (1�30 trains at 25 Hz, 10 s duration) were delivered to mice via 5-cm diameter round coils. The stimulation produced stimulus-locked motor responses but did not elicit behavioral
Minoru Fujiki; Oswald Steward
Latency of changes in spinal motoneuron excitability evoked by transcranial magnetic brain stimulation in spinal cord injured individuals
Objectives: To examine the basis for delay in the excitatory effects of transcranial magnetic stimulation (TMS) of motor cortex on motoneuron pools of muscles left partially-paralyzed by traumatic spinal cord injury (SCI).Methods: The effect of subthreshold transcranial magnetic stimulation (TMS) on just-suprathreshold H-reflex amplitude was examined in subjects (n=10) with incomplete cervical SCI, and in able-bodied (AB) subjects (n=20) for
Natalia Alexeeva; James G Broton; Blair Calancie
Treatment and physiology in Parkinson's disease and dystonia: using transcranial magnetic stimulation to uncover the mechanisms of action.
Transcranial magnetic stimulation (TMS) has served as an important technological breakthrough in the field of the physiology of movement disorders over the last three decades. TMS has grown popular owing to the ease of application as well as its painless and noninvasive character. The technique has provide important insights into understanding the pathophysiology of movement disorders, particularly Parkinson's disease and dystonia. The basic applications have included the study of motor cortex excitability, functioning of excitatory and inhibitory circuits, study of interactions between sensory and motor systems, and the plasticity response of the brain. TMS has also made important contributions to understanding the response to treatments such as dopaminergic medications, botulinum toxin injections, and deep brain stimulation surgery. This review summarizes the knowledge gained to date with TMS in Parkinson's disease and dystonia, and highlights the current challenges in the use of TMS technology. PMID:24771105
Wagle Shukla, Aparna; Vaillancourt, David E
Short-term reliability of transcranial magnetic stimulation motor maps in upper limb amputees.
The aim of this study was to verify the short-term reliability of transcranial magnetic stimulation (TMS) parameters for a damaged stump muscle in upper-limb amputees (n=6). The motor threshold, response latency and map center of gravity in the mediolateral plane showed good reliability, whereas the map volume measure was less stable. The stability of most TMS measures across time supports the use of TMS in studying cortical plasticity in amputees. PMID:21393001
H�tu, S; Gagn�, M; Reilly, K T; Mercier, C
Responses of the diaphragm to transcranial magnetic stimulation during wake and sleep in humans
The human ventilation depends on bulbospinal and corticospinal commands. This study assessed their interactions in five healthy volunteers (two men, age 25�35) through the description of diaphragm and abductor pollicis brevis (APB) motor potentials (DiMEPs, abpMEPs) evoked by transcranial magnetic stimulation (TMS) during relaxed expiration and tidal inspiration and during wake and sleep. NREM decreased corticospinal excitability and REM further
Selma Mehiri; Christian Straus; Isabelle Arnulf; Val�rie Attali; Marc Zelter; Jean-Philippe Derenne; Thomas Similowski
A Transcranial Magnetic Stimulator Inducing Near-Rectangular Pulses With Controllable Pulse Width (cTMS)
A novel transcranial magnetic stimulation (TMS) device with controllable pulse width (PW) and near-rectangular pulse shape (cTMS) is described. The cTMS device uses an insulated gate bipolar transistor (IGBT) with appropriate snubbers to switch coil currents up to 6 kA, enabling PW control from 5 mus to over 100 mus. The near-rectangular induced electric field pulses use 2%-34% less energy
Angel V. Peterchev; Reza Jalinous; Sarah H. Lisanby
Repetitive transcranial magnetic stimulator with controllable pulse parameters (cTMS)
We describe a novel transcranial magnetic stimulation (TMS) device that uses a circuit topology incorporating two energy-storage capacitors and two insulated-gate bipolar transistors (IGBTs) to generate near-rectangular electric field (E-field) pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable-pulse-parameter TMS (cTMS) device can induce E-field pulses with phase widths of 5-200 ?s and positive\\/negative phase
Angel V. Peterchev; David L. Murphy; Sarah H. Lisanby
Depression in Parkinson�s disease: brainstem midline alteration on transcranial sonography and magnetic resonance imaging
Recent studies using transcranial sonography (TCS) have provided evidence of alterations in the mesencephalic midline structures\\u000a in patients with unipolar depression and depression in Parkinson�s disease (PD), suggesting an involvement of the basal limbic\\u000a system in primary and secondary mood disorders. This study tested the hypothesis of brainstem midline abnormality in depression\\u000a and investigated 31 PD patients by magnetic resonance
Daniela Berg; Tillmann Supprian; Erich Hofmann; Bj�rn Zeiler; Andreas J�ger; Klaus W. Lange; Karlheinz Reiners; Thomas Becker; Georg Becker
The Role of the Cerebellum in Subsecond Time Perception: Evidence from Repetitive Transcranial Magnetic Stimulation
In three experiments, we investigated the role of the cerebellum in sub- and suprasecond time perception by using repetitive transcranial magnetic stimulation (rTMS). In Experiment 1, subjects underwent four 8-min 1-Hz rTMS sessions in a within-subject design. rTMS sites were the medial cerebellum (real and sham rTMS), left lateral cerebellum, and right lateral cerebellum. Following each rTMS session, subjects completed
Kwang-hyuk Lee; Paul N. Egleston; Wendy H. Brown; Abigail N. Gregory; Anthony T. Barker; Peter W. R. Woodruff
Effects of low-frequency transcranial magnetic stimulation on motor excitability and basic motor behavior
Objective: To explore effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) on motor excitability and basic motor behavior in humans.Design and Methods: Seven normal volunteers underwent 1 Hz rTMS of the hand representation of the right M1 for 15 min at an intensity of 115% of the individual resting motor threshold. The effects of
Wolf Muellbacher; Ulf Ziemann; Babak Boroojerdi; Mark Hallett
Cognitive effects of high-frequency repetitive transcranial magnetic stimulation: a systematic review
Transcranial magnetic stimulation (TMS) was introduced as a non-invasive tool for the investigation of the motor cortex. The\\u000a repetitive application (rTMS), causing longer lasting effects, was used to study the influence on a variety of cerebral functions.\\u000a High-frequency (>1�Hz) rTMS is known to depolarize neurons under the stimulating coil and to indirectly affect areas being\\u000a connected and related to emotion
Birgit Guse; Peter Falkai; Thomas Wobrock
Transcranial magnetic stimulation reveals the content of visual short-term memory in the visual cortex
Cortical areas involved in sensory analysis are also believed to be involved in short-term storage of that sensory information. Here we investigated whether transcranial magnetic stimulation (TMS) can reveal the content of visual short-term memory (VSTM) by bringing this information to visual awareness. Subjects were presented with two random-dot displays (moving either to the left or to the right) and
Juha Silvanto; Zaira Cattaneo
Assessing the neural correlates of self-enhancement bias: a transcranial magnetic stimulation study
Considerable research has focused on overly positive self-perceptions (self-enhancement), and yet little is known about the\\u000a underlying neural mechanisms. The present study sought to assess the neural correlates of self-enhancement by applying Transcranial\\u000a Magnetic Stimulation (TMS) to three brain regions. Twelve participants rated their best friend, as well as the self on a set\\u000a of desirable or undesirable traits while
Virginia S. Y. Kwan; Veronica Barrios; Giorgio Ganis; Jamie Gorman; Claudia Lange; Monisha Kumar; Alejandro Shepard; Julian Paul Keenan
Effect of repetitive transcranial magnetic stimulation on rate of memory acquisition
Repetitive transcranial magnetic stimulation (rTMS) may temporarily accelerate knowledge acquisition by neural networks, possibly by promoting rapid Hebbian learning. The authors tested this hypothesis in 20 normal subjects by comparing the impact of 25 minutes of high-frequency left dorsolateral prefrontal rTMS with that of sham rTMS on subsequent knowledge acquisition in several procedural and declarative memory domains. No significant group
Heidi L. Roth; Stephen E. Nadeau; William J. Triggs
The role of transcranial magnetic stimulation in the study of cerebellar cognitive function
Transcranial magnetic stimulation (TMS) allows non-invasive stimulation of brain structures. This technique can be used either\\u000a for stimulating the motor cortex, recording motor evoked potentials from peripheral muscles, or for modulating the excitability\\u000a of other non-motor areas in order to establish their necessity for a given task. TMS of the cerebellum can give interesting\\u000a insights on the cerebellar functions. Paired-TMS
Massimiliano Oliveri; Sara Torriero; Giacomo Koch; Silvia Salerno; Laura Petrosini; Carlo Caltagirone
Neural Correlates of the Contextual Interference Effect in Motor Learning: A Transcranial Magnetic Stimulation Investigation
The authors applied transcranial magnetic stimulation (TMS) to investigate the causal role of the primary motor cortex (M1) for the contextual-interference effect in motor learning. Previous work using a nonfocal TMS coil suggested a casual role for M1 during high-interference practice conditions, but this hypothesis has not yet been proven. In the 1st experiment, participants practiced 3 rapid elbow flexion�extension
Chien-Ho Lin; Carolee J. Winstein; Beth E. Fisher; Allan D. Wu
Cholinergic dysfunction and amnesia in patients with Wernicke�Korsakoff syndrome: a transcranial magnetic stimulation study
The specific neurochemical substrate underlying the amnesia in patients with Wernicke�Korsakoff syndrome (WKS) is still poorly\\u000a defined. Memory impairment has been linked to dysfunction of neurons in the cholinergic system. A transcranial magnetic stimulation\\u000a (TMS) protocol, the short latency afferent inhibition (SAI), may give direct information about the function of some cholinergic\\u000a pathways in the human motor cortex. In the
Raffaele NardoneJurgen; J�rgen Bergmann; Pierpaolo De Blasi; Martin Kronbichler; J�rg Kraus; Francesca Caleri; Frediano Tezzon; Gunther Ladurner; Stefan Golaszewski
Hemispheric asymmetry in cortical control of memory-guided saccades. A transcranial magnetic stimulation study
To study the temporal organisation of memory-guided saccade control we used single-pulse transcranial magnetic stimulation (TMS) over the left posterior parietal (PPC) and prefrontal cortex (PFC) in eight healthy subjects. TMS was applied either following presentation of a visual target, i.e. 160, 260, and 360 ms after the flashed point, or during the period of memorisation, i.e. between 700 and
Ren� M. M�ri; Bertrand Gaymard; Sophie Rivaud; Anne-Isabelle Vermersch; Christian W. Hess; Charles Pierrot-Deseilligny
Subthreshold low frequency repetitive transcranial magnetic stimulation selectively decreases facilitation in the motor cortex
Objective: To investigate the modulatory effect of a subthreshold low frequency repetitive transcranial magnetic stimulation (rTMS) train on motor cortex excitability.Methods: The study consisted of two separate experiments. Subjects received a 10min long subthreshold 1Hz rTMS train. In the first experiment, (single pulse paradigm), cortical excitability was assessed by measuring the amplitude of motor evoked potentials (MEPs) before and after
Jose Rafael Romero; David Anschel; Roland Sparing; Massimo Gangitano; Alvaro Pascual-Leone
Repetitive transcranial magnetic stimulation increases the release of dopamine in the mesolimbic and mesostriatal system
Repetitive transcranial magnetic stimulation (rTMS) is suggested to be a potentially useful treatment in major depression. In order to optimize rTMS for therapeutic use, it is necessary to understand the neurobiological mechanisms involved, particularly the nature of the neurochemical changes induced. Using intracerebral microdialysis in urethane-anesthetized and conscious adult male Wistar rats, we monitored the effects of acute rTMS (20
M. E Keck; T Welt; M. B M�ller; A Erhardt; F Ohl; N Toschi; F Holsboer; I Sillaber
Lasting influence of repetitive transcranial magnetic stimulation on intracortical excitability in human subjects
We studied the effects of a train of 30 pulses of repetitive transcranial magnetic stimulation (rTMS) at frequencies of 5 and 15 Hz and at an intensity of 120% of resting motor threshold on human motor cortex excitability. Intracortical inhibition (ICI) and intracortical facilitation (ICF) after rTMS were tested by a conditioning-test designed paired-pulse paradigm. After 15 Hz rTMS, ICI
Tao Wu; Martin Sommer; Frithjof Tergau; Walter Paulus
Transcranial Magnetic Stimulation of Left Temporoparietal Cortex and Medication-Resistant Auditory Hallucinations
Background: Neuroimaging studies suggest that audi- tory hallucinations (AHs) of speech arise, at least in part, from activation of brain areas underlying speech percep- tion. One-hertz repetitive transcranial magnetic stimu- lation (rTMS) produces sustained reductions in cortical activation. Recent results of 4-day administration of 1-Hz rTMS to left temporoparietal cortex were superior to those of sham stimulation in reducing AHs.
Ralph E. Hoffman; Keith A. Hawkins; Ralitza Gueorguieva; Nash N. Boutros; Fady Rachid; Kathleen Carroll; John H. Krystal
A randomized clinical trial of repetitive transcranial magnetic stimulation in the treatment of major depression
Background: Multiple groups have reported on the use of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant major depression. The purpose of this study is to assess the efficacy of rTMS in unmedicated, treatment-resistant patients who meet criteria for major depression.Methods: Depressed subjects, who had failed to respond to a median of four treatment trials, were assigned in a randomized double-blind
Robert M. Berman; Meera Narasimhan; Gerard Sanacora; Alexander P. Miano; Ralph E. Hoffman; X. Sylvia Hu; Dennis S. Charney; Nashaat N. Boutros
Effects of repetitive transcranial magnetic stimulation on visual evoked potentials in migraine
Summary Between attacks, migraine patients are characterized by potentiation instead of habituation of stimulation- evoked cortical responses. It is debated whether this is due to increased or decreased cortical excitability. We have studied the changes in visual cortex excitabil- ity by recording pattern-reversal visual evoked potentials (PR-VEP) after low- and high-frequency repetitive transcranial magnetic stimulation (rTMS), known respectively for their
V. Bohotin; A. Fumal; M Vandenheede; P. Gerard; C. Bohotin; A. Maertens de Noordhout; J. Schoenen
Long-lasting depression of motor-evoked potentials to transcranial magnetic stimulation following exercise
We used transcranial magnetic stimulation to study the modulation of motor cortex excitability after rapid repetitive movements. Eleven healthy subjects aged 24�32 years were evaluated. Serial motor-evoked potential (MEP) recordings were performed from the right thenar eminence every 5 min for a period of 20 min at rest and for a period of 35 min after repetitive abduction-adduction of the
Giampietro Zanette; Claudio Bonato; Alberto Polo; Michele Tinazzi; Paolo Manganotti; Antonio Fiaschi
Long-term maintenance of the analgesic effects of transcranial magnetic stimulation in fibromyalgia
We assessed for the first time the long-term maintenance of repetitive transcranial magnetic stimulation (rTMS)-induced analgesia in patients with chronic widespread pain due to fibromyalgia. Forty consecutive patients were randomly assigned, in a double-blind fashion, to 2 groups: one receiving active rTMS (n=20) and the other, sham stimulation (n=20), applied to the left primary motor cortex. The stimulation protocol consisted
Alaa Mhalla; Sophie Baudic; Daniel Ciampi de Andrade; Michele Gautron; Serge Perrot; Manoel Jacobson Teixeira; Nadine Attal; Didier Bouhassira
Introducing navigated transcranial magnetic stimulation as a refined brain mapping methodology
.�� A major intrinsic limitation of transcranial magnetic stimulation (TMS) to map the human brain lies in the unclear relationship\\u000a between the position of the stimulating coil on the scalp and the underlying stimulated cortex. The relationship between structure\\u000a and function as the major feature constituting a brain mapping modality can therefore not be established. Recent advances\\u000a in image processing
Timo Krings; Keith H. Chiappa; Henrik Foltys; Marcus H. T. Reinges; Rees G. Cosgrove; Armin Thron
Contribution of transcranial magnetic stimulation to the understanding of cortical mechanisms involved in motor control
Transcranial magnetic stimulation (TMS) was initially used to evaluate the integrity of the corticospinal tract in humans non-invasively. Since these early studies, the development of paired-pulse and repetitive TMS protocols allowed investigators to explore inhibitory and excitatory interactions of various motor and non-motor cortical regions within and across cerebral hemispheres. These applications have provided insight into the intracortical physiological processes
Janine Reis; Orlando B. Swayne; Yves Vandermeeren; Mickael Camus; Michael A. Dimyan; Michelle Harris-Love; Monica A. Perez; John C. Rothwell; Leonardo G. Cohen
Long Lasting Modulation of Cortical Oscillations after Continuous Theta Burst Transcranial Magnetic Stimulation
Transcranial magnetic theta burst stimulation (TBS) differs from other high-frequency rTMS protocols because it induces plastic changes up to an hour despite lower stimulus intensity and shorter duration of stimulation. However, the effects of TBS on neuronal oscillations remain unclear. In this study, we used electroencephalography (EEG) to investigate changes of neuronal oscillations after continuous TBS (cTBS), the protocol that
Nor Azila Noh; Giorgio Fuggetta; Paolo Manganotti; Antonio Fiaschi
Role of the Left DLPFC in Endogenous Task Preparation: Experimental Repetitive Transcranial Magnetic Stimulation Study
The precise role of the dorsolateral prefrontal cortex (DLPFC) in attentional set activation is still not entirely clear. Hence, repetitive transcranial magnetic stimulation (rTMS) can be applied to interfere with neural processing to determine whether a specific brain area is required in task performance. In this study, the influence of one session of high-frequency (HF)-rTMS of the left DLPFC on
Marie-Anne Vanderhasselt; Rudi De Raedt; Lemke Leyman; Chris Baeken
Safety of theta burst transcranial magnetic stimulation: a systematic review of the literature.
Theta burst stimulation (TBS) protocols have recently emerged as a method to transiently alter cortical excitability in the human brain through repetitive transcranial magnetic stimulation. TBS involves applying short trains of stimuli at high frequency repeated at intervals of 200 milliseconds. Because repetitive transcranial magnetic stimulation is known to carry a risk of seizures, safety guidelines have been established. TBS has the theoretical potential of conferring an even higher risk of seizure than other repetitive transcranial magnetic stimulation protocols because it delivers high-frequency bursts. In light of the recent report of a seizure induced by TBS, the safety of this new protocol deserves consideration. We performed an English language literature search and reviewed all studies published from May 2004 to December 2009 in which TBS was applied. The adverse events were documented, and crude risk was calculated. The majority of adverse events attributed to TBS were mild and occurred in 5% of subjects. Based on this review, TBS seems to be a safe and efficacious technique. However, given its novelty, it should be applied with caution. Additionally, this review highlights the need for rigorous documentation of adverse events associated with TBS and intensity dosing studies to assess the seizure risk associated with various stimulation parameters (e.g., frequency, intensity, and location). PMID:21221011
Oberman, Lindsay; Edwards, Dylan; Eldaief, Mark; Pascual-Leone, Alvaro
Calculating the electric field in real human head by transcranial magnetic stimulation with shield plate
In this paper, we present a transcranial magnetic stimulation (TMS) system by incorporating a conductive shield plate. The magnetic field, induced current density, and electric field in a real human head were calculated by impedance method and the results were compared with TMS without shielding. Our results show that the field localization can be improved by introducing a conductive shield plate; the stimulation magnitude (depth) in the brain is reduced comparing with the TMS without shielding. The strong magnetic field near the TMS coil is difficult to be efficiently shielded by a thinner conductive shield plate.
Probing the Pathophysiology of Auditory\\/Verbal Hallucinations by Combining Functional Magnetic Resonance Imaging and Transcranial Magnetic Stimulation
Functional magnetic resonance imaging and repetitive transcranial magnetic stimulation (rTMS) were used to explore the pathophys- iology of auditory\\/verbal hallucinations (AVHs). Sixteen patients with schizophrenia-spectrum disorder were studied with continuous or near continuous AVHs. For patients with intermittent hallucina- tions (N 5 8), blood oxygenation level--dependent (BOLD) activation maps comparing hallucination and nonhallucination periods were gen- erated. For patients with
Ralph E. Hoffman; Michelle Hampson; Kun Wu; Adam W. Anderson; John C. Gore; Robert J. Buchanan; R. Todd Constable; Keith A. Hawkins; Neayka Sahay; J. H. Krystal
Fundamentals of Transcranial Electric and Magnetic Stimulation Dose: Definition, Selection, and Reporting Practices
The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose of EM stimulation and how it should be reported. The biological effects of EM stimulation are mediated through an electromagnetic field injected (via electric stimulation) or induced (via magnetic stimulation) in the body. Therefore, transcranial EM stimulation dose ought to be defined by all parameters of the stimulation device that affect the electromagnetic field generated in the body, including the stimulation electrode or coil configuration parameters: shape, size, position, and electrical properties, as well as the electrode or coil current (or voltage) waveform parameters: pulse shape, amplitude, width, polarity, and repetition frequency; duration of and interval between bursts or trains of pulses; total number of pulses; and interval between stimulation sessions and total number of sessions. Knowledge of the electromagnetic field generated in the body may not be sufficient but is necessary to understand the biological effects of EM stimulation. We believe that reporting of EM stimulation dose should be guided by the principle of reproducibility: sufficient information about the stimulation parameters should be provided so that the dose can be replicated. This paper provides fundamental definition and principles for reporting of dose that encompass any transcranial EM brain stimulation protocol.
Peterchev, Angel V.; Wagner, Timothy A.; Miranda, Pedro C.; Nitsche, Michael A.; Paulus, Walter; Lisanby, Sarah H.; Pascual-Leone, Alvaro; Bikson, Marom
Instrumentation for the measurement of electric brain responses to transcranial magnetic stimulation
There is described a 60-channel EEG acquisition system designed for the recording of scalp-potential distributions starting\\u000a just 2.5ms after individual transcranial magnetic stimulation (TMS) pulses. The amplifier comprises gain-control and sample-and-hold\\u000a circuits to prevent large artefacts from magnetically induced voltages in the leads. The maximum amplitude of the stimulus\\u000a artefact during the 2.5ms gating period is 1.7 ?V, and 5
J. Virtanen; J. Ruohonen; R. N��t�nen; R. J. Ilmoniemi
Cerebellar transcranial magnetic stimulation impairs verbal working memory
Previous functional magnetic resonance imaging and patient studies indicate cerebellar participation in verbal working memory. In particular, event-related functional magnetic resonance imaging showed superior cerebellar activation during the initial encoding phase of the Sternberg task. This study used functional magnetic resonance imaging-guided trans- cranial magnetic stimulation (TMS) to test whether disruption of the right superior cerebellum (hemispheric lobule VI\\/Crus I)
John E. Desmond; S. H. Annabel Chen; Perry B. Shieh
Non-invasive Transcranial Magnetic Stimulation (TMS) of the Motor Cortex for Neuropathic Pain-At the Tipping Point?
The term "neuropathic pain" (NP) refers to chronic pain caused by illnesses or injuries that damage peripheral or central pain-sensing neural pathways to cause them to fire inappropriately and signal pain without cause. Neuropathic pain is common, complicating diabetes, shingles, HIV, and cancer. Medications are often ineffective or cause various adverse effects, so better approaches are needed. Half a century ago, electrical stimulation of specific brain regions (neuromodulation) was demonstrated to relieve refractory NP without distant effects, but the need for surgical electrode implantation limited use of deep brain stimulation. Next, electrodes applied to the dura outside the brain's surface to stimulate the motor cortex were shown to relieve NP less invasively. Now, electromagnetic induction permits cortical neurons to be stimulated entirely non-invasively using transcranial magnetic stimulation (TMS). Repeated sessions of many TMS pulses (rTMS) can trigger neuronal plasticity to produce long-lasting therapeutic benefit. Repeated TMS already has US and European regulatory approval for treating refractory depression, and multiple small studies report efficacy for neuropathic pain. Recent improvements include "frameless stereotactic" neuronavigation systems, in which patients' head MRIs allow TMS to be applied to precise underlying cortical targets, minimizing variability between sessions and patients, which may enhance efficacy. Transcranial magnetic stimulation appears poised for the larger trials necessary for regulatory approval of a NP indication. Since few clinicians are familiar with TMS, we review its theoretical basis and historical development, summarize the neuropathic pain trial results, and identify issues to resolve before large-scale clinical trials. PMID:24228166
Treister, Roi; Lang, Magdalena; Klein, Max M; Oaklander, Anne Louise
Non-invasive Transcranial Magnetic Stimulation (TMS) of the Motor Cortex for Neuropathic Pain--At the Tipping Point?
The term �neuropathic pain� (NP) refers to chronic pain caused by illnesses or injuries that damage peripheral or central pain-sensing neural pathways to cause them to fire inappropriately and signal pain without cause. Neuropathic pain is common, complicating diabetes, shingles, HIV, and cancer. Medications are often ineffective or cause various adverse effects, so better approaches are needed. Half a century ago, electrical stimulation of specific brain regions (neuromodulation) was demonstrated to relieve refractory NP without distant effects, but the need for surgical electrode implantation limited use of deep brain stimulation. Next, electrodes applied to the dura outside the brain�s surface to stimulate the motor cortex were shown to relieve NP less invasively. Now, electromagnetic induction permits cortical neurons to be stimulated entirely non-invasively using transcranial magnetic stimulation (TMS). Repeated sessions of many TMS pulses (rTMS) can trigger neuronal plasticity to produce long-lasting therapeutic benefit. Repeated TMS already has US and European regulatory approval for treating refractory depression, and multiple small studies report efficacy for neuropathic pain. Recent improvements include �frameless stereotactic� neuronavigation systems, in which patients� head MRIs allow TMS to be applied to precise underlying cortical targets, minimizing variability between sessions and patients, which may enhance efficacy. Transcranial magnetic stimulation appears poised for the larger trials necessary for regulatory approval of a NP indication. Since few clinicians are familiar with TMS, we review its theoretical basis and historical development, summarize the neuropathic pain trial results, and identify issues to resolve before large-scale clinical trials.
Treister, Roi; Lang, Magdalena; Klein, Max M.; Oaklander, Anne Louise
Pulse configuration-dependent effects of repetitive transcranial magnetic stimulation on visual perception.
Transcranial magnetic stimulation (TMS) is a noninvasive technique for direct stimulation of the neocortex. In the last two decades it is successfully applied in the study of motor and sensory physiology. TMS uses the indirect induction of electrical fields in the brain generated by intense changes of magnetic fields applied to the scalp. It encompasses two widely used waveform configurations: mono-phasic magnetic pulses induce a single current in the brain while biphasic pulses induce at least two currents of inverse direction. As has been shown for the motor cortex, efficacy of repetitive transcranial magnetic stimulation (rTMS) may depend on pulse configuration. In order to clarify this question with regard to visual perception, static contrast sensitivities (sCS) were evaluated before, during, immediately after and 10 minutes after monophasic and biphasic low frequency (1 Hz) rTMS applied to the occipital cortex of 15 healthy subjects. The intensity of stimulation was the phosphene threshold of each individual subject. Using 4 c/d spatial frequency, significant sCS loss was found during and immediately after 10 min of monophasic stimulation, while biphasic stimulation resulted in no significant effect. Ten minutes after the end of stimulation, the sCS values were at baseline level again. However, reversed current flow direction resulted in an increased efficacy of biphasic and decreased efficacy of monophasic stimulation. Our results are in agreement with previous findings showing that primary visual functions, such as contrast detection, can be transiently altered by low frequency transcranial magnetic stimulation. However the effect of modulation significantly depends on the current waveform and direction. PMID:12488802
Antal, Andrea; Kincses, Tamas Z; Nitsche, Michael A; Bartfai, Orsolya; Demmer, Iris; Sommer, Martin; Paulus, Walter
Efficiency test of filtering methods for the removal of transcranial magnetic stimulation artifacts on human electroencephalography with artificially transcranial magnetic stimulation-corrupted signals
A new approach is proposed to test the efficiency of methods, such as the Kalman filter and the independent component analysis (ICA), when applied to remove the artifacts induced by transcranial magnetic stimulation (TMS) from electroencephalography (EEG). By using EEG recordings corrupted by TMS induction, the shape of the artifacts is approximately described with a model based on an equivalent circuit simulation. These modeled artifacts are subsequently added to other EEG signals-this time not influenced by TMS. The resulting signals prove of interest since we also know their form without the pseudo-TMS artifacts. Therefore, they enable us to use a fit test to compare the signals we obtain after removing the artifacts with the original signals. This efficiency test turned out very useful in comparing the methods between them, as well as in determining the parameters of the filtering that give satisfactory results with the automatic ICA.
Zilber, Nicolas A.; Katayama, Yoshinori; Iramina, Keiji; Erich, Wintermantel
Impairment of visual perception and visual short term memory scanning by transcranial magnetic stimulation of occipital cortex
Transcranial magnetic stimulation (TMS) of occipital cortex was performed using a magneto-electric stimulator with a maximum output of 2 Tesla in 24 normal volunteers. The identification of trigrams, presented for 14 ms in horizontal or vertical arrays was significantly impaired when the visual stimulus preceded the occipital magnetic shock by 40 to 120 ms. The extent of impairment was related
G. Beckers; V. H�mberg
The effect of transcranial magnetic stimulation on the soleus H reflex during human walking
The effect of transcranial magnetic stimulation (TMS) on the soleus H reflex was investigated in the stance phase of walking in seventeen human subjects. For comparison, measurements were also made during quiet standing, matched tonic plantar flexion and matched dynamic plantar flexion.During walking and dynamic plantar flexion subliminal (0.95 times threshold for a motor response in the soleus muscle) TMS evoked a large short-latency facilitation (onset at conditioning-test interval: ?5 to ?1 ms) of the H reflex followed by a later (onset at conditioning-test interval: 3�16 ms) long-lasting inhibition. In contrast, during standing and tonic plantar flexion the short-latency facilitation was either absent or small and the late inhibition was replaced by a long-lasting facilitation.When grading the intensity of TMS it was found that the short-latency facilitation had a lower threshold during walking than during standing and tonic plantar flexion. Regardless of the stimulus intensity the late facilitation was never seen during walking and dynamic plantar flexion and the late inhibition was not seen, except for one subject, during standing and tonic plantar flexion.A similar difference in the threshold of the short-latency facilitation between walking and standing was not observed when the magnetic stimulation was replaced by transcranial electrical stimulation.The lower threshold of the short-latency facilitation evoked by magnetic but not electrical transcranial stimulation during walking compared with standing suggests that cortical cells with direct motoneuronal connections increase their excitability in relation to human walking. The significance of the differences in the late facilitatory and inhibitory effects during the different tasks is unclear.
Petersen, Nicolas; Christensen, Lars O D; Nielsen, Jens
Combined use of transcranial magnetic stimulation and metal electrode implants: a theoretical assessment of safety considerations.
This paper provides a theoretical assessment of the safety considerations encountered in the simultaneous use of transcranial magnetic stimulation (TMS) and neurological interventions involving implanted metallic electrodes, such as electrocorticography. Metal implants are subject to magnetic forces due to fast alternating magnetic fields produced by the TMS coil. The question of whether the mechanical movement of the implants leads to irreversible damage of brain tissue is addressed by an electromagnetic simulation which quantifies the magnitude of imposed magnetic forces. The assessment is followed by a careful mechanical analysis determining the maximum tolerable force which does not cause irreversible tissue damage. Results of this investigation provide useful information on the range of TMS stimulator output powers which can be safely used in patients having metallic implants. It is shown that conventional TMS applications can be considered safe when applied on patients with typical electrode implants as the induced stress in the brain tissue remains well below the limit of tissue damage. PMID:23135209
Golestanirad, Laleh; Rouhani, Hossein; Elahi, Behzad; Shahim, Kamal; Chen, Robert; Mosig, Juan R; Pollo, Claudio; Graham, Simon J
Two phases of intracortical inhibition revealed by transcranial magnetic threshold tracking
Intracortical inhibition was investigated in normal human volunteers by paired-pulse transcranial magnetic stimulation, using\\u000a a new, computer-assisted threshold-tracking method. Motor threshold was defined as the stimulus amplitude required to evoke\\u000a a motor evoked potential of 0.2�mV (peak-to-peak) in abductor pollicis brevis, and inhibition was measured as the percentage\\u000a increase in threshold, when the test stimulus was preceded by a subthreshold
R. J. Fisher; Y. Nakamura; S. Bestmann; J. C. Rothwell; H. Bostock
Detailed 3D models of the induced electric field of transcranial magnetic stimulation coils
Previous models neglected contributions from current elements spanning the full geometric extent of wires in transcranial magnetic stimulation (TMS) coils. A detailed account of TMS coil wiring geometry is shown to provide significant improvements in the accuracy of electric field (E-field) models. Modeling E-field dependence based on the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed E-field models were accurate up to the surface of the coil body (within 0.5% of measured) where simple models were often inadequate (up to 32% different from measured).
Salinas, F. S.; Lancaster, J. L.; Fox, P. T.
Cortical inhibition, excitation, and connectivity in schizophrenia: a review of insights from transcranial magnetic stimulation.
Schizophrenia (SCZ) is a debilitating mental illness with an elusive pathophysiology. Over the last decade, theories emphasizing cortical dysfunction have received increasing attention to explain the heterogeneous symptoms experienced in SCZ. Transcranial magnetic stimulation (TMS) is a noninvasive form of brain stimulation that is particularly suited to probing the fidelity of specific excitatory and inhibitory neuronal populations in conscious humans. In this study, we review the contribution of TMS in assessing inhibitory and excitatory neuronal populations and their long-range connections in SCZ. In addition, we discuss insights from combined TMS and electroencephalography into the functional consequences of impaired excitation/inhibition on cortical oscillations in SCZ. PMID:23722199
Rogasch, Nigel C; Daskalakis, Zafiris J; Fitzgerald, Paul B
Effect of repetitive transcranial magnetic stimulation on rectal function and emotion in humans
Background��A previous brain imaging study demonstrated activation of the right dorsolateral prefrontal cortex (DLPFC) during visceral\\u000a nociception, and this activation was associated with anxiety. We hypothesized that functional modulation of the right DLPFC\\u000a by repetitive transcranial magnetic stimulation (rTMS) can reveal the actual role of right DLPFC in brain�gut interactions\\u000a in humans.\\u000a \\u000a \\u000a \\u000a \\u000a Methods��Subjects were 11 healthy males aged 23.5���1.4 (mean���SE)
Yuuichi AizawaJoe; Joe Morishita; Michiko Kano; Takayuki Mori; Shin-Ichi Izumi; Kenichiro Tsutsui; Toshio Iijima; Motoyori Kanazawa; Shin Fukudo
Transcranial Magnetic Stimulation for the treatment of tinnitus: Effects on cortical excitability
Background Low frequency repetitive transcranial magnetic stimulation (rTMS) has been proposed as an innovative treatment for chronic tinnitus. The aim of the present study was to elucidate the underlying mechanism and to evaluate the relationship between clinical outcome and changes in cortical excitability. We investigated ten patients with chronic tinnitus who participated in a sham-controlled crossover treatment trial. Magnetic-resonance-imaging and positron-emission-tomography guided 1 Hz rTMS were performed over the auditory cortex on 5 consecutive days. Active and sham treatments were separated by one week. Parameters of cortical excitability (motor thresholds, intracortical inhibition, intracortical facilitation, cortical silent period) were measured serially before and after rTMS treatment by using single- and paired-pulse transcranial magnetic stimulation. Clinical improvement was assessed with a standardized tinnitus-questionnaire. Results We noted a significant interaction between treatment response and changes in motor cortex excitability during active rTMS. Specifically, clinical improvement was associated with an increase in intracortical inhibition, intracortical facilitation and a prolongation of the cortical silent period. These results indicate that intraindividual changes in cortical excitability may serve as a correlate of response to rTMS treatment. Conclusion The observed alterations of cortical excitability suggest that low frequency rTMS may evoke long-term-depression like effects resulting in an improvement of subcortical inhibitory function.
Langguth, Berthold; Kleinjung, Tobias; Marienhagen, Joerg; Binder, Harald; Sand, Philipp G; Hajak, Goran; Eichhammer, Peter
Evaluation of proximal facial nerve conduction by transcranial magnetic stimulation
A magnetic stimulator was used for direct transcutaneous stimulation of the intracranial portion of the facial nerve in 15 normal subjects and in patients with Bell's palsy, demyelinating neuropathy, traumatic facial palsy and pontine glioma. Compound muscle action potentials (CMAPs) thus elicited in the orbicularis oris muscle of controls were of similar amplitude but longer latency (1.3 SD 0.15 ms)
T N Schriefer; K R Mills; N M Murray; C W Hess
Epileptic seizures triggered directly by focal transcranial magnetic stimulation
Focal, secondarily generalizing epileptic seizures were released by magnetic stimulation in a patient with focal epilepsy. The stimulation induced seizures had a similar clinical appearance to the patient's spontaneous seizures. They were released exclusively by an angulated �figure-of-8� coil which stimulates the brain more focally as compared to the commonly used flat round coil. The epileptic focus could be located
J. Classen; O. W. Witte; G. Schlaug; R. J. Seitz; H. Holthausen; R. Benecke
[Present and future of the transcranial magnetic stimulation].
Magnetic stimulation has called the attention of neuroscientists and the public due to the possibility to stimulate and "control" the nervous system in a non-invasive way. It has helped to make more accurate diagnosis, and apply more effective treatments and rehabilitation protocols in several diseases that affect the nervous system. Likewise, this novel tool has increased our knowledge about complex neural behavior, its connections as well as its plastic modulation. Magnetic stimulation applied in simple or paired-pulse protocols is a useful alternative in the diagnosis of diseases such as multiple sclerosis, Parkinson disease, epilepsy, dystonia, amyotrophic lateral sclerosis, cerebrovascular disease, and sleep disorders. From the therapeutic perspective, magnetic stimulation applied repetitively has been found useful, with different degrees of efficacy, in treating resistant depression, tinnitus, psychogenic dysphonia, Alzheimer disease, autism, Parkinson disease, dystonia, stroke, epilepsy, generalized anxiety as well as post traumatic stress disorder, auditory hallucinations, chronic pain, aphasias, obsessive-compulsive disorders, L-dopa induced dyskynesia, mania and Rasmussen syndrome, among others. The potential of magnetic stimulation in neurorehabilitation is outstanding, with excellent range of safety and, in practical terms, without side effects. PMID:23781715
Leon-Sarmiento, Fidias E; Granadillo, El�as; Bayona, Edgardo A
Assessing Low-frequency Repetitive Transcranial Magnetic Stimulation with Functional Magnetic Resonance Imaging: A Case Series.
Background and Purpose. This case series assesses the effects of five consecutive days of low-frequency (1?Hz) repetitive transcranial magnetic stimulation (rTMS) with and without a 6-Hz primer. Although this paper studies able-bodied individuals, similar rTMS protocols are used to facilitate motor recovery in patients with hemiplegia following stroke. However, the cortical mechanisms associated with repeated daily doses of rTMS are not completely understood. Case Description. Four right-handed healthy volunteers (two men, aged 20-50?years) participated in a double-blind case series of primed and unprimed rTMS. Functional magnetic resonance imaging was used to compare task-related haemodynamics during a simple motor task and resting-state cortical connectivity. Understanding the mechanisms of repeated rTMS sessions may serve as a precursor to development of rTMS paradigms involving motor cortex stimulation in patients with a range of neurologic dysfunction. Outcomes. Following five consecutive days of rTMS, all subjects had reduced task-related haemodynamics. Resting-state brain connectivity between motor regions was reduced only after primed rTMS. Discussion. This is the first study to indicate that resting-state brain connectivity can distinguish the effect of primed and unprimed rTMS to a greater extent than task-related haemodynamics. Furthermore, priming may inhibit the connectivity between the area of the cortex underlying the rTMS site and remote brain regions. Significance. These findings benefit rTMS rehabilitation studies by examining haemodynamics on repeated days of stimulation and incorporating resting-state brain connectivity analysis to further understand underlying neural mechanisms. Furthermore, this work encourages the utilization of resting connectivity in future rTMS studies. Copyright � 2011 John Wiley & Sons, Ltd. PMID:21766399
Glielmi, Christopher B; Butler, Andrew J; Niyazov, Dmitriy M; Darling, Warren G; Epstein, Charles M; Alberts, Jay L; Hu, Xiaoping P
Noninvasive brain stimulation with transcranial magnetic or direct current stimulation (TMS\\/tDCS)�From insights into human memory to therapy of its dysfunction
Noninvasive stimulation of the brain by means of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) has driven important discoveries in the field of human memory functions. Stand-alone or in combination with other brain mapping techniques noninvasive brain stimulation can assess issues such as location and timing of brain activity, connectivity and plasticity of neural circuits and functional
Roland Sparing; Felix M. Mottaghy
Modulation of N400 in Chronic Non-Fluent Aphasia Using Low Frequency Repetitive Transcranial Magnetic Stimulation (rTMS)
ERIC Educational Resources Information Center
Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43 months post stimulation. The present study aimed to investigate the electrophysiological correlates�
Barwood, Caroline H. S.; Murdoch, Bruce E.; Whelan, Brooke-Mai; Lloyd, David; Riek, Stephan; O'Sullivan, John D.; Coulthard, Alan; Wong, Andrew
Verbal working memory components can be selectively influenced by transcranial magnetic stimulation in patients with left temporal lobe epilepsy
The aim of this study was to investigate whether transcranial magnetic stimulation (TMS) can be used for a lateralization of verbal and non-verbal memory functions in candidates for epilepsy surgery by inducing focal, material-specific memory deficits. Twenty patients who underwent presurgical epilepsy evaluation with chronically implanted subdural strip electrodes were submitted to focal TMS over the temporal lobes and the
Emrah D�zel; Andreas Hufnagel; Christoph Helmstaedter; Christian Elger
Transcranial Magnetic Stimulation Effects on One-Trial Learning and Response to Anxiogenic Stimuli in Adult Male Rats
Transcranial magnetic stimulation (TMS) is a relatively new technique for inducing small, localized, and reversible changes in living brain tissue and has been suggested to have antidepressant properties in humans and animal models of depression. Memory function generally has been found to be unaffected by TMS, although some studies have raised the possibility of memory interference from TMS. Additionally, there
Dawson W. Hedges; Brian J. Higginbotham; David L. Salyer; Trent D. Lund
Effects of transcranial magnetic stimulation over the region of the supplementary motor area during sequences of memory-guided saccades
Transcranial magnetic stimulation (TMS) over the region of the supplementary motor area (SMA) was used to study the cortical control of sequences of memory-guided saccades. In ten healthy subjects, TMS was applied during (a) the target presentation (learning) phase, (b) the memorization phase, and (c) the execution phase of such saccade sequences. Stimulation during the presentation phase resulted in a
R. M. M�ri; S. Rivaud; A. I. Vermersch; J. M. L�ger; C. Pierrot-Deseilligny
Impairment of cortical inhibition in writer's cramp as revealed by changes in electromyographic silent period after transcranial magnetic stimulation
Changes in silent period (SP) duration following transcranial magnetic stimulation (TMS) set at 20% above the motor threshold were studied in six subjects suffering from writer's cramp, while performing dystonic movement and during voluntary isometric contraction of the muscles mostly involved in the dystonic movement. Dependency of SP duration on the intensity of preceding muscle contraction was compared on both
S. R Filipovi?; M Ljubisavljevi?; M Svetel; S Milanovi?; A Ka?ar; V. S Kosti?
The effect of current direction induced by transcranial magnetic stimulation on the corticospinal excitability in human brain
Evoked spinal cord potentials (ESCPs) from the cervical epidural space and motor evoked potentials (MEPs) from the hand muscles were recorded simultaneously in 6 subjects following transcranial magnetic stimulation in two different coil orientations on motor cortex. The onset latency of the MEPs was approximately 1 ms shorter when the induced current flowed in a latero-medial direction (L-M stimulation) on
Kazuo Kaneko; Shinya Kawai; Yasunori Fuchigami; Hideki Morita; Akira Ofuji
Enhancement of human motor cortex inhibition by the dopamine receptor agonist pergolide: evidence from transcranial magnetic stimulation
Focal transcranial magnetic stimulation was used to evaluate the effect a single oral dose (0.125 mg) of the dopamine agonist pergolide on the excitability of the motor cortex in five healthy subjects. Resting and active motor thresholds of the abductor digiti minimi muscle were unaffected. The mean duration of the cortical silent period was significantly lengthened by up to 22
Ulf Ziemann; Dirk Bruns; Walter Paulus
Contralateral and ipsilateral EMG responses to transcranial magnetic stimulation during recovery of arm and hand function after stroke
We examined the relationship between the recovery of hand and arm function in a group of hemiplegic stroke patients and the presence of short-latency EMG responses to transcranial magnetic stimulation (TMS) in 4 different upper limb muscles (deltoid, biceps, extensor digitorum communis and the first dorsal interosseous). Twenty-one patients were examined within 5 weeks of stroke (median 2 weeks), and
A. Turton; S. Wroe; N. Trepte; C. Fraser; R. N. Lemon
Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research
This article is based on a consensus conference, which took place in Certosa di Pontignano, Siena (Italy) on March 7�9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings.Over the past decade the scientific and medical community has had the opportunity to evaluate the safety record of research
Simone Rossi; Mark Hallett; Paolo M. Rossini; Alvaro Pascual-Leone
Spinal Cord-Evoked Potentials and Muscle Responses Evoked by Transcranial Magnetic Stimulation in 10 Awake Human Subjects
Transcranial magnetic stimulation (TCMS) causes leg muscle contractions, but the neural structures in the brain that are activated by TCMS and their relationship to these leg muscle responses are not clearly understood. To elucidate this, we concomitantly recorded leg muscle responses and thoracic spinal cord-evoked potentials (SCEPs) after TCMS for the first time in 10 awake, neurologically intact human subjects.
David A. Houlden; Michael L. Schwartz; Charles H. Tator; Peter Ashby; William A. MacKay
Therapeutic applications of repetitive transcranial magnetic stimulation (rTMS) in movement disorders: a review.
Repetitive transcranial magnetic stimulation (rTMS) is emerging as a valuable adjunctive therapeutic modality in movement disorders. It is a non-invasive technique of repeated stimulation of the cerebral cortex by a train of magnetic pulses. The therapeutic effect of rTMS was first noted in depression. Later several researchers have investigated the role of rTMS in various movement disorders, notably Parkinson's disease, dystonia, Tourette's syndrome etc. The rTMS protocols used in these studies vary widely, lacks uniformity and often the results are not consistent. The optimal rTMS parameters for each disorder are yet to be established. This review discusses the current knowledge on the therapeutic applications of rTMS in various movement disorders. PMID:24726453
Kamble, Nitish; Netravathi, M; Pal, Pramod Kumar
[Exhaustion of motor cortex after head injury--revealed by transcranial magnetic stimulation].
We evaluated the pattern of motor evoked potentials elicited by single-pulse and slow-rate (1 Hz) repetitive, transcranial, magnetic stimulation (RTMS) in minor head injuries. The motor response to a single magnetic stimulus in patients with minor head injury was characterized by a significantly higher threshold than in healthy subjects. However, central and peripheral motor conduction was normal in all patients. A stable pattern of MEP throughout the RTMS session was the most prominent feature in the control group. A progressive decrease in MEP amplitude and irregular alternation of large and very small MEPs over the course of RTMS was observed in minor head injury. The higher threshold of the motor response and the abnormal patterns of MEP behavior revealed by RTMS may reflect impaired excitability and enhanced exhaustion of the motor cortex in patients with minor head injuries, which improve with time. PMID:10914237
Elron, M; Levi, G; Trovnick, M; Soustiel, J F; Hafner, H; Chistyakov, A; Feinsod, M
Plaque Volume Measurement by Magnetic Resonance Imaging as an Index of Remodeling of Middle Cerebral Artery: Correlation with Transcranial Color Doppler and Magnetic Resonance Angiography
Background: The feasibility of a noninvasive evaluation of remodeling of the middle cerebral artery (MCA) by magnetic resonance imaging (MRI) was assessed. The results were correlated with magnetic resonance angiography (MRA) and transcranial color Doppler (TCD) findings. Methods: 26 patients (13 male and 13 female, age ranged from 46 to 82 years) who presented with symptoms of cerebrovascular accidents had
W. W. M. Lam; K. S. Wong; N. M. C. So; T. K. Yeung; S. Gao
The Neural Bases of Word Encoding and Retrieval: A fMRI-Guided Transcranial Magnetic Stimulation Study
There is evidence that the human prefrontal cortex is asymmetrically involved in long-term episodic memory processing. Moreover,\\u000a abstract and concrete words processing has been reported to differentially involve prefrontal and parietal areas. We implemented\\u000a a two-stages functional magnetic resonance imaging (fMRI)�repetitive transcranial magnetic stimulation (rTMS) paradigm to\\u000a investigate the role of the dorsolateral prefrontal cortices (DLPFCs) and parietal cortices (PARCs)
R. Manenti; M. Tettamanti; M. Cotelli; C. Miniussi; S. F. Cappa
Remediation of Sleep-Deprivation-Induced Working Memory Impairment with fMRI-Guided Transcranial Magnetic Stimulation
Repetitive transcranial magnetic stimulation (rTMS) was applied to test the role of selected cortical regions in remediating sleep- deprivation--induced deficits in visual working memory (WM) performance. Three rTMS targets were chosen using a functional magnetic resonance imaging (fMRI)--identified network associated with sleep-deprivation--induced WM performance impairment: 2 regions from the network (upper left middle occipital gyrus and midline parietal cortex) and
B. Luber; A. D. Stanford; P. Bulow; T. Nguyen; B. C. Rakitin; C. Habeck; R. Basner; Y. Stern; S. H. Lisanby
Motor thresholds in humans: a transcranial magnetic stimulation study comparing different pulse waveforms, current directions and stimulator types
Objectives: To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex.Methods: In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid) and systematically varied current
Thomas Kammer; Sandra Beck; Axel Thielscher; Ulrike Laubis-Herrmann; Helge Topka
A method for estimation of stimulated brain sites based on columnar structure of cerebral cortex in transcranial magnetic stimulation
Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex. In TMS with a figure-of-eight coil, the induced electric field elicited by the pulsed magnetic fields is gathered beneath the center of the figure-of-eight coil, so the point on the cortex beneath the center of the figure-of-eight coil has been regarded as a stimulating site conventionally. However, the
Osamu Hiwaki; Tomonori Inoue
Simultaneous transcranial magnetic stimulation and single-neuron recording in alert non-human primates.
Transcranial magnetic stimulation (TMS) is a widely used, noninvasive method for stimulating nervous tissue, yet its mechanisms of effect are poorly understood. Here we report new methods for studying the influence of TMS on single neurons in the brain of alert non-human primates. We designed a TMS coil that focuses its effect near the tip of a recording electrode and recording electronics that enable direct acquisition of neuronal signals at the site of peak stimulus strength minimally perturbed by stimulation artifact in awake monkeys (Macaca mulatta). We recorded action potentials within ?1 ms after 0.4-ms TMS pulses and observed changes in activity that differed significantly for active stimulation as compared with sham stimulation. This methodology is compatible with standard equipment in primate laboratories, allowing easy implementation. Application of these tools will facilitate the refinement of next generation TMS devices, experiments and treatment protocols. PMID:24974797
Mueller, Jerel K; Grigsby, Erinn M; Prevosto, Vincent; Petraglia, Frank W; Rao, Hrishikesh; Deng, Zhi-De; Peterchev, Angel V; Sommer, Marc A; Egner, Tobias; Platt, Michael L; Grill, Warren M
State-dependent variability of neuronal responses to transcranial magnetic stimulation of the visual cortex
Summary Electrical brain stimulation is a promising tool for both experimental and clinical applications. However, the effects of stimulation on neuronal activity are highly variable and poorly understood. To investigate the basis of this variability, we performed extracellular recordings in the visual cortex following application of transcranial magnetic stimulation (TMS). Our measurements of spiking and local field potential activity exhibit two types of response patterns which are characterized by the presence or absence of spontaneous discharge following stimulation. This variability can be partially explained by state-dependent effects, in which higher pre-TMS activity predicts larger post-TMS responses. These results reveal the possibility that variability in the neural response to TMS can be exploited to optimize the effects of stimulation. It is conceivable that this feature could be utilized in real-time during the treatment of clinical disorders.
Pasley, Brian N.; Allen, Elena A.; Freeman, Ralph D.
Functional Neurosurgery in the Human Thalamus by Transcranial Magnetic Resonance Guided Focused Ultrasound
Potential applications of Transcranial Magnetic Resonance guided Focused Ultrasound (TcMRgFUS) include treatment of functional brain disorders, such as Parkinson's disease, dystonia and tremor, neurogenic pain and tinnitus, neuropsychiatric disorders and epilepsy. In this study we demonstrate the feasibility of non-invasive TcMRgFUS ablation of clinically well established targets in the human thalamus that are currently accessed stereotactically by interventional strategies based on the concept of the thalamocortical dysrhythmia (TCD). Thermal hotspots suitable for clinical intervention were created successfully in anatomical preparations of human ex-vivo heads under pseudo clinical conditions. The hotspots could be positioned at the target locations as needed and local energy deposition was sufficient to create tissue ablation. Numerical simulations based on these experimental data predict that the acoustic energy needed to create ablative lesions in-vivo will be within limits that can safely applied.
Werner, Beat; Morel, Anne; Jeanmonod, Daniel; Martin, Ernst
Neural field theory of calcium dependent plasticity with applications to transcranial magnetic stimulation.
Calcium dependent plasticity (CaDP), a physiologically realistic plasticity mechanism in the microscopic regime, is incorporated into a neural field theory to explore system-level plasticity. This system-level plasticity model is capable of reproducing the characteristic plasticity window of spike-timing dependent plasticity (STDP) in paired associative stimulation (PAS), where a peripheral electric pulse stimulation is paired to transcranial magnetic stimulation (TMS) in the cortex, and rTMS frequency dependent plasticity, where low and high frequency rTMS trains induce depression and potentiation, respectively. These thus reproduce experimental results for system-level plasticity for the first time. This also bridges the gap between microscopic plasticity theory and system-level plasticity observed experimentally, and addresses long standing problems of stability and adaptability by predicting stable plasticity, a possible seizure state where neurons fire at a high rate, and spike-rate adaptation. PMID:23376643
Fung, P K; Robinson, P A
The numeric calculation of eddy current distributions in transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) is a method to stimulate neurons in the brain. It is necessary to obtain eddy current distributions and determine parameters such as position, radius and bend-angle of the coil to stimulate target area exactly. In this study, we performed FEM-based numerical simulations of eddy current induced by TMS using three-dimentional human head model with inhomogeneous conductivity. We used double-cone coil and changed the coil radius and bend-angle of coil. The result of computer simulation showed that as coil radius increases, the eddy current became stronger everywhere. And coil with bend-angle of 22.5 degrees induced stronger eddy current than the coil with bendangle of 0 degrees. Meanwhile, when the bend-angle was 45 degrees, eddy current became weaker than these two cases. This simulation allowed us to determine appropriate parameter easier. PMID:19163660
Tsuyama, Seichi; Hyodo, Akira; Sekino, Masaki; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji
Dorsolateral prefrontal cortex, working memory and episodic memory processes: insight through transcranial magnetic stimulation techniques.
The ability to recall and recognize facts we experienced in the past is based on a complex mechanism in which several cerebral regions are implicated. Neuroimaging and lesion studies agree in identifying the frontal lobe as a crucial structure for memory processes, and in particular for working memory and episodic memory and their relationships. Furthermore, with the introduction of transcranial magnetic stimulation (TMS) a new way was proposed to investigate the relationships between brain correlates, memory functions and behavior. The aim of this review is to present the main findings that have emerged from experiments which used the TMS technique for memory analysis. They mainly focused on the role of the dorsolateral prefrontal cortex in memory process. Furthermore, we present state-of-the-art evidence supporting a possible use of TMS in the clinic. Specifically we focus on the treatment of memory deficits in depression and anxiety disorders. PMID:23385388
Balconi, Michela
A Study of Temporal Aspect of Posterior Parietal Cortex in Visual Search Using Transcranial Magnetic Stimulation
It is known that the posterior parietal cortex (PPC) plays a dominant role in spatial processing during visual search. However, the temporal aspect of the PPC is unclear. In the present study, to investigate the temporal aspects of the PPC in feature search, we applied Transcranial Magnetic Stimulation (TMS) over the right PPC with the TMS stimulus onset asynchronies (SOAs) set at 100, 150, 200 and 250 ms after visual search stimulation. We found that when SOA was set at 150 ms, compared to the sham TMS condition, there was a significant elevation in response time when TMS pulses were applied. However, there was no significant difference between the TMS and sham TMS conditions for the other SOA settings. Therefore, we suggest that the spatial processing of feature search is probably processed in the posterior parietal cortex at about 150-170 ms after visual search stimuli presentation.
Ge, Sheng; Matsuoka, Akira; Ueno, Shoogo; Iramina, Keiji
Repetitive transcranial magnetic stimulation to treat depression and insomnia with chronic low back pain.
Transcranial magnetic stimulation (TMS) is a noninvasive and safe technique for motor cortex stimulation. TMS is used to treat neurological and psychiatric disorders, including mood and movement disorders. TMS can also treat several types of chronic neuropathic pain. The pain relief mechanism of cortical stimulation is caused by modifications in neuronal excitability. Depression is a common co-morbidity with chronic pain. Pain and depression should be treated concurrently to achieve a positive outcome. Insomnia also frequently occurs with chronic lower back pain. Several studies have proposed hypotheses for TMS pain management. Herein, we report two cases with positive results for the treatment of depression and insomnia with chronic low back pain by TMS. PMID:25031816
Park, Eun Jung; Lee, Se Jin; Koh, Do Yle; Han, Yoo Mi
Transcranial magnetic stimulation: a historical evaluation and future prognosis of therapeutically relevant ethical concerns.
Transcranial Magnetic Stimulation (TMS) is a non-invasive neurostimulatory and neuromodulatory technique increasingly used in clinical and research practices around the world. Historically, the ethical considerations guiding the therapeutic practice of TMS were largely concerned with aspects of subject safety in clinical trials. While safety remains of paramount importance, the recent US Food and Drug Administration approval of the Neuronetics NeuroStar TMS device for the treatment of specific medication-resistant depression has raised a number of additional ethical concerns, including marketing, off-label use and technician certification. This article provides an overview of the history of TMS and highlights the ethical questions that are likely arise as the therapeutic use of TMS continues to expand. PMID:21106996
Horvath, Jared C; Perez, Jennifer M; Forrow, Lachlan; Fregni, Felipe; Pascual-Leone, Alvaro
Assessment and modulation of neural plasticity in rehabilitation with transcranial magnetic stimulation.
Despite intensive efforts to improve outcomes after acquired brain injury, functional recovery is often limited. One reason for this limitation is the challenge in assessing and guiding plasticity after brain injury. In this context, transcranial magnetic stimulation (TMS), a noninvasive tool of brain stimulation, could play a major role. TMS has been shown to be a reliable tool for measuring plastic changes in the motor cortex associated with interventions in the motor system, such as motor training and motor cortex stimulation. In addition, as illustrated by the experience in promoting recovery from stroke, TMS is a promising therapeutic tool to minimize motor, speech, cognitive, and mood deficits. In this review, we will focus on stroke to discuss how TMS can provide insights into the mechanisms of neurologic recovery and how it can be used for measurement and modulation of plasticity after an acquired brain insult. PMID:21172687
Bashir, Shahid; Mizrahi, Ilan; Weaver, Kayleen; Fregni, Felipe; Pascual-Leone, Alvaro
Maintaining remission of depression with repetitive transcranial magnetic stimulation during pregnancy: a case report.
It is important to explore potential safe treatment options for the ongoing treatment of women's depression during pregnancy. One promising treatment is repetitive transcranial magnetic stimulation (rTMS). We report on the case of a woman who became pregnant while receiving regular maintenance rTMS combined with pharmacotherapy treatment for major depressive episode. The patient achieved remission following two acute courses of rTMS and continued with maintenance rTMS treatment over the course of 4�years, during which she became pregnant and gave birth to a healthy infant. Her remission was maintained over this time including during and after her pregnancy. There were no adverse effects to the patient or her infant during the pregnancy or in the post-natal period. Maintenance rTMS may be an effective and feasible treatment option for depression during pregnancy. PMID:24638141
Burton, Cassandra; Gill, Shane; Clarke, Patrick; Galletly, Cherrie
Transient suppression of seizures by repetitive transcranial magnetic stimulation in a case of Rasmussen's encephalitis
Repetitive transcranial magnetic stimulation (rTMS) has been applied with variable success to terminate the seizures of epilepsia partialis continua. The rationale for using this technique to suppress ongoing seizures is the capacity of rTMS to interrupt ongoing neuronal activity, and to produce a lasting decrease in cortical excitability with low-frequency (?1 Hz) stimulation. We report a case of epilepsia partialis continua in a child with Rasmussen�s encephalitis, in whom seizures were transiently suppressed by 1-Hz rTMS delivered in nine daily 30-minute sessions. In this case, total ictal time was significantly reduced during stimulation, but the daily baseline seizure rate remained unchanged. Notably, the detection and quantification of this short-lived improvement were enabled by recording EEG continuously during the rTMS session. Thus, we present this case to illustrate a potential utility of combined continuous EEG recording and rTMS in seizure treatment.
Rotenberg, Alexander; Depositario-Cabacar, Dewi; Bae, Erica Hyunji; Harini, Chellamani; Pascual-Leone, Alvaro; Takeoka, Masanori
Transcranial magnetic stimulation of posterior parietal cortex affects decisions of hand choice
Deciding which hand to use for an action is one of the most frequent decisions people make in everyday behavior. Using a speeded reaching task, we provide evidence that hand choice entails a competitive decision process between simultaneously activated action plans for each hand. We then show that single-pulse transcranial magnetic stimulation to the left posterior parietal cortex biases this competitive process, leading to an increase in ipsilateral, left hand reaches. Stimulation of the right posterior parietal cortex did not alter hand choice, suggesting a hemispheric asymmetry in the representations of reach plans. These results are unique in providing causal evidence that the posterior parietal cortex is involved in decisions of hand choice.
Oliveira, Flavio T. P.; Diedrichsen, Jorn; Verstynen, Timothy; Duque, Julie; Ivry, Richard B.
Navigated transcranial magnetic stimulation in preoperative planning for the treatment of motor area cavernous angiomas
Since the introduction of microscopic techniques, radical surgery for cavernous angiomas has become a recommended treatment option. However, the treatment of motor area cavernous angioma represents a great challenge for the surgical team. Here, we describe an approach guided by frameless neuronavigation and preoperative functional mapping with transcranial magnetic stimulation (TMS), for surgical planning. We used TMS to map the motor cortex and its relationship with the angioma. We achieved complete resection of the lesions in the surgeries, while avoiding areas of motor response identified during the preoperative mapping. We verified the complete control of seizures (Engel class 1A) in the patients with previous refractory epilepsy. Postsurgery, one patient was seizure-free without medication, and two patients required only one medication for seizure control. Thus, navigated TMS appears to be a useful tool, in preoperative planning for cavernous angiomas of the motor area.
Paiva, Wellingson Silva; Fonoff, Erich Talamoni; Marcolin, Marco Antonio; Bor-Seng-Shu, Edson; Figueiredo, Eberval Gadelha; Teixeira, Manoel Jacobsen
Chronic repetitive transcranial magnetic stimulation induces subsensitivity of presynaptic serotonergic autoreceptor activity in rat brain.
Repetitive transcranial magnetic stimulation (rTMS) is a novel procedure which has proven effective in the treatment of major depression. We administered rTMS chronically to rats in order to determine whether this procedure affected serotonergic neurotransmission in the prefrontal cortex. Basal 5-HT levels, and the effects of challenges with the 5-HT1A receptor agonist 8-OH-DPAT and the 5-HT1B antagonist GR 127935 on 5-HT levels were determined using in vivo microdialysis. Rats which had undergone chronic rTMS showed reduced responses to both challenges, indicating subsensitivity of both the presynaptic 5-HT1A autoreceptors situated somatodendritically in the raphe nuclei and the 5-HT1B autoreceptors situated on nerve terminals. Since such subsensitivity has been demonstrated after other antidepressant treatments, our results indicate that these treatments and rTMS may have a common mechanism of action. PMID:11006967
Gur, E; Lerer, B; Dremencov, E; Newman, M E
Repetitive Transcranial Magnetic Stimulation to Treat Depression and Insomnia with Chronic Low Back Pain
Transcranial magnetic stimulation (TMS) is a noninvasive and safe technique for motor cortex stimulation. TMS is used to treat neurological and psychiatric disorders, including mood and movement disorders. TMS can also treat several types of chronic neuropathic pain. The pain relief mechanism of cortical stimulation is caused by modifications in neuronal excitability. Depression is a common co-morbidity with chronic pain. Pain and depression should be treated concurrently to achieve a positive outcome. Insomnia also frequently occurs with chronic lower back pain. Several studies have proposed hypotheses for TMS pain management. Herein, we report two cases with positive results for the treatment of depression and insomnia with chronic low back pain by TMS.
Park, Eun Jung; Koh, Do Yle; Han, Yoo Mi
A transcranial magnetic stimulator inducing near-rectangular pulses with controllable pulse width (cTMS).
A novel transcranial magnetic stimulation (TMS) device with controllable pulse width (PW) and near-rectangular pulse shape (cTMS) is described. The cTMS device uses an insulated gate bipolar transistor (IGBT) with appropriate snubbers to switch coil currents up to 6 kA, enabling PW control from 5 micros to over 100 micros. The near-rectangular induced electric field pulses use 2%-34% less energy and generate 67%-72% less coil heating compared to matched conventional cosine pulses. CTMS is used to stimulate rhesus monkey motor cortex in vivo with PWs of 20 to 100 micros, demonstrating the expected decrease of threshold pulse amplitude with increasing PW. The technological solutions used in the cTMS prototype can expand functionality, and reduce power consumption and coil heating in TMS, enhancing its research and therapeutic applications. PMID:18232369
Peterchev, Angel V; Jalinous, Reza; Lisanby, Sarah H
The use of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) to relieve pain.
Chronic pain resulting from injury of the peripheral or central nervous system may be associated with a significant dysfunction of extensive neural networks. Noninvasive stimulation techniques, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) may be suitable to treat chronic pain as they can act on these networks by modulating neural activities not only in the stimulated area, but also in remote regions that are interconnected to the site of stimulation. Motor cortex was the first cortical target that was proved to be efficacious in chronic pain treatment. At present, significant analgesic effects were also shown to occur after the stimulation of other cortical targets (including prefrontal and parietal areas) in acute provoked pain, chronic neuropathic pain, fibromyalgia, or visceral pain. Therapeutic applications of rTMS in pain syndromes are limited by the short duration of the induced effects, but prolonged pain relief can be obtained by repeating rTMS sessions every day for several weeks. Recent tDCS studies also showed some effects on various types of chronic pain. We review the evidence to date of these two techniques of noninvasive brain stimulation for the treatment of pain. PMID:20633392
Lefaucheur, Jean-Pascal; Antal, Andrea; Ahdab, Rechdi; Ciampi de Andrade, Daniel; Fregni, Felipe; Khedr, Eman M; Nitsche, Michael; Paulus, Walter
Applications of transcranial magnetic stimulation and magnetic seizure therapy in the study and treatment of disorders related to cerebral aging
Transcranial magnetic stimulation (TMS) can be used to probe cortical function and treat neuropsychiatric illnesses. TMS has demonstrated neuroplastic effects akin to long-term potentiation and long-term depression, and therapeutic applications are in development for post-stroke recovery, Alzheimer's disease, and depression in seniors. Here, we discuss two new directions of TMS research relevant to cerebral aging and cognition. First, we introduce a paradigm for enhancing cognitive reserve, based on our research in sleep deprivation. Second, we discuss the use of magnetic seizure therapy (MST) to spare cognitive functions relative to conventional electroconvulsive therapy, and as a means of providing a more potent antidepressant treatment when subconvulsive TMS has shown modest efficacy in seniors. Whether in the enhancement of cognition as a treatment goal, or in the reduction of amnesia as a side effect, these approaches to the use of TMS and MST merit further exploration regarding their clinical potential.
Luber, Bruce; McClintock, Shawn M.; Lisanby, Sarah H.
Risk and safety of repetitive transcranial magnetic stimulation: report and suggested guidelines from the International Workshop on the Safety of Repetitive Transcranial Magnetic Stimulation, June 5�7, 1996
Single-pulse transcranial magnetic stimulation (TMS) is a safe and useful tool for investigating various aspects of human neurophysiology, particularly corticospinal function, in health and disease. Repetitive TMS (rTMS), however, is a more powerful and potentially dangerous modality, capable of regionally blocking or facilitating cortical processes. Although there is evidence that rTMS is useful for treating clinical depression, and possibly other
Eric M. Wassermann
A structurally detailed finite element human head model for simulation of transcranial magnetic stimulation.
Computational studies of the head utilizing finite element models (FEMs) have been used to investigate a wide variety of brain-electromagnetic (EM) field interaction phenomena including magnetic stimulation of the head using transcranial magnetic stimulation (TMS), direct electric stimulation of the brain for electroconvulsive therapy, and electroencephalography source localization. However, no human head model of sufficient complexity for studying the biophysics under these circumstances has been developed which utilizes structures at both the regional and cellular levels and provides well-defined smooth boundaries between tissues of different conductivities and orientations. The main barrier for building such accurate head models is the complex modeling procedures that include 3D object reconstruction and optimized meshing. In this study, a structurally detailed finite element model of the human head was generated that includes details to the level of cerebral gyri and sulci by combining computed tomography and magnetic resonance images. Furthermore, cortical columns that contain conductive processes of pyramidal neurons traversing the neocortical layers were included in the head model thus providing structure at or near the cellular level. These refinements provide a much more realistic model to investigate the effects of TMS on brain electrophysiology in the neocortex. PMID:19428517
Chen, Ming; Mogul, David Jeffery
Transcranial magnetic stimulation of mouse brain using high-resolution anatomical models
Transcranial magnetic stimulation (TMS) offers the possibility of non-invasive treatment of brain disorders in humans. Studies on animals can allow rapid progress of the research including exploring a variety of different treatment conditions. Numerical calculations using animal models are needed to help design suitable TMS coils for use in animal experiments, in particular, to estimate the electric field induced in animal brains. In this paper, we have implemented a high-resolution anatomical MRI-derived mouse model consisting of 50 tissue types to accurately calculate induced electric field in the mouse brain. Magnetic field measurements have been performed on the surface of the coil and compared with the calculations in order to validate the calculated magnetic and induced electric fields in the brain. Results show how the induced electric field is distributed in a mouse brain and allow investigation of how this could be improved for TMS studies using mice. The findings have important implications in further preclinical development of TMS for treatment of human diseases.
Crowther, L. J.; Hadimani, R. L.; Kanthasamy, A. G.; Jiles, D. C.
Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex
To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.
Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji
Transcranial magnetic stimulation: a neuroscientific probe of cortical function in schizophrenia.
Transcranial magnetic stimulation (TMS) is a neuropsychiatric tool that can serve as a useful method to better understand the neurobiology of cognitive function, behavior, and emotional processing. The purpose of this article is to examine the utility of TMS as a means to measure neocortical function in neuropsychiatric disorders in general, and schizophrenia in particular, for the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia initiative. When incorporating TMS paradigms in research studies, methodologic considerations include technical aspects of TMS, cohort selection and confounding factors, and subject safety. Available evidence suggests benefits of TMS alone or in combination with neurophysiologic and neuroimaging methods, including positron emission tomography, single photon emission computed tomography, magnetic resonance imaging, functional magnetic resonance imaging, functional near infrared spectroscopy, magnetoencephalography, and electroencephalography, to explore neocortical function. With the multiple TMS techniques including single-pulse, paired-pulse, paired associative stimulation, and repetitive TMS and theta burst stimulation, combined with neurophysiologic and neuroimaging methods, there exists a plethora of TMS experimental paradigms to modulate neocortical physiologic processes. Specifically, TMS can measure cortical excitability, intracortical inhibitory and excitatory mechanisms, and local and network cortical plasticity. Coupled with functional and electrophysiologic modalities, TMS can provide insight into the mechanisms underlying healthy neurodevelopment and aging, as well as neuropsychiatric pathology. Thus, TMS could be a useful tool in the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia armamentarium of biomarker methods. Future investigations are warranted to optimize TMS methodologies for this purpose. PMID:21571254
McClintock, Shawn M; Freitas, Catarina; Oberman, Lindsay; Lisanby, Sarah H; Pascual-Leone, Alvaro
Combining transcranial magnetic stimulation and FMRI to examine the default mode network.
The default mode network is a group of brain regions that are active when an individual is not focused on the outside world and the brain is at "wakeful rest." It is thought the default mode network corresponds to self-referential or "internal mentation". It has been hypothesized that, in humans, activity within the default mode network is correlated with certain pathologies (for instance, hyper-activation has been linked to schizophrenia and autism spectrum disorders whilst hypo-activation of the network has been linked to Alzheimer's and other neurodegenerative diseases. As such, noninvasive modulation of this network may represent a potential therapeutic intervention for a number of neurological and psychiatric pathologies linked to abnormal network activation. One possible tool to effect this modulation is Transcranial Magnetic Stimulation: a non-invasive neurostimulatory and neuromodulatory technique that can transiently or lastingly modulate cortical excitability (either increasing or decreasing it) via the application of localized magnetic field pulses. In order to explore the default mode network's propensity towards and tolerance of modulation, we will be combining TMS (to the left inferior parietal lobe) with functional magnetic resonance imaging (fMRI). Through this article, we will examine the protocol and considerations necessary to successfully combine these two neuroscientific tools. PMID:21248684
Halko, Mark A; Eldaief, Mark C; Horvath, Jared C; Pascual-Leone, Alvaro
Reproducibility of callosal effects of transcranial magnetic stimulation (TMS) with interhemispheric paired pulses.
Transcranial magnetic stimulation (TMS) of the motor cortex of one hemisphere (conditioning stimulus (CS)) inhibits EMG responses evoked in distal hand muscles by a later magnetic stimulus given at an appropriate interval, over the opposite hemisphere (test stimulus (TS)). This effect is commonly attributed to an inhibition produced at cortical level via a transcallosal route. The present study assessed the reproducibility of the transcallosal inhibition effects in different sessions in healthy subjects. Within- and between-subject variability, relating to interhemispheric differences was also evaluated. A magnetic CS on one hemisphere effectively inhibited EMG responses of the abductor digiti minimi stimulated by a TS delivered over the opposite hemisphere in a range of intervals centered at 12 ms. Even though group effects were reproduced in separate sessions, the high between- and within-subject variability yielded low test-retest correlations. This differentiation forces the definition of reproducibility (or repeatability), as the replication of the same mean curves of EMG reduction, and of reliability, as the between- or within-subject correlations between values of specific EMG measures. PMID:12767485
De Gennaro, Luigi; Ferrara, Michele; Bertini, Mario; Pauri, Flavia; Cristiani, Riccardo; Curcio, Giuseppe; Romei, Vincenzo; Fratello, Fabiana; Rossini, Paolo Maria
flexTMS--a novel repetitive transcranial magnetic stimulation device with freely programmable stimulus currents.
Transcranial magnetic stimulation (TMS) is able to noninvasively excite neuronal populations due to brief magnetic field pulses. The efficiency and the characteristics of stimulation pulse shapes influence the physiological effect of TMS. However, commercial devices allow only a minimum of control of different pulse shapes. Basically, just sinusoidal and monophasic pulse shapes with fixed pulse widths are available. Only few research groups work on TMS devices with controllable pulse parameters such as pulse shape or pulse width. We describe a novel TMS device with a full-bridge circuit topology incorporating four insulated-gate bipolar transistor (IGBT) modules and one energy storage capacitor to generate arbitrary waveforms. This flexible TMS (flexTMS ) device can generate magnetic pulses which can be adjusted with respect to pulse width, polarity, and intensity. Furthermore, the equipment allows us to set paired pulses with a variable interstimulus interval (ISI) from 0 to 20�ms with a step size of 10� ?s. All user-defined pulses can be applied continually with repetition rates up to 30 pulses per second (pps) or, respectively, up to 100�pps in theta burst mode. Offering this variety of flexibility, flexTMS will allow the enhancement of existing TMS paradigms and novel research applications. PMID:22531742
Gattinger, Norbert; Moessnang, Georg; Gleich, Bernhard
[Changes in the responses of motor units to transcranial magnetic stimulation in patients with multiple sclerosis and stroke].
In multiple sclerosis and stroke the muscle responses to transcranial magnetic stimulation are frequently delayed, reduced in amplitude or absent. To investigate the underlying pathophysiological mechanisms, responses of single motor units to transcranial magnetic stimulation were analysed using peri-stimulus time histograms. The following response patterns were detected: 1. prolongation of latency and duration of the primary peak which occurs in healthy controls 17 to 30 ms after the stimulus and has a duration of 2 to 8 ms, 2. lack of an excitatory response, 3. prolongation of the interval between sub-peaks within the primary peak and 4. multimodal responses. Possible mechanisms for these changes are: reduction and dispersion of conduction velocities in corticospinal axons associated with impaired summation of excitatory post-synaptic potentials at the spinal motoneurone, frequency-dependent or complete conduction block in corticospinal neurones and compensatory activation of other descending motor pathways. PMID:1864246
Schubert, M; Mills, K R; Boniface, S J; Konstanzer, A; Dengler, R
Induction of central nervous system plasticity by repetitive transcranial magnetic stimulation to promote sensorimotor recovery in incomplete spinal cord injury
Cortical and spinal cord plasticity may be induced with non-invasive transcranial magnetic stimulation to encourage long term potentiation or depression of neuronal circuits. Such plasticity inducing stimulation provides an attractive approach to promote changes in sensorimotor circuits that have been degraded by spinal cord injury (SCI). If residual corticospinal circuits can be conditioned appropriately there should be the possibility that the changes are accompanied by functional recovery. This article reviews the attempts that have been made to restore sensorimotor function and to obtain functional benefits from the application of repetitive transcranial magnetic stimulation (rTMS) of the cortex following incomplete spinal cord injury. The confounding issues that arise with the application of rTMS, specifically in SCI, are enumerated. Finally, consideration is given to the potential for rTMS to be used in the restoration of bladder and bowel sphincter function and consequent functional recovery of the guarding reflex.
Ellaway, Peter H.; Vasquez, Natalia; Craggs, Michael
Time-dependent effects of low-frequency repetitive transcranial magnetic stimulation of the supramarginal gyrus.
In this paper, we report our studies of the effects of stimulating the bilateral supramarginal gyrus (SMG) with low-frequency transcranial magnetic stimulation (rTMS) or short-term rTMS on brain excitability in humans. We analyzed the effects of various durations of stimulation on P300 latencies of the event-related potential (ERP). Magnetic pulses were delivered using a figure-eight flat coil. The intensity of rTMS was set to 80 % of the subject's motor threshold. In each round of rTMS, 100 magnetic pulses were applied over the scalp at frequencies of 1.00, 0.75, and 0.50 Hz. ERPs were measured prior to magnetic stimulation as a control. The effects of magnetic stimulation were then determined by measuring its effects on P300 latencies elicited by an odd-ball task. These latencies were measured before and 0, 5, 10, and 15 min after the magnetic stimulation. 1.00 Hz low-frequency rTMS of the left SMG decreased P300 latencies for approximately 10 min. In contrast, 0.50 Hz rTMS of the left SMG resulted in delayed P300 latencies for approximately 15 min. We furthermore found that 0.75 Hz rTMS of the left SMG and 1.00, 0.75 and 0.5 Hz rTMS of the right SMG did not affect P300 latencies. These results suggest that the duration of the effects of rTMS depend on the frequency of stimulation. PMID:23366649
Torii, T; Sato, A; Iwahashi, M; Itoh, Y; Iramina, K
Combined functional magnetic resonance imaging and transcranial magnetic stimulation evidence of ipsilateral motor pathway with congenital brain disorder: A case report
Jang SH, Byun WM, Chang Y, Han BS, Ahn SH. Combined functional magnetic resonance imaging and transcranial magnetic stimulation evidence of ipsilateral motor pathway with congenital brain disorder: a case report. Arch Phys Med Rehabil 2001;82:1733-6. We present the case of 28-year-old man with schizencephaly who had mild left hemiparesis with mirror movement. Brain mapping using functional magnetic resonance imaging
Sung Ho Jang; Woo Mok Byun; Yongmin Chang; Bong Soo Han; Sang Ho Ahn
Transcranial Magnetic Stimulation of the Posterior Parietal Cortex Degrades Accuracy of Memory-Guided Saccades in Humans
Purpose. Previous neurophysiological studies in the monkey have shown that the posterior parietal cortex (PPC) is involved in the control of memory-guided saccades. In this study, the authors investigated the effect of focal transcranial magnetic stimulation (TMS) over the posterior parietal cortex on accuracy of memory-guided saccades in humans to clarify the cortical region related to controlling memory-guided saccades. Methods.
Hiroaki Oyachi; Kenji Ohtsuka
Effects of repetitive transcranial magnetic stimulation over dorsolateral prefrontal and posterior parietal cortex on memory-guided saccades
We investigated the role of the dorsolateral prefrontal cortex (DLPFC) and the posterior parietal cortex (PPC) in a visuospatial\\u000a delayed-response task in humans. Repetitive transcranial magnetic stimulation (20?Hz, 0.5?s) was used to interfere temporarily\\u000a with cortical activity in the DLPFC and PPC during the delay period. Omnidirectional memory-guided saccades with a 3-s delay\\u000a were used as a quantifiable motor response
Stephan A. Brandt; Christoph J. Ploner; Bernd-Ulrich Meyer; Stefanie Leistner; Arno Villringer
Short-term memory: no evidence of effect of rapid-repetitive transcranial magnetic stimulation in healthy individuals
The effect of rapid-repetitive transcranial magnetic stimulation (rr-TMS) on the immediate verbal and visuospatial memory span was assessed by computerized neuropsychological testing in 11 healthy volunteers. The objective was to test whether rr-TMS may be utilized as a non-invasive tool for evaluation of memory function. The subjects had to memorize series of numbers (Digit-Span test) or the position of cubes
Andreas Hufnagel; Detlef Clause; Christoph Brunhoelzl; Thomas Sudhop
A Review of Transcranial Magnetic Stimulation in the in vivo Functional Evaluation of Central Cholinergic Circuits in Dementia
Central cholinergic circuits of human brain can be tested non-invasively by coupling electrical peripheral stimulation with transcranial magnetic stimulation (TMS) of the motor cortex. The short-latency afferent inhibition (SAI) is reduced in cholinergic forms of dementia, such as Alzheimer disease (AD) and dementia with Lewy bodies, while it is normal in non-cholinergic forms of dementia, such as frontotemporal dementia. This
Raffaele Nardone; Stefan Golaszewski; Gunther Ladurner; Frediano Tezzon; Eugen Trinka
Probing the involvement of the right hemisphere in language processing with online transcranial magnetic stimulation in healthy volunteers
Background: Current models emphasize that language-related functions are predominantly organized in left-lateralized fronto-temporo-parietal cortical networks.Aims: In this review, we summarize how �online� transcranial magnetic stimulation (TMS) during a language task can be used in healthy individuals to characterize the contribution of the stimulated area to a specific language function with a focus on the functional relevance of the right hemisphere.
Gesa Hartwigsen; Hartwig R. Siebner
Transcranial Magnetic Stimulation of the Prefrontal Cortex: A Complementary Approach to Investigate Human Long-Term Memory
Repetitive transcranial magnetic stimulation (rTMS) can noninvasively and focally stimulate the cerebral cortex, inducing\\u000a a transient and safe interruption of brain function. Although its detailed mechanisms of action still need to be fully elucidated,\\u000a it has been successfully applied to investigate encoding and retrieval phases during episodic long-term memory tasks, both\\u000a in the visuospatial and verbal domains. The effects of
Simone Rossi; Carlo Miniussi; Paolo Maria Rossini; Claudio Babiloni; Stefano Cappa
Transcranial magnetic stimulation (TMS) applied to left dorsolateral prefrontal cortex disrupts verbal working memory performance in humans
Working memory refers to the temporary maintenance and processing of information and involves executive processes that manipulate the contents of the working memory. The role of the executive function in the human left dorsolateral prefrontal cortex (LDLPFC) was explored using transcranial magnetic stimulation (TMS) after confirming the LDLPFC activation using fMRI. We applied double-pulse TMS having a 100-ms inter-pulse interval
Naoyuki Osaka; Yuki Otsuka; Nobuyuki Hirose; Takashi Ikeda; Tatsuya Mima; Hidenao Fukuyama; Mariko Osaka
Effects of attention on inhibitory and facilitatory phenomena elicited by paired-pulse transcranial magnetic stimulation in healthy subjects
We investigated whether human attentional processes influence the activity of intracortical inhibitory and excitatory circuits�short-interval\\u000a intracortical inhibition (SICI), long-interval intracortical inhibition (LICI), and the intracortical facilitation (ICF)�elicited\\u000a by paired-pulse transcranial magnetic stimulation (TMS) in healthy subjects. In eight healthy subjects we tested SICI, LICI\\u000a and ICF under different attention-demanding conditions: �relaxed�, �target hand� and �non-target hand�. To compare the effects
Antonella Conte; Daniele Belvisi; Ennio Iezzi; Francesco Mari; Maurizio Inghilleri; Alfredo Berardelli
The right dorsolateral prefrontal cortex is essential in time reproduction: an investigation with repetitive transcranial magnetic stimulation
This study used repetitive transcranial magnetic stimulation (rTMS) to investigate the roles of the right dorsolateral prefrontal cortex (DLPFC) and supplementary motor area (SMA) in short (500�ms) and long (2�s) interval timing. The results were compared with rTMS over the leg area of motor cortex, an area not thought to be involved with time estimation. rTMS was delivered during one
Catherine R. G. Jones; Karin Rosenkranz; John C. Rothwell; Marjan Jahanshahi
Mechanisms of Action Underlying the Effect of Repetitive Transcranial Magnetic Stimulation on Mood: Behavioral and Brain Imaging Studies
In a set of experiments, we applied 10-Hz repetitive transcranial magnetic stimulation (rTMS) over the left mid-dorsolateral frontal cortex (MDLFC) to investigate rTMS-induced changes in affective state and neural activity in healthy volunteers. In Experiment 1, we combined 10-Hz rTMS with a speech task to examine rTMS-induced changes in paralinguistic aspects of speech production, an affect-relevant behavior strongly linked to
Jennifer Barrett; Valeria Della-Maggiore; Philippe A Chouinard; Tom� Paus
SHORT COMMUNICATION Double-pulse transcranial magnetic stimulation over the frontal eye field facilitates triggering of memory-guided saccades
The study investigated the influence of double-pulse transcranial magnetic stimulation (dTMS) on memory-guided saccade triggering. Double pulses with interstimulus intervals (ISIs) of 35, 50, 65 or 80 ms were applied over the right frontal eye field (FEF) and as control over the occipital cortex. A significant dTMS effect was found exclusively for contralateral saccades; latency of memory-guided saccades was reduced
Marius Wipfli; Jacques Felblinger; Urs P. Mosimann; Christian W. Hess; Thomas E. Schlaepfer
Evaluating the role of prefrontal and parietal cortices in memory-guided response with repetitive transcranial magnetic stimulation
The dorsolateral prefrontal cortex (dlPFC) plays an important role in working memory, including the control of memory-guided response. In this study, with 24 subjects, we used high frequency repetitive transcranial magnetic stimulation (rTMS) to evaluate the role of the dlPFC in memory-guided response to two different types of spatial working memory tasks: one requiring a recognition decision about a probe
Subthreshold 5Hz repetitive transcranial magnetic stimulation of the human primary motor cortex reduces intracortical paired-pulse inhibition
Paired-pulse transcranial magnetic stimulation (TMS) at short interstimulus intervals was employed to investigate short-term effects of 5-Hz repetitive TMS (rTMS) over the primary motor hand area (M1HAND) on intracortical excitability. In ten healthy individuals, 1250 pulses of 5-Hz rTMS were applied at 90% of motor resting threshold over the left M1HAND. Ten minutes after 5-Hz rTMS, paired-pulse inhibition was significantly
Alexander Peinemann; Christian Lehner; Claudia Mentschel; Alexander M�nchau; Bastian Conrad; Hartwig Roman Siebner
Preferential activation of different I waves by transcranial magnetic stimulation with a figure-of-eight-shaped coil
Transcranial magnetic stimulation (TMS) over the human primary motor cortex (M1) evokes motor responses in the contralateral\\u000a limb muscles. The latencies and amplitudes of those responses depend on the direction of induced current in the brain by the\\u000a stimuli (Mills et al. 1992, Werhahn et al. 1994). This observation suggests that different neural elements might be activated\\u000a by the differently
Katsuyuki Sakai; Yoshikazu Ugawa; Yasuo Terao; Ritsuko Hanajima; Toshiaki Furubayashi; Ichiro Kanazawa
Safety of different inter-train intervals for repetitive transcranial magnetic stimulation and recommendations for safe ranges of stimulation parameters
Induction of a seizure in a normal subject with trains of repetitive transcranial magnetic stimulation (rTMS) applied in close succession suggested that short inter-train intervals, a parameter not considered in our previous safety studies, may not be safe. Here, we evaluate the safety of different inter-train intervals for rTMS in 10 healthy volunteers. Ten rTMS trains at 20 Hz for
Robert Chen; Christian Gerloff; Joseph Classen; Eric M Wassermann; Mark Hallett; Leonardo G. Cohen
A randomized controlled comparison of electroconvulsive therapy and repetitive transcranial magnetic stimulation in severe and resistant nonpsychotic major depression
BackgroundStudies published over the past few years suggest that transcranial magnetic stimulation (TMS) may have significant antidepressant actions. In a previous report, we compared electroconvulsive therapy (ECT) and repetitive TMS (rTMS) and found ECT to be superior for psychotic major depression (MD); however, ECT and rTMS had similar results in nonpsychotic MD. We now report on a controlled randomized comparison
Leon Grunhaus; Shaul Schreiber; Ornah T Dolberg; Dana Polak; Pinhas N Dannon
Low frequency transcranial magnetic stimulation on the posterior parietal cortex induces visuotopically specific neglect-like syndrome
The visuo-parietal (VP) region of the cerebral cortex is critically involved in the generation of orienting responses towards visual stimuli. In this study we use repetitive transcranial magnetic stimulation (rTMS) to unilaterally and non-invasively deactivate the VP cortex during a simple spatial visual detection task tested in real space. Adult cats were intensively trained over 4�months on a task requiring
A. Valero-Cabr�; R. J. Rushmore; B. R. Payne
Immediate plasticity in the motor pathways after spinal cord hemisection: implications for transcranial magnetic motor-evoked potentials
The present study evaluates motor functional recovery after C2 spinal cord hemisection with or without contralateral brachial root transection, which causes a condition that is similar to the crossed phrenic phenomenon on rats. Descending motor pathways, including the reticulospinal extrapyramidal tract and corticospinal pyramidal tracts, were evaluated by transcranial magnetic motor-evoked potentials (mMEPs) and direct cortical electrical motor-evoked potentials (eMEP),
Minoru Fujiki; Hidenori Kobayashi; Ryo Inoue; Keisuke Ishii
Theta burst transcranial magnetic stimulation for the treatment of auditory verbal hallucinations: results of a randomized controlled study.
One Hertz (1 Hz) repetitive transcranial magnetic stimulation (rTMS) is an effective therapy for auditory verbal hallucinations (AVH). Theta burst protocols (TBS) show longer after-effects. This single-blind, randomized controlled study compared continuous TBS with 1Hz rTMS in a 10-day treatment. Patients were diagnosed with schizophrenia or schizoaffective disorder. TBS demonstrated equal clinical effects compared to 1Hz TMS. PMID:23648282
Kindler, Jochen; Homan, Philipp; Flury, Richard; Strik, Werner; Dierks, Thomas; Hubl, Daniela
Brain-derived neurotrophic factor serum concentrations in depressive patients during vagus nerve stimulation and repetitive transcranial magnetic stimulation
Background��Vagus nerve stimulation (VNS) and repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex are brain stimulation techniques used as therapeutic interventions in major depression.Methods��In this study, we report the impact of these stimulation techniques on serum concentrations of brain-derived neurotrophic factor (BDNF) in treatment-resistant patients with a diagnosis of major depression.Results��We found no changes of BDNF serum concentrations
Undine E. Lang; Malek Bajbouj; Juergen Gallinat; Rainer Hellweg
Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300
The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.
Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji
Modulation of EEG functional connectivity networks in subjects undergoing repetitive transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique that utilizes magnetic fluxes to alter cortical activity. Continuous theta-burst repetitive TMS (cTBS) results in long-lasting decreases in indices of cortical excitability, and alterations in performance of behavioral tasks. We investigated the effects of cTBS on cortical function via functional connectivity and graph theoretical analysis of EEG data. Thirty-one channel resting-state EEG recordings were obtained before and after 40�s of cTBS stimulation to the left primary motor cortex. Functional connectivity between nodes was assessed in multiple frequency bands using lagged max-covariance, and subsequently thresholded to construct undirected graphs. After cTBS, we find widespread decreases in functional connectivity in the alpha band. There are also simultaneous increases in functional connectivity in the high-beta bands, especially amongst anterior and interhemispheric connections. The analysis of the undirected graphs reveals that interhemispheric and interregional connections are more likely to be modulated after cTBS than local connections. There is also a shift in the topology of network connectivity, with an increase in the clustering coefficient after cTBS in the beta bands, and a decrease in clustering and increase in path length in the alpha band, with the alpha-band connectivity primarily decreased near the site of stimulation. cTBS produces widespread alterations in cortical functional connectivity, with resulting shifts in cortical network topology. PMID:23471637
Shafi, Mouhsin M; Brandon Westover, M; Oberman, Lindsay; Cash, Sydney S; Pascual-Leone, Alvaro
Modulation of EEG Functional Connectivity Networks in Subjects Undergoing Repetitive Transcranial Magnetic Stimulation
Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique that utilizes magnetic fluxes to alter cortical activity. Continuous theta-burst repetitive TMS (cTBS) results in long-lasting decreases in indices of cortical excitability, and alterations in performance of behavioral tasks. We investigated the effects of cTBS on cortical function via functional connectivity and graph theoretical analysis of EEG data. Thirty-one channel resting-state EEG recordings were obtained before and after 40 s of cTBS stimulation to the left primary motor cortex. Functional connectivity between nodes was assessed in multiple frequency bands using lagged max-covariance, and subsequently thresholded to construct undirected graphs. After cTBS, we find widespread decreases in functional connectivity in the alpha band. There are also simultaneous increases in functional connectivity in the high-beta bands, especially amongst anterior and interhemispheric connections. The analysis of the undirected graphs reveals that interhemispheric and interregional connections are more likely to be modulated after cTBS than local connections. There is also a shift in the topology of network connectivity, with an increase in the clustering coefficient after cTBS in the beta bands, and a decrease in clustering and increase in path length in the alpha band, with the alpha-band connectivity primarily decreased near the site of stimulation. cTBS produces widespread alterations in cortical functional connectivity, with resulting shifts in cortical network topology.
Shafi, Mouhsin M.; Westover, M. Brandon; Oberman, Lindsay; Cash, Sydney S.; Pascual-Leone, Alvaro
Impact of the gyral geometry on the electric field induced by transcranial magnetic stimulation.
The spatial extent of the effects of transcranial magnetic stimulation (TMS) on neural tissue is only coarsely understood. One key problem is the realistic calculation of the electric field induced in the brain, which proves difficult due to the complex gyral folding pattern that results in an inhomogeneous conductivity distribution within the skull. We used the finite element method (FEM) together with a high-resolution volume mesh of the human head to better characterize the field induced in cortical gray matter (GM). The volume mesh was constructed from T1-weighted structural magnetic resonance images to allow for an anatomically accurate modeling of the gyrification pattern. Five tissue types were taken into account, corresponding to skin, skull, cerebrospinal fluid (CSF) including the ventricles as well as cortical gray and white matter. We characterized the effect of the current direction on the electric field distribution in GM. Importantly, the field strength in GM was increased by up to 51% when the induced currents were perpendicular to the local gyrus orientation. This effect was mainly restricted to the gyral crowns and lips, but did not extend into the sulcal walls. As a result, the focality of the fields induced in GM was increased. This enhancement effect might in part underlie the dependency of stimulation thresholds on coil orientation, as commonly observed in TMS motor cortex studies. In contrast to the clear-cut effects of the gyrification pattern on the induced field strength, current directions were predominantly influenced by the CSF-skull boundary. PMID:20682353
Thielscher, Axel; Opitz, Alexander; Windhoff, Mirko
Comparison of current distributions in electroconvulsive therapy and transcranial magnetic stimulation
We compared current density distributions in electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) by numerical calculations. The model consisted of an air region and three types of tissues with different conductivities representing the brain, the skull, and the scalp. In the ECT model, electric currents were applied through electrodes with a voltage of 100 V. In the TMS model, a figure-eight coil (6 cm diameter per coil) was placed on the vertex of the head model. An alternating current with a peak intensity of 3.0 kA and a frequency of 4.2 kHz was applied to the coil. The maximum current densities inside the brain in ECT (bilateral electrode position) and TMS were 234 and 322 A/m2, respectively. The results indicate that magnetic stimulators can generate comparable current densities to ECT. While the skull significantly affected current distributions in ECT, TMS efficiently induced eddy currents in the brain. In addition, TMS is more beneficial than ECT because the localized current distribution reduces the risk of adverse side effects.
Sekino, Masaki; Ueno, Shoogo
A measure of acoustic noise generated from transcranial magnetic stimulation�coils.
The intensity of sound emanating from the discharge of magnetic coils used in repetitive transcranial magnetic stimulation (rTMS) can potentially cause acoustic trauma. Per Occupational Safety and Health Administration (OSHA) standards for safety of noise exposure, hearing protection is recommended beyond restricted levels of noise and time limits. We measured the sound pressure levels (SPLs) from four rTMS coils with the goal of assessing if the acoustic artifact levels are of sufficient amplitude to warrant protection from acoustic trauma per OSHA standards. We studied the SPLs at two frequencies (5�and 10 Hz), three machine outputs (MO) (60, 80 and 100%), and two distances from the coil (5 and 10�cm). We found that the SPLs were louder at closer proximity from the coil and directly dependent on the MO. We also found that in all studied conditions, SPLs were lower than the OSHA permissible thresholds for short (<15 min) acoustic exposure, but at extremes of use, may generate sufficient noise to warrant ear protection with prolonged (>8 h) exposure. PMID:24582370
Dhamne, Sameer C; Kothare, Raveena S; Yu, Camilla; Hsieh, Tsung-Hsun; Anastasio, Elana M; Oberman, Lindsay; Pascual-Leone, Alvaro; Rotenberg, Alexander
Cerebral blood flow identifies responders to transcranial magnetic stimulation in auditory verbal hallucinations
Auditory hallucinations comprise a critical domain of psychopathology in schizophrenia. Repetitive transcranial magnetic stimulation (TMS) has shown promise as an intervention with both positive and negative reports. The aim of this study was to test resting-brain perfusion before treatment as a possible biological marker of response to repetitive TMS. Twenty-four medicated patients underwent resting-brain perfusion magnetic resonance imaging with arterial spin labeling (ASL) before 10 days of repetitive TMS treatment. Response was defined as a reduction in the hallucination change scale of at least 50%. Responders (n=9) were robustly differentiated from nonresponders (n=15) to repetitive TMS by the higher regional cerebral blood flow (CBF) in the left superior temporal gyrus (STG) (P<0.05, corrected) before treatment. Resting-brain perfusion in the left STG predicted the response to repetitive TMS in this study sample, suggesting this parameter as a possible bio-marker of response in patients with schizophrenia and auditory hallucinations. Being noninvasive and relatively easy to use, resting perfusion measurement before treatment might be a clinically relevant way to identify possible responders and nonresponders to repetitive TMS.
Homan, P; Kindler, J; Hauf, M; Hubl, D; Dierks, T
Cerebral blood flow identifies responders to transcranial magnetic stimulation in auditory verbal hallucinations.
Auditory hallucinations comprise a critical domain of psychopathology in schizophrenia. Repetitive transcranial magnetic stimulation (TMS) has shown promise as an intervention with both positive and negative reports. The aim of this study was to test resting-brain perfusion before treatment as a possible biological marker of response to repetitive TMS. Twenty-four medicated patients underwent resting-brain perfusion magnetic resonance imaging with arterial spin labeling (ASL) before 10 days of repetitive TMS treatment. Response was defined as a reduction in the hallucination change scale of at least 50%. Responders (n=9) were robustly differentiated from nonresponders (n=15) to repetitive TMS by the higher regional cerebral blood flow (CBF) in the left superior temporal gyrus (STG) (P<0.05, corrected) before treatment. Resting-brain perfusion in the left STG predicted the response to repetitive TMS in this study sample, suggesting this parameter as a possible bio-marker of response in patients with schizophrenia and auditory hallucinations. Being noninvasive and relatively easy to use, resting perfusion measurement before treatment might be a clinically relevant way to identify possible responders and nonresponders to repetitive TMS. PMID:23168989
Preserved transcallosal inhibition to transcranial magnetic stimulation in nondemented elderly patients with leukoaraiosis.
Structural corpus callosum (CC) changes in patients with leukoaraiosis (LA) are significantly associated with cognitive and motor impairment. The aim of this study is to investigate the transcallosal fibers functioning by means of transcranial magnetic stimulation (TMS) in elderly patients with LA. The resting motor threshold (rMT), the motor-evoked potentials (MEPs), and the controlateral (cSP) and ipsilateral silent periods (iSP) were determined using single-pulse TMS in 15 patients and 15 age-matched controls. The neuropsychological profile and the vascular burden at brain magnetic resonance imaging (MRI) were concomitantly explored. Patients reported abnormal scores at tests evaluating executive control functions. No significant difference was found in TMS measures of intra- and intercortical excitability. No CC lesion was evident at MRI. Transcallosal inhibitory mechanisms to TMS seem to be spared in LA patients, a finding which is in line with neuroimaging features and suggests a functional integrity of the CC despite the ischemic interruption of corticosubcortical loops implicated in cognition and behavior. The observed neurophysiological finding differs from that reported in degenerative dementia, even in the preclinical or early stage. In our group of patients, the pure extent of LA is more related to impairment of frontal lobe abilities rather than functional callosal changes. PMID:23984349
Lanza, Giuseppe; Bella, Rita; Giuffrida, Salvatore; Cantone, Mariagiovanna; Pennisi, Giovanni; Spampinato, Concetto; Giordano, Daniela; Malaguarnera, Giulia; Raggi, Alberto; Pennisi, Manuela
Baseline Brain Metabolism in Resistant Depression and Response to Transcranial Magnetic Stimulation
Neuroimaging studies of patients with treatment-resistant depression (TRD) have reported abnormalities in the frontal and temporal regions. We sought to determine whether metabolism in these regions might be related to response to repetitive transcranial magnetic stimulation (TMS) in patients with TRD. Magnetic resonance images and baseline resting-state cerebral glucose uptake index (gluMI) obtained using 18F-fluorodeoxyglucose positron emission tomography were analyzed in TRD patients who had participated in a double-blind, randomized, sham-controlled trial of prefrontal 10?Hz TMS. Among the patients randomized to active TMS, 17 responders, defined as having 50% depression score decrease, and 14 nonresponders were investigated for prestimulation glucose metabolism and compared with 39 healthy subjects using a voxel-based analysis. In nonresponders relative to responders, gluMI was lower in left lateral orbitofrontal cortex (OFC), and higher in left amygdala and uncinate fasciculus. OFC and amygdala gluMI negatively correlated in nonresponders, positively correlated in responders, and did not correlate in healthy subjects. Relative to healthy subjects, both responders and nonresponders displayed lower gluMI in right dorsolateral prefrontal (DLPFC), right anterior cingulate (ACC), and left ventrolateral prefrontal cortices. Additionally, nonresponders had lower gluMI in left DLPFC, ACC, left and right insula, and higher gluMI in left amygdala and uncus. Hypometabolisms were partly explained by gray matter reductions, whereas hypermetabolisms were unrelated to structural changes. The findings suggest that different patterns of frontal�temporal�limbic abnormalities may distinguish responders and nonresponders to prefrontal magnetic stimulation. Both preserved OFC volume and amygdala metabolism might precondition response to TMS.
Martinot, Marie-Laure Paillere; Martinot, Jean-Luc; Ringuenet, Damien; Galinowski, Andre; Gallarda, Thierry; Bellivier, Frank; Lefaucheur, Jean-Pascal; Lemaitre, Herve; Artiges, Eric
Predictability of saccadic behaviors is modified by transcranial magnetic stimulation over human posterior parietal cortex.
Predictability in the visual environment provides a powerful cue for efficient processing of scenes and objects. Recently, studies have suggested that the directionality and magnitude of saccade curvature can be informative as to how the visual system processes predictive information. The present study investigated the role of the right posterior parietal cortex (rPPC) in shaping saccade curvatures in the context of predictive and non-predictive visual cues. We used an orienting paradigm that incorporated manipulation of target location predictability and delivered transcranial magnetic stimulation (TMS) over rPPC. Participants were presented with either an informative or uninformative cue to upcoming target locations. Our results showed that rPPC TMS generally increased saccade latency and saccade error rates. Intriguingly, rPPC TMS increased curvatures away from the distractor only when the target location was unpredictable and decreased saccadic errors towards the distractor. These effects on curvature and accuracy were not present when the target location was predictable. These results dissociate the strong contingency between saccade latency and saccade curvature and also indicate that rPPC plays an important role in allocating and suppressing attention to distractors when the target demands visual disambiguation. Furthermore, the present study suggests that, like the frontal eye fields, rPPC is critically involved in determining saccade curvature and the generation of saccadic behaviors under conditions of differing target predictability. PMID:21259383
Chao, Chang-Mao; Tseng, Philip; Hsu, Tzu-Yu; Su, Jia-Han; Tzeng, Ovid J L; Hung, Daisy L; Muggleton, Neil G; Juan, Chi-Hung
Safety and Behavioral Effects of High-Frequency Repetitive Transcranial Magnetic Stimulation in Stroke
Background and Purpose Electromagnetic brain stimulation might have value to reduce motor deficits after stroke. Safety and behavioral effects of higher frequencies of repetitive transcranial magnetic stimulation (rTMS) require detailed assessment. Methods Using an active treatment-only, unblinded, 2-center study design, patients with chronic stroke received 20 minutes of 20 Hz rTMS to the ipsilesional primary motor cortex hand area. Patients were assessed before, during the hour after, and 1 week after rTMS. Results The 12 patients were 4.7�4.9 years poststroke (mean�SD) with moderate�severe arm motor deficits. In terms of safety, rTMS was well tolerated and did not cause new symptoms; systolic blood pressure increased from pre- to immediately post-rTMS by 7 mm Hg (P=0.043); and none of the behavioral measures showed a decrement. In terms of behavioral effects, modest improvements were seen, for example, in grip strength, range of motion, and pegboard performance, up to 1 week after rTMS. The strongest predictor of these motor gains was lower patient age. Conclusions A single session of high-frequency rTMS to the motor cortex was safe. These results require verification with addition of a placebo group and thus blinded assessments across a wide spectrum of poststroke deficits and with larger doses of 20 Hz rTMS.
Yozbatiran, Nuray; Alonso-Alonso, Miguel; See, Jill; Demirtas-Tatlidede, Asli; Luu, Daniel; Motiwala, Rehan R.; Pascual-Leone, Alvaro; Cramer, Steven C.
Repetitive transcranial magnetic stimulator with controllable pulse parameters (cTMS).
We describe a novel transcranial magnetic stimulation (TMS) device that uses a circuit topology incorporating two energy-storage capacitors and two insulated-gate bipolar transistors (IGBTs) to generate near-rectangular electric field E-field) pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable-pulse-parameter TMS (cTMS) device can induce E-field pulses with phase widths of 5-200 �s and positive/negative phase amplitude ratio of 1-10. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation by 78-82% and 55-57% and decreases coil heating by 15-33% and 31-41%, respectively. We demonstrate repetitive TMS (rTMS) trains of 3,000 pulses at frequencies up to 50 Hz with E-field pulse amplitude and width variability of less than 1.7% and 1%, respectively. The reduced power consumption and coil heating, and the flexible pulse parameter adjustment offered by cTMS could enhance existing TMS paradigms and could enable novel research and clinical applications with potentially enhanced potency. PMID:21095986
Assessing consciousness in coma and related states using transcranial magnetic stimulation combined with electroencephalography.
Thanks to advances in medical care, an increased number of patients recover from coma. However, some remain in vegetative/unresponsive wakefulness syndrome or in a minimally conscious state. Detection of awareness in severely brain-injured patients is challenging because it relies on behavioral assessments, which can be affected by motor, sensory and cognitive impairments of the patients. Other means of evaluation are needed to improve the accuracy of the diagnosis in this challenging population. We will here review the different altered states of consciousness occurring after severe brain damage, and explain the difficulties associated with behavioral assessment of consciousness. We will then describe a non-invasive technique, transcranial magnetic stimulation combined with high-density electroencephalography (TMS-EEG), which has allowed us to detect the presence or absence of consciousness in different physiological, pathological and pharmacological states. Some potential underlying mechanisms of the loss of consciousness will then be discussed. In conclusion, TMS-EEG is highly promising in identifying markers of consciousness at the individual level and might be of great value for clinicians in the assessment of consciousness. PMID:24393302
Gosseries, O; Thibaut, A; Boly, M; Rosanova, M; Massimini, M; Laureys, S
Phosphene-guided transcranial magnetic stimulation of occipital but not parietal cortex suppresses stimulus visibility.
Transcranial magnetic stimulation (TMS) applied over the occipital lobe approximately 100�ms after the onset of a stimulus decreases its visibility if it appears in the location of the phosphene. Because phosphenes can also be elicited by stimulation of the parietal regions, we asked if the same procedure that is used to reduce visibility of stimuli with occipital TMS will lead to decreased stimulus visibility when TMS is applied to parietal regions. TMS was randomly applied at 0-130�ms after the onset of the stimulus in steps of 10�ms in occipital and parietal regions. Participants responded to the orientation of the line stimulus and rated its visibility. We replicate previous reports of phosphenes from both occipital and parietal TMS. As previously reported, we also observed visual suppression around the classical 100�ms window both in the objective line orientation and subjective visibility responses with occipital TMS. Parietal stimulation, on the other hand, did not consistently reduce stimulus visibility in any time window. PMID:24584900
Tapia, Evelina; Mazzi, Chiara; Savazzi, Silvia; Beck, Diane M
Modulation of preparatory volitional motor cortical activity by paired associative transcranial magnetic stimulation.
Paired associative transcranial magnetic stimulation (PAS) has been shown to induce long-term potentiation (LTP)-like or long-term depression (LTD)-like change in excitability of human primary motor cortex (M1), as probed by motor evoked potential (MEP) amplitude. In contrast, little is known about PAS effects on volitional motor cortical activity. In 10 healthy subjects, movement related cortical potentials (MRCP) were recorded to index volitional motor cortical activity during preparation of simple thumb abduction (prime mover: abductor pollicis brevis, APB) or wrist extension movements (prime mover: extensor carpi radialis, ECR). PAS(LTP) increased, PAS(LTD) decreased, and PAS(control) did not change MEP(APB), while MEP(ECR), not targeted by PAS, remained unchanged in all PAS conditions. PAS(LTP) decreased MRCP negativity during the late Bereitschaftspotential (-500 to 0 ms before movement onset), only in the APB task, and predominantly over central scalp electrodes contralateral to the thumb movements. This effect correlated negatively with the PAS(LTP) induced increase in MEP(APB). PAS(LTD) and PAS(control) did not affect MRCP amplitude. Findings indicate a specific interference of PAS with preparatory volitional motor cortical activity, suggestive of a net result caused by increased M1 excitability and disrupted effective connectivity between premotor areas and M1. PMID:19384889
Lu, Ming-Kuei; Bliem, Barbara; Jung, Patrick; Arai, Noritoshi; Tsai, Chon-Haw; Ziemann, Ulf
The effects of lateral prefrontal transcranial magnetic stimulation on item memory encoding.
Previous neuroimaging research has established that the left ventrolateral prefrontal cortex (VLPFC) is involved in long-term memory (LTM) encoding for individual items. Dorsolateral prefrontal cortex (DLPFC) is implicated less frequently, and one theory that has gained support to explain this discrepancy is that DLPFC is involved in forming item-item relational but not item LTM. Given that neuroimaging results are correlational, complimentary methods such as repetitive transcranial magnetic stimulation (TMS) have been used to test causal hypotheses generated from imaging data. Most TMS studies of LTM encoding have found that disruption of lateral PFC activity impairs subsequent memory. However these studies have lacked methods to precisely localize and directly compare TMS effects from frontal subregions implicated by the neuroimaging literature. Here, we target specific subregions of lateral PFC with TMS to test the prediction from the item/relational framework that temporary disruption of VLPFC during encoding will impair subsequent memory whereas TMS to DLPFC during item encoding will not. Frontal TMS was administered prior to a LTM encoding task in which participants were presented with a list of individual nouns and asked to judge whether each noun was concrete or abstract. After a 40 min delay period, item recognition memory was tested. Results indicate that VLPFC and DLPFC TMS have differential effects on subsequent item memory. VLPFC TMS reliably disrupted subsequent item memory whereas DLPFC TMS led to numerical enhancement in item memory, relative to TMS to a control region. PMID:24316198
Blumenfeld, Robert S; Lee, Taraz G; D'Esposito, Mark
Correlation Networks for Identifying Changes in Brain Connectivity during Epileptiform Discharges and Transcranial Magnetic Stimulation.
The occurrence of epileptiform discharges (ED) in electroencephalographic (EEG) recordings of patients with epilepsy signifies a change in brain dynamics and particularly brain connectivity. Transcranial magnetic stimulation (TMS) has been recently acknowledged as a non-invasive brain stimulation technique that can be used in focal epilepsy for therapeutic purposes. In this case study, it is investigated whether simple time-domain connectivity measures, namely cross-correlation and partial cross-correlation, can detect alterations in the connectivity structure estimated from selected EEG channels before and during ED, as well as how this changes with the application of TMS. The correlation for each channel pair is computed on non-overlapping windows of 1 s duration forming weighted networks. Further, binary networks are derived by thresholding or statistical significance tests (parametric and randomization tests). The information for the binary networks is summarized by statistical network measures, such as the average degree and the average path length. Alterations of brain connectivity before, during and after ED with or without TMS are identified by statistical analysis of the network measures at each state. PMID:25025550
Siggiridou, Elsa; Kugiumtzis, Dimitris; Kimiskidis, Vasilios K
Fast multigrid-based computation of the induced electric field for transcranial magnetic stimulation
In transcranial magnetic stimulation (TMS), the distribution of the induced electric field, and the affected brain areas, depends on the position of the stimulation coil and the individual geometry of the head and brain. The distribution of the induced electric field in realistic anatomies can be modelled using computational methods. However, existing computational methods for accurately determining the induced electric field in realistic anatomical models have suffered from long computation times, typically in the range of tens of minutes or longer. This paper presents a matrix-free implementation of the finite-element method with a geometric multigrid method that can potentially reduce the computation time to several seconds or less even when using an ordinary computer. The performance of the method is studied by computing the induced electric field in two anatomically realistic models. An idealized two-loop coil is used as the stimulating coil. Multiple computational grid resolutions ranging from 2 to 0.25 mm are used. The results show that, for macroscopic modelling of the electric field in an anatomically realistic model, computational grid resolutions of 1 mm or 2 mm appear to provide good numerical accuracy compared to higher resolutions. The multigrid iteration typically converges in less than ten iterations independent of the grid resolution. Even without parallelization, each iteration takes about 1.0 s or 0.1 s for the 1 and 2 mm resolutions, respectively. This suggests that calculating the electric field with sufficient accuracy in real time is feasible.
Laakso, Ilkka; Hirata, Akimasa
In-session seizures during low-frequency repetitive transcranial magnetic stimulation in patients with epilepsy.
Low-frequency repetitive transcranial magnetic stimulation (rTMS) is emerging as a therapeutic tool for patients with intractable epilepsy. Although seizures during treatment have been reported as adverse events in some patients, the nature and severity of seizures that may be provoked by low-frequency rTMS in patients with epilepsy have not been extensively studied. Accordingly, this article documents seizures in patients (n=5) with intractable epilepsy and average seizure frequency greater than one per day who underwent 1-Hz rTMS for seizure suppression. We report three observations in the present case series: (1) in each instance the in-session seizure was typical in semiology to the patient's habitual seizures, (2) the duration of each documented seizure was either the same as or shorter than the patients' baseline seizures, and (3) the overall neurological outcome on follow-up was not affected by the in-session seizures. More data will be required for valid conclusions with respect to safety and tolerability of low-frequency rTMS in patients with epilepsy, but it is noteworthy from our perspective that seizures during rTMS in this series were similar to the patients' habitual seizures, occurred in patients with epilepsy with baseline seizure frequency exceeding one per day, and did not correlate with a poor neurological outcome or with absence of clinical response to rTMS. PMID:19747883
Rotenberg, Alexander; Bae, Erica Hyunji; Muller, Paul A; Riviello, James J; Bourgeois, Blaise F; Blum, Andrew S; Pascual-Leone, Alvaro
Transcranial magnetic stimulation modulates the brain's intrinsic activity in a frequency-dependent manner.
Intrinsic activity in the brain is organized into networks. Although constrained by their anatomical connections, functional correlations between nodes of these networks reorganize dynamically. Dynamic organization implies that couplings between network nodes can be reconfigured to support processing demands. To explore such reconfigurations, we combined repetitive transcranial magnetic stimulation (rTMS) and functional connectivity MRI (fcMRI) to modulate cortical activity in one node of the default network, and assessed the effect of this upon functional correlations throughout the network. Two different frequencies of rTMS to the same default network node (the left posterior inferior parietal lobule, lpIPL) induced two topographically distinct changes in functional connectivity. High-frequency rTMS to lpIPL decreased functional correlations between cortical default network nodes, but not between these nodes and the hippocampal formation. In contrast, low frequency rTMS to lpIPL did not alter connectivity between cortical default network nodes, but increased functional correlations between lpIPL and the hippocampal formation. These results suggest that the default network is composed of (at least) two subsystems. More broadly, the finding that two rTMS stimulation regimens to the same default network node have distinct effects reveals that this node is embedded within a network that possesses multiple, functionally distinct relationships among its distributed partners. PMID:22160708
Eldaief, Mark C; Halko, Mark A; Buckner, Randy L; Pascual-Leone, Alvaro
A novel approach for documenting phosphenes induced by transcranial magnetic stimulation.
Stimulation of the human visual cortex produces a transient perception of light, known as a phosphene. Phosphenes are induced by invasive electrical stimulation of the occipital cortex, but also by non-invasive Transcranial Magnetic Stimulation (TMS)(1) of the same cortical regions. The intensity at which a phosphene is induced (phosphene threshold) is a well established measure of visual cortical excitability and is used to study cortico-cortical interactions, functional organization (2), susceptibility to pathology (3,4) and visual processing (5-7). Phosphenes are typically defined by three characteristics: they are observed in the visual hemifield contralateral to stimulation; they are induced when the subject s eyes are open or closed, and their spatial location changes with the direction of gaze (2). Various methods have been used to document phosphenes, but a standardized methodology is lacking. We demonstrate a reliable procedure to obtain phosphene threshold values and introduce a novel system for the documentation and analysis of phosphenes. We developed the Laser Tracking and Painting system (LTaP), a low cost, easily built and operated system that records the location and size of perceived phosphenes in real-time. The LTaP system provides a stable and customizable environment for quantification and analysis of phosphenes. PMID:20360672
Elkin-Frankston, Seth; Fried, Peter J; Pascual-Leone, Alvaro; Rushmore, R J; Valero-Cabr, Antoni
The role of the parietal lobe in visual extinction studied with transcranial magnetic stimulation.
Interhemispheric competition between homologous areas in the human brain is believed to be involved in a wide variety of human behaviors from motor activity to visual perception and particularly attention. For example, patients with lesions in the posterior parietal cortex are unable to selectively track objects in the contralesional side of visual space when targets are simultaneously present in the ipsilesional visual field, a form of visual extinction. Visual extinction may arise due to an imbalance in the normal interhemispheric competition. To directly assess the issue of reciprocal inhibition, we used fMRI to localize those brain regions active during attention-based visual tracking and then applied low-frequency repetitive transcranial magnetic stimulation over identified areas in the left and right intraparietal sulcus to asses the behavioral effects on visual tracking. We induced a severe impairment in visual tracking that was selective for conditions of simultaneous tracking in both visual fields. Our data show that the parietal lobe is essential for visual tracking and that the two hemispheres compete for attentional resources during tracking. Our results provide a neuronal basis for visual extinction in patients with parietal lobe damage. PMID:18855545
Battelli, Lorella; Alvarez, George A; Carlson, Thomas; Pascual-Leone, Alvaro
Corticospinal Facilitation during Observation of Graspable Objects: A Transcranial Magnetic Stimulation Study
In 1979, Gibson first advanced the idea that the sight of graspable objects automatically activates in the observer the repertoire of actions necessary to interact with them, even in the absence of any intention to act (�affordance effect�). The neurophysiological substrate of this effect was later identified in a class of bimodal neurons, the so-called "canonical" neurons, located within monkey premotor cortex. In humans, even if different behavioral studies supported the existence of affordance effect, neurophysiological investigations exploring its neural substrates showed contradictory results. Here, by means of Transcranial Magnetic Stimulation (TMS), we explored the time-course of the �affordance effect� elicited by the observation of everyday-life graspable objects on motor cortex of resting observers. We recorded motor evoked potentials (MEP) from three intrinsic hand muscles (two "synergic" for grasping, OP and FDI and one "neutral", ADM). We found that objects� vision determined an increased excitability at 120 milliseconds after their presentation. Moreover, this modulation was proved to be specific to the cortical representations of synergic muscles. From an evolutionary perspective, this timing perfectly fits with a fast recruitment of the motor system aimed at rapidly and accurately choosing the appropriate motor plans in a competitive environment filled with different opportunities.
Canto, Rosario; Brunelli, Nicola; Allione, Luisa; Andreasi, Nico Golfre; Desantis, Marianna; Marzoli, Daniele; Fadiga, Luciano
In-session seizures during low-frequency repetitive transcranial magnetic stimulation in patients with epilepsy
Low-frequency repetitive transcranial magnetic stimulation (rTMS) is emerging as a therapeutic tool for patients with intractable epilepsy. Although seizures during treatment have been reported as adverse events in some patients, the nature and severity of seizures that may be provoked by low-frequency rTMS in patients with epilepsy have not been extensively studied. Accordingly, this article documents seizures in patients (n = 5) with intractable epilepsy and average seizure frequency greater than one per day who underwent 1-Hz rTMS for seizure suppression. We report three observations in the present case series: (1) in each instance the in-session seizure was typical in semiology to the patient�s habitual seizures, (2) the duration of each documented seizure was either the same as or shorter than the patients� baseline seizures, and (3) the overall neurological outcome on follow-up was not affected by the in-session seizures. More data will be required for valid conclusions with respect to safety and tolerability of low-frequency rTMS in patients with epilepsy, but it is noteworthy from our perspective that seizures during rTMS in this series were similar to the patients� habitual seizures, occurred in patients with epilepsy with baseline seizure frequency exceeding one per day, and did not correlate with a poor neurological outcome or with absence of clinical response to rTMS.
Rotenberg, Alexander; Bae, Erica Hyunji; Muller, Paul A.; Riviello, James J.; Bourgeois, Blaise F.; Blum, Andrew S.; Pascual-Leone, Alvaro
Utility of transcranial magnetic stimulation in delineating amyotrophic lateral sclerosis pathophysiology.
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder of the motor neurons in the motor cortex, brainstem, and spinal cord. The clinical phenotype of ALS is underscored by a combination of upper and lower motor neuron dysfunction. Although this phenotype was observed over 100 years ago, the site of ALS onset and the pathophysiological mechanisms underlying the development of motor neuron degeneration remain to be elucidated. Transcranial magnetic stimulation (TMS) enables noninvasive assessment of the functional integrity of the motor cortex and its corticomotoneuronal projections. To date, TMS studies have established cortical dysfunction in ALS, with cortical hyperexcitability being an early feature in sporadic forms of ALS and preceding the clinical onset of familial ALS. Taken together, a central origin of ALS is supported by TMS studies, with an anterograde dying-forward mechanism implicated in ALS pathogenesis. Of further relevance, TMS techniques reliably distinguish ALS from mimic disorders, despite a compatible peripheral disease burden, thereby suggesting a potential diagnostic utility of TMS in ALS. This chapter reviews the mechanisms underlying the generation of TMS parameters utilized in assessment of cortical excitability, the contribution of TMS in enhancing the understanding of ALS pathophysiology, and the potential diagnostic utility of TMS techniques in ALS. PMID:24112924
Vucic, Steve; Kiernan, Matthew C
Potentiation of quantitative electroencephalograms following prefrontal repetitive transcranial magnetic stimulation in patients with major depression.
The long-lasting effects of repetitive transcranial magnetic stimulation (rTMS) on electroencephalogram (EEG) activity are not clear. We aimed to investigate the cumulative rTMS effects on EEG and clinical outcomes in patients with major depression. Twenty-five patients with medication-resistant depression underwent 10 daily rTMS sessions over the left dorsolateral prefrontal cortex. We measured resting EEG and spectrum-power before and after the rTMS course. Clinical efficacy was evaluated with the Hamilton's Depression Rating Scale (HAM-D) and Wisconsin Card Sorting Test (WCST). In an ANOVA model, including all prefrontal electrodes, post hoc analyses revealed significant time effects on the theta (F1,24 = 7.89, P = 0.010; +43%), delta (F1,24 = 6.58, P = 0.017; +26%), and alpha (F1,24 = 4.64, P = 0.042; 31%) bands without site specificity. Clinical correlations were observed between F4 alpha power increases and improvements in HAM-D retardation, F3 alpha power increases and improvements of the absolute changes in perseveration and error number on the WCST, and C3 and C4 theta power increases and improvements of the percent change in perseveration and error number on the WCST following rTMS. Consecutive prefrontal rTMS could induce long-lasting EEG potentiations beyond the aftereffects, resulting in improved cognitive and depressive symptoms. PMID:23827366
Noda, Yoshihiro; Nakamura, Motoaki; Saeki, Takashi; Inoue, Misa; Iwanari, Hideo; Kasai, Kiyoto
The precise adjustment of coil location for transcranial magnetic stimulation during dynamic motion.
Transcranial magnetic stimulation (TMS) to the cerebral cortex is a major in vitro technique that is used in the field of neurophysiology. The magnitude of the motor-evoked potentials (MEP) that are elicited by TMS to the primary motor cortex reflect the excitability of the corticospinal pathway. MEPs are very sensitive to the scalp location of the stimulus coil, especially when corticospinal excitability is recorded during walking or other dynamic motions. In this study, we created a coil navigational system that consisted of three-dimensional motion analysis cameras, rigid bodies on the head and coil, and programming software. In order to evaluate the feasibility of the use of our system, pseudo TMS was applied during treadmill walking with or without the navigational system. As a result, we found that the variances due to coil location and/or distance from the target site were reduced with our system. This technique enabled us to realize high precision and accuracy in coil placement, even during dynamic motion. PMID:24110503
Kitamura, Taku; Yaeshima, Katsutoshi; Yamamoto, Shin-Ichiro; Kawashima, Noritaka
Biophysical determinants of transcranial magnetic stimulation: effects of excitability and depth of targeted area.
Safe and effective transcranial magnetic stimulation (TMS) requires accurate intensity calibration. Output is typically calibrated to individual motor cortex excitability and applied to nonmotor brain areas, assuming that it captures a site nonspecific factor of excitability. We tested this assumption by correlating the effect of TMS at motor and visual cortex. In 30 participants, we measured motor threshold (MT) and phosphene threshold (PT) at the scalp surface and at coil-scalp distances of 3.17, 5.63, and 9.03 mm. We also modeled the effect of TMS in a simple head model to test the effect of distance. Four independent tests confirmed a significant correlation between PT and MT. We also found similar effects of distance in motor and visual areas, which did not correlate across participants. Computational modeling suggests that the relationship between the effect of distance and the induced electric field is effectively linear within the range of distances that have been explored empirically. We conclude that MT-guided calibration is valid for nonmotor brain areas if coil-cortex distance is taken into account. For standard figure-of-eight TMS coils connected to biphasic stimulators, the effect of cortical distance should be adjusted using a general correction factor of 2.7% stimulator output per millimeter. PMID:23114213
Stokes, Mark G; Barker, Anthony T; Dervinis, Martynas; Verbruggen, Frederick; Maizey, Leah; Adams, Rachel C; Chambers, Christopher D
Fast multigrid-based computation of the induced electric field for transcranial magnetic stimulation.
In transcranial magnetic stimulation (TMS), the distribution of the induced electric field, and the affected brain areas, depends on the position of the stimulation coil and the individual geometry of the head and brain. The distribution of the induced electric field in realistic anatomies can be modelled using computational methods. However, existing computational methods for accurately determining the induced electric field in realistic anatomical models have suffered from long computation times, typically in the range of tens of minutes or longer. This paper presents a matrix-free implementation of the finite-element method with a geometric multigrid method that can potentially reduce the computation time to several seconds or less even when using an ordinary computer. The performance of the method is studied by computing the induced electric field in two anatomically realistic models. An idealized two-loop coil is used as the stimulating coil. Multiple computational grid resolutions ranging from 2 to 0.25�mm are used. The results show that, for macroscopic modelling of the electric field in an anatomically realistic model, computational grid resolutions of 1�mm or 2�mm appear to provide good numerical accuracy compared to higher resolutions. The multigrid iteration typically converges in less than ten iterations independent of the grid resolution. Even without parallelization, each iteration takes about 1.0�s or 0.1�s for the 1 and 2�mm resolutions, respectively. This suggests that calculating the electric field with sufficient accuracy in real time is feasible. PMID:23128377
Transcranial magnetic stimulation in different current directions activates separate cortical circuits.
Transcranial magnetic stimulation (TMS) to the primary motor cortex (M1) produces a series of corticospinal descending waves, with a direct (D) wave followed by several indirect (I) waves. TMS inducing posterior-anterior (PA) current in the brain predominantly recruits the early I1-wave, whereas anterior-posterior (AP) directed current preferentially recruits the late I3-wave. However, it is not known whether I-waves elicited by different current directions are mediated by the same neuronal populations. We studied the neuronal mechanisms mediating I-waves by examining the influence of short-latency afferent inhibition (SAI) on various I-waves. SAI was tested with electrical median nerve stimulation at the wrist followed by TMS to the contralateral M1 at different current directions. Surface electromyograms and single motor units were recorded from the first dorsal interosseous muscle. SAI was weaker for the AP compared with that for the PA current direction. With increasing median nerve stimulation intensities, SAI increased for the PA direction but showed a U-shaped relationship for the AP direction. SAI produced more inhibition of late I-waves generated by PA than those generated by AP current direction. We conclude that late I-waves generated by PA and AP current directions are mediated by different neuronal mechanisms. PMID:21148098
Ni, Zhen; Charab, Samer; Gunraj, Carolyn; Nelson, Aimee J; Udupa, Kaviraja; Yeh, I-Jin; Chen, Robert
Disruptions to human speed perception induced by motion adaptation and transcranial magnetic stimulation.
To investigate the underlying nature of the effects of transcranial magnetic stimulation (TMS) on speed perception, we applied repetitive TMS (rTMS) to human V5/MT+ following adaptation to either fast- (20 deg/s) or slow (4 deg/s)-moving grating stimuli. The adapting stimuli induced changes in the perceived speed of a standard reference stimulus moving at 10 deg/s. In the absence of rTMS, adaptation to the slower stimulus led to an increase in perceived speed of the reference, whilst adaptation to the faster stimulus produced a reduction in perceived speed. These induced changes in speed perception can be modelled by a ratio-taking operation of the outputs of two temporally tuned mechanisms that decay exponentially over time. When rTMS was applied to V5/MT+ following adaptation, the perceived speed of the reference stimulus was reduced, irrespective of whether adaptation had been to the faster- or slower-moving stimulus. The fact that rTMS after adaptation always reduces perceived speed, independent of which temporal mechanism has undergone adaptation, suggests that rTMS does not selectively facilitate activity of adapted neurons but instead leads to suppression of neural function. The results highlight the fact that potentially different effects are generated by TMS on adapted neuronal populations depending upon whether or not they are responding to visual stimuli. PMID:19912329
Burton, M P; McKeefry, D J; Barrett, B T; Vakrou, C; Morland, A B
Amodal semantic representations depend on both anterior temporal lobes: evidence from repetitive transcranial magnetic stimulation.
The key question of how the brain codes the meaning of words and pictures is the focus of vigorous debate. Is there a "semantic hub" in the temporal poles where these different inputs converge to form amodal conceptual representations? Alternatively, are there distinct neural circuits that underpin our comprehension of pictures and words? Understanding words might be primarily left-lateralised, linked to other language areas, while semantic representation of pictures may be more bilateral. To elucidate this debate, we used offline, low-frequency, repetitive transcranial magnetic stimulation (rTMS) to disrupt neural processing temporarily in the left or right temporal poles. During the induced refractory period, participants made judgements of semantic association for verbal and pictorial stimuli. The efficiency of semantic processing was reduced by rTMS, yet a perceptual task of comparable difficulty was unaffected. rTMS applied to the left or right temporal poles disrupted semantic processing for words and pictures to the same degree, while rTMS delivered at a control site had no impact. The results confirm that both temporal poles form a critical substrate within the neural network that supports conceptual knowledge, regardless of modality. PMID:20038436
Pobric, Gorana; Jefferies, Elizabeth; Ralph, Matthew A Lambon
Optimization of the transcranial magnetic stimulation protocol by defining a reliable estimate for corticospinal excitability.
The goal of this study was to optimize the transcranial magnetic stimulation (TMS) protocol for acquiring a reliable estimate of corticospinal excitability (CSE) using single-pulse TMS. Moreover, the minimal number of stimuli required to obtain a reliable estimate of CSE was investigated. In addition, the effect of two frequently used stimulation intensities [110% relative to the resting motor threshold (rMT) and 120% rMT] and gender was evaluated. Thirty-six healthy young subjects (18 males and 18 females) participated in a double-blind crossover procedure. They received 2 blocks of 40 consecutive TMS stimuli at either 110% rMT or 120% rMT in a randomized order. Based upon our data, we advise that at least 30 consecutive stimuli are required to obtain the most reliable estimate for CSE. Stimulation intensity and gender had no significant influence on CSE estimation. In addition, our results revealed that for subjects with a higher rMT, fewer consecutive stimuli were required to reach a stable estimate of CSE. The current findings can be used to optimize the design of similar TMS experiments. PMID:24475111
Cuypers, Koen; Thijs, Herbert; Meesen, Raf L J
Suppression of vibrotactile discrimination by transcranial magnetic stimulation of primary somatosensory cortex.
A number of human and animal studies have reported a differential representation of the frequency of vibrotactile stimuli in the somatosensory cortices: neurons in the primary somatosensory cortex (SI) are predominantly responsive to lower frequencies of tactile vibration, and those in the secondary somatosensory cortex (SII) are predominantly responsive to higher frequencies. We employed transcranial magnetic stimulation (TMS) over SI in human subjects to investigate the extent to which the inactivation of SI disrupted the discrimination of vibrotactile stimulation at frequencies that give rise to the tactile sensations of flutter (30 Hz) and vibration (200 Hz). Frequency discrimination around the 30-Hz standard following application of TMS to SI was reduced in seven of the eight subjects, and around the 200-Hz standard was reduced in all eight subjects. The average change in discrimination following TMS was about 20% for both low and high frequencies of vibrotactile stimulation. These data suggest that disruption of SI: (1) has a direct effect on the discrimination of both low and high frequencies of vibrotactile stimuli, consistent with a serial model of processing, or (2) has a direct effect on low-frequency vibrotactile stimuli and an indirect effect on the processing of high-frequency vibrotactile stimuli by SII via cortico-cortical connections between the two regions. PMID:17714193
Morley, J W; Vickery, R M; Stuart, M; Turman, A B
Functional neuroimaging of the baboon during concurrent image-guided transcranial magnetic stimulation
Transcranial magnetic stimulation (TMS) has well-established applications in basic neuroscience and promising applications in neurological and psychiatric disorders. However the underlying mechanisms of TMS-induced alterations in brain function are not well understood. As a result, treatment design parameters are determined ad hoc and not informed by any coherent theory or model. Once the mechanisms underlying TMS�s modulatory effects on brain systems are better understood and modeled, TMS�s potential as a therapeutic and/or investigative tool will be more readily explored and exploited. An animal model is better suited to study different TMS variables, therefore we developed a baboon model to facilitate testing of some of the current theoretical models of TMS interactions with brain regions. We have demonstrated the feasibility of this approach by successfully imaging cerebral blood flow (CBF) changes with H215O positron emission tomography imaging during high-frequency, suprathreshold repetitive TMS in the primary motor cortex of five healthy, adult baboons.
Salinas, Felipe S.; Szabo, C. Akos; Zhang, Wei; Jones, Lisa; Leland, M. Michelle; Wey, Hsiao-Ying; Duong, Timothy Q.; Fox, Peter T.; Narayana, Shalini
Transcranial magnetic stimulation of medial prefrontal cortex modulates face expressions processing in a priming task.
The medial prefrontal cortex (mPFC) and the right somatosensory cortex (rSC) are known to be involved in emotion processing and face expression recognition, although the possibility of segregated circuits for specific emotions in these regions remains unclear. To investigate this issue, we used transcranial magnetic stimulation (TMS) together with a priming paradigm to modulate the activation state of the mPFC and the rSC during emotional expressions discrimination. This novel paradigm allows analyzing how TMS interacts with the ongoing activity of different neuronal populations following prime processing. Participants were asked to discriminate between angry and happy faces that were preceded by a congruent prime (a word expressing the same emotion), an incongruent prime (a word expressing the opposite emotion) or a neutral prime. In TMS trials, a single pulse was delivered over the mPFC, rSC or Vertex (control site) between prime and target presentation. TMS applied over the mPFC significantly affected the priming effect, by selectively increasing response latencies in congruent trials. This indicates that the mPFC contains different neural representations for angry and happy expressions. TMS over rSC did not significantly affect the priming effect, suggesting that rSC is not involved in processing verbal emotional stimuli. PMID:21281653
Mattavelli, G; Cattaneo, Z; Papagno, C
Reduction of Spasticity With Repetitive Transcranial Magnetic Stimulation in Patients With Spinal Cord Injury
Objective Spasticity with increased tone and spasms is frequent in patients after spinal cord injury (SCI). Damage to descending corticospinal pathways that normally exert spinal segmental control is thought to play an important causal role in spasticity. The authors examined whether the modulation of excitability of the primary motor cortex with high-frequency repetitive transcranial magnetic stimulation (rTMS) could modify lower limb spasticity in patients with incomplete SCI. Methods Patients were assessed by the Modified Ashworth Scale, Visual Analogue Scale, and the Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET) and neurophysiologically with measures of corticospinal and segmental excitability by the Hmax/Mmax, T reflex, and withdrawal reflex. Fifteen patients received 5 days of daily sessions of active (n = 14) or sham (n = 7) rTMS to the leg motor area (20 trains of 40 pulses at 20 Hz and an intensity of 90% of resting motor threshold for the biceps brachii muscle). Result A significant clinical improvement in lower limb spasticity was observed in patients following active rTMS but not after sham stimulation. This improvement lasted for at least 1 week following the intervention. Neurophysiological studies did not change. Conclusions High-frequency rTMS over the leg motor area can improve aspects of spasticity in patients with incomplete SCI.
Kumru, Hatice; Murillo, Narda; Samso, Joan Vidal; Valls-Sole, Josep; Edwards, Dylan; Pelayo, Raul; Valero-Cabre, Antoni; Tormos, Josep Maria; Pascual-Leone, Alvaro
Safety of Theta Burst Transcranial Magnetic Stimulation: A systematic review of the literature
Theta Burst Stimulation (TBS) protocols have recently emerged as a method to transiently alter cortical excitability in the human brain through repetitive transcranial magnetic stimulation (rTMS). TBS involves applying short trains of stimuli at high frequency repeated at intervals of 200ms. Because rTMS is known to carry a risk of seizures, safety guidelines have been established. TBS has the theoretical potential of conferring an even higher risk of seizure than other rTMS protocols because it delivers high frequency bursts. In light of the recent report of a seizure induced by TBS, the safety of this new protocol deserves consideration. We performed an English language literature search, and reviewed all studies published from May 2004-December 2009 in which TBS was applied. The adverse events were documented and crude risk was calculated. The majority of adverse events attributed to TBS were mild and occurred in 5% of subjects. Based on this review, TBS appears to be a safe and efficacious technique. However, given its novelty, it should be applied with caution. Additionally, this review highlights the need for rigorous documentation of adverse events associated with TBS, as well as intensity dosing studies to assess the seizure risk associated with various stimulation parameters (e.g. frequency, intensity, location).
Two means of suppressing visual awareness: a direct comparison of visual masking and transcranial magnetic stimulation.
Visual masking and visual suppression by transcranial magnetic stimulation (TMS) are both widely utilized in cognitive neuroscience to investigate a wide range of processes. However, the neural processes affected by visual masking and TMS remain unclear. We compared para- and metacontrast masking with TMS-induced suppression of visibility in a within-subjects design where participants were asked to detect and rate the visibility of a stimulus. TMS pulses applied 75-109 msec after the onset of the visual stimulus reduced the subjective visibility of the target. Even when the TMS pulses completely eliminated the conscious perception of the target, unconscious location detection was possible. The visual masking condition yielded similar results: metacontrast did not eliminate unconscious location detection even when the target was reported not seen at all. As the first target-related signals were likely to reach the visual cortex before TMS pulses started to modulate target visibility, we suggest that TMS and metacontrast masking affected neural signals subsequent to the target's transient onset-response. This implies that a preserved onset-response is sufficient for unconscious processing of stimulus attributes, but not for conscious perception. PMID:21232737
Railo, Henry; Koivisto, Mika
Altered excitability of the motor cortex after minor head injury revealed by transcranial magnetic stimulation.
This study attempts to find out whether the motor evoked potential (MEP) elicited by single pulse and slow-rate (1 Hz) repetitive transcranial magnetic stimulation (TMS) can disclose concealed subclinical impairments in the cerebral motor system of patients with minor head injury. The motor response to single pulse TMS (STMS) of the patient group was characterized by significantly higher threshold compared with that of the control group. The central motor conduction time, as well as the peripheral conduction time were normal in all patients pointing to cortical impairment. Two main patterns of MEP changes in response to repetitive TMS (RTMS) were observed in the patient group. A.--progressive decrease of the MEP amplitude throughout the stimulation session to a near complete abolition. B.--irregularity of the amplitude and the waveform of the MEP in a chaotic form. The MEP latency remained stable during the whole stimulation session. The MEP abnormalities recovered gradually over the period of a few months. The higher threshold of the motor response to STMS and the abnormal patterns of the MEP to RTMS seem to reflect transient impairment of cortical excitability or "cortical fatigue" in patients who sustained minor head injures. Further study is needed to evaluated the extent and the pathophysiological mechanisms of the central nervous system fatigue phenomenon following head injury. PMID:9728247
Chistyakov, A V; Soustiel, J F; Hafner, H; Elron, M; Feinsod, M
Transcranial magnetic stimulation disrupts the perception and embodiment of facial expressions.
Theories of embodied cognition propose that recognizing facial expressions requires visual processing followed by simulation of the somatovisceral responses associated with the perceived expression. To test this proposal, we targeted the right occipital face area (rOFA) and the face region of right somatosensory cortex (rSC) with repetitive transcranial magnetic stimulation (rTMS) while participants discriminated facial expressions. rTMS selectively impaired discrimination of facial expressions at both sites but had no effect on a matched face identity task. Site specificity within the rSC was demonstrated by targeting rTMS at the face and finger regions while participants performed the expression discrimination task. rTMS targeted at the face region impaired task performance relative to rTMS targeted at the finger region. To establish the temporal course of visual and somatosensory contributions to expression processing, double-pulse TMS was delivered at different times to rOFA and rSC during expression discrimination. Accuracy dropped when pulses were delivered at 60-100 ms at rOFA and at 100-140 and 130-170 ms at rSC. These sequential impairments at rOFA and rSC support embodied accounts of expression recognition as well as hierarchical models of face processing. The results also demonstrate that nonvisual cortical areas contribute during early stages of expression processing. PMID:18768686
Pitcher, David; Garrido, L�cia; Walsh, Vincent; Duchaine, Bradley C
A survey of patient acceptability of repetitive transcranial magnetic stimulation (TMS) during pregnancy
Objective Given the data that depression is common during pregnancy and that pregnant women prefer non-medication treatment options, we hypothesize repetitive transcranial magnetic stimulation (TMS) may be a treatment option. Given the novelty of TMS, we sought to assess whether patient acceptability would be a barrier to enrolling pregnant women in TMS studies. Methods In Study 1, 500 pregnant women were surveyed in an outpatient, urban obstetrics clinic using the Edinburgh Depression Rating Scale (EPDS) and a treatment acceptability survey. In Study 2, 51 women were surveyed with the EPDS and acceptability survey using an informational video to increase participant knowledge about TMS. Results Approximately 25% of participants had an EPDS score of ?12 in both studies. Psychotherapy was identified as the most acceptable treatment option. TMS was considered an unacceptable treatment option to virtually all women before the informational video. After the video, 15.7% considered TMS an acceptable treatment option. Conclusion Psychotherapy is the most acceptable treatment option for depression to pregnant women. Increasing participant knowledge about TMS increased its acceptability significantly. Large-scale multi-center trials are needed for confirmation of these results.
Kim, Deborah R.; Sockol, Laura; Barber, Jacques P.; Moseley, Marian; Lamprou, Lisa; Rickels, Karl; O'Reardon, John P.; Epperson, C. Neill
Theta-burst repetitive transcranial magnetic stimulation suppresses specific excitatory circuits in the human motor cortex
In four conscious patients who had electrodes implanted in the cervical epidural space for the control of pain, we recorded corticospinal volleys evoked by single-pulse transcranial magnetic stimulation (TMS) over the motor cortex before and after a 20 s period of continuous theta-burst stimulation (cTBS). It has previously been reported that this form of repetitive TMS reduces the amplitude of motor-evoked potentials (MEPs), with the maximum effect occurring at 5�10 min after the end of stimulation. The present results show that cTBS preferentially decreases the amplitude of the corticospinal I1 wave, with approximately the same time course. This is consistent with a cortical origin of the effect on the MEP. However, other protocols that lead to MEP suppression, such as short-interval intracortical inhibition, are characterized by reduced excitability of late I waves (particularly I3), suggesting that cTBS suppresses MEPs through different mechanisms, such as long-term depression in excitatory synaptic connections.
Di Lazzaro, V; Pilato, F; Saturno, E; Oliviero, A; Dileone, M; Mazzone, P; Insola, A; Tonali, PA; Ranieri, F; Huang, YZ; Rothwell, JC
What have We Learned from "Perturbing" the Human Cortical Motor System with Transcranial Magnetic Stimulation?
The purpose of this paper is twofold. First, we will review different approaches that one can use with transcranial magnetic stimulation (TMS) to study both its effects on motor behavior and on neural connections in the human brain. Second, we will present evidence obtained in TMS-based studies showing that the dorsal premotor area (PMd), the ventral premotor area (PMv), the supplementary motor area (SMA), and the pre-supplementary motor area (pre-SMA) each have different roles to play in motor behavior. We highlight the importance of the PMd in response selection based on arbitrary cues and in the control of arm movements, the PMv in grasping and in the discrimination of bodily actions, the SMA in movement sequencing and in bimanual coordination, and the pre-SMA in cognitive control. We will also discuss ways in which TMS can be used to chart �true� cerebral reorganization in clinical populations and how TMS might be used as a therapeutic tool to facilitate motor recovery after stroke. We will end our review by discussing some of the methodological challenges and future directions for using this tool in basic and clinical neuroscience.
Chouinard, Philippe A.; Paus, Tomas
Motor hand recovery after stroke. Prognostic yield of early transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) was performed in 20 patients within the first days after stroke. Motor evoked potentials (MEPs) were bilaterally recorded over thenar eminence muscles, and central motor conduction time (CMCT), amplitude of the MEPs (A%M) and threshold intensity compared between both sides. Six months later the patients were reexamined. Within the first days after stroke the obtention of MEPs at rest or during voluntary muscle activation have a favorable prognostic value. All patients with early response by TMS reached a good motor function in the following months. The follow-up showed that the electrophysiological improvement was closely related to clinical recovery of the hand function. However, even in cases with a good recovery, the CMCT and, mainly, the A%M, may be significantly different related to those in normal hand. TMS may be an early and valuable prognostic indicator of hand function recovery after stroke, and their prognostic yield is higher than clinical evaluation and CT study. TMS is a quantifiable method of motor disability and may have practical application in the management and rehabilitation therapy in stroke patients. PMID:10546076
Cruz Mart�nez, A; Tejada, J; D�ez Tejedor, E
Interleaved transcranial magnetic stimulation and fMRI suggests that lamotrigine and valproic acid have different effects on corticolimbic activity
Rationale��Combined transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) can be used to study anticonvulsant\\u000a drugs. A previous study showed that lamotrigine (LTG) inhibited brain activation induced when TMS was applied over motor cortex,\\u000a whereas it increased activation induced by TMS applied over prefrontal cortex.\\u000a \\u000a \\u000a \\u000a \\u000a Objectives��The present double-blind, placebo-controlled, crossover study in 30 healthy subjects again combined TMS
Xingbao Li; Raffaella Ricci; Charles H. Large; Berry Anderson; Ziad Nahas; Daryl E. Bohning; Mark S. George
Effect of Repetitive Transcranial Magnetic Stimulation on Patients with Brain Injury and Dysphagia
Objective To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on recovery of the swallowing function in patients with a brain injury. Method Patients with a brain injury and dysphagia were enrolled. Patients were randomly assigned to sham, and low and high frequency stimulation groups. We performed rTMS at 100% of motor evoked potential (MEP) threshold and a 5 Hz frequency for 10 seconds and then repeated this every minute in the high frequency group. In the low frequency group, magnetic stimulation was conducted at 100% of MEP threshold and a 1 Hz frequency. The sham group was treated using the same parameters as the high frequency group, but the coil was rotated 90� to create a stimulus noise. The treatment period was 2 weeks (5 days per week, 20 minutes per session). We evaluated the Functional Dysphagia Scale (FDS) and the Penetration Aspiration Scale (PAS) with a videofluoroscopic swallowing study before and after rTMS. Results Thirty patients were enrolled, and mean patient age was 68.2 years. FDS and PAS scores improved significantly in the low frequency group after rTMS, and American Speech-Language Hearing Association National Outcomes Measurements System Swallowing Scale scores improved in the sham and low frequency groups. FDS and PAS scores improved significantly in the low frequency group compared to those in the other groups. Conclusion We demonstrated that low frequency rTMS facilitated the recovery of swallowing function in patients with a brain injury, suggesting that rTMS is a useful modality to recover swallowing function.
Kim, Leesuk; Kim, Bo Ryun; Lee, Sook Joung
Tracking post-error adaptation in the motor system by transcranial magnetic stimulation.
The commission of an error triggers cognitive control processes dedicated to error correction and prevention. Post-error adjustments leading to response slowing following an error ("post-error slowing"; PES) might be driven by changes in excitability of the motor regions and the corticospinal tract (CST). The time-course of such excitability modulations of the CST leading to PES is largely unknown. To track these presumed excitability changes after an error, single pulse transcranial magnetic stimulation (TMS) was applied to the motor cortex ipsilateral to the responding hand, while participants were performing an Eriksen flanker task. A robotic arm with a movement compensation system was used to maintain the TMS coil in the correct position during the experiment. Magnetic pulses were delivered over the primary motor cortex ipsilateral to the active hand at different intervals (150, 300, 450 ms) after correct and erroneous responses, and the motor-evoked potentials (MEP) of the first dorsal interosseous muscle (FDI) contralateral to the stimulated hemisphere were recorded. MEP amplitude was increased 450 ms after the error. Two additional experiments showed that this increase was neither associated to the correction of the erroneous responses nor to the characteristics of the motor command. To the extent to which the excitability of the motor cortex ipsi- and contralateral to the response hand are inversely related, these results suggest a decrease in the excitability of the active motor cortex after an erroneous response. This modulation of the activity of the CST serves to prevent further premature and erroneous responses. At a more general level, the study shows the power of the TMS technique for the exploration of the temporal evolution of post-error adjustments within the motor system. PMID:23876325
Amengual, J L; Marco-Pallar�s, J; Richter, L; Oung, S; Schweikard, A; Mohammadi, B; Rodr�guez-Fornells, A; M�nte, T F
Brain topological correlates of motor performance changes after repetitive transcranial magnetic stimulation.
Abstract Repetitive transcranial magnetic stimulation (rTMS) influences the brain temporally beyond the stimulation period and spatially beyond the stimulation site. Application of rTMS over the primary motor cortex (M1) has been shown to lead to plastic changes in interregional connectivity over the motor system as well as alterations in motor performance. With a sequential combination of rTMS over the M1 and functional magnetic resonance imaging (fMRI), we sought changes in the topology of brain networks and specifically the association of brain topological changes with motor performance changes. In a sham-controlled parallel group experimental design, real or sham rTMS was administered to each of the 15 healthy subjects without prior motor-related dysfunctions, over the right M1 at a high frequency of 10?Hz. Before and after the intervention, fMRI data were acquired during a sequential finger motor task using the left, nondominant hand. Changes in the topology of brain networks were assessed in terms of global and local efficiency, which measures the efficiency in transporting information at global and local scales, respectively, provided by graph-theoretical analysis. Greater motor performance changes toward improvements after real rTMS were shown in individuals who exhibited more increases in global efficiency and more decreases in local efficiency. The enhancement of motor performance after rTMS is supposed to be associated with brain topological changes, such that global information exchange is facilitated, while local information exchange is restricted. PMID:24575849
Park, Chang-Hyun; Chang, Won Hyuk; Yoo, Woo-Kyoung; Shin, Yong-Il; Kim, Sung Tae; Kim, Yun-Hee
Solving the orientation specific constraints in transcranial magnetic stimulation by rotating fields.
Transcranial Magnetic Stimulation (TMS) is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS) efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback) and will enable stimulation in brain regions where a preferred axonal orientation does not exist. PMID:24505266
Rotem, Assaf; Neef, Andreas; Neef, Nicole E; Agudelo-Toro, Andres; Rakhmilevitch, David; Paulus, Walter; Moses, Elisha
Testing a Neurobiological Model of Depersonalization Disorder Using Repetitive Transcranial Magnetic Stimulation?
Background Depersonalization disorder (DPD) includes changes in subjective experiencing of self, encompassing emotional numbing. Functional magnetic resonance imaging (fMRI) has pointed to ventrolateral prefrontal cortex (VLPFC) inhibition of insula as a neurocognitive correlate of the disorder. Objective We hypothesized that inhibition to right VLPFC using repetitive transcranial magnetic stimulation (rTMS) would lead to increased arousal and reduced symptoms. Methods Patients with medication-resistant DSM-IV DPD (N�=�17) and controls (N�=�20) were randomized to receive one session of right-sided rTMS to VLPFC or temporo-parietal junction (TPJ). 1Hz rTMS was guided using neuronavigation and delivered for 15�min. Co-primary outcomes were: (a) maximum skin conductance capacity, and (b) reduction in depersonalization symptoms (Cambridge Depersonalisation Scale (CDS) [state version]). Secondary outcomes included spontaneous fluctuations (SFs) and event-related skin conductance responses. Results In patients with DPD, rTMS to VLPFC led to increased electrodermal capacity, namely maximum skin conductance deflections. Patients but not controls also showed increased SFs post rTMS. Patients who had either VLPFC or TPJ rTMS showed a similar significant reduction in symptoms. Event-related electrodermal activity did not change. Conclusions A single session of right-sided rTMS to VLPFC (but not TPJ) significantly increased physiological arousal capacity supporting our model regarding the relevance of increased VLPFC activity to emotional numbing in DPD. rTMS to both sites led to reduced depersonalization scores but since this was independent of physiological arousal, this may be a non-specific effect. TMS is a potential therapeutic option for DPD; modulation of VLPFC, if replicated, is a plausible mechanism.
Jay, Emma-Louise; Sierra, Mauricio; Van den Eynde, Frederique; Rothwell, John C.; David, Anthony S.
Extracting Visual Evoked Potentials from EEG Data Recorded During fMRI-guided Transcranial Magnetic Stimulation.
Transcranial Magnetic Stimulation (TMS) is an effective method for establishing a causal link between a cortical area and cognitive/neurophysiological effects. Specifically, by creating a transient interference with the normal activity of a target region and measuring changes in an electrophysiological signal, we can establish a causal link between the stimulated brain area or network and the electrophysiological signal that we record. If target brain areas are functionally defined with prior fMRI scan, TMS could be used to link the fMRI activations with evoked potentials recorded. However, conducting such experiments presents significant technical challenges given the high amplitude artifacts introduced into the EEG signal by the magnetic pulse, and the difficulty to successfully target areas that were functionally defined by fMRI. Here we describe a methodology for combining these three common tools: TMS, EEG, and fMRI. We explain how to guide the stimulator's coil to the desired target area using anatomical or functional MRI data, how to record EEG during concurrent TMS, how to design an ERP study suitable for EEG-TMS combination and how to extract reliable ERP from the recorded data. We will provide representative results from a previously published study, in which fMRI-guided TMS was used concurrently with EEG to show that the face-selective N1 and the body-selective N1 component of the ERP are associated with distinct neural networks in extrastriate cortex. This method allows us to combine the high spatial resolution of fMRI with the high temporal resolution of TMS and EEG and therefore obtain a comprehensive understanding of the neural basis of various cognitive processes. PMID:24893706
Sadeh, Boaz; Yovel, Galit
Developments in deep brain stimulation using time dependent magnetic fields
The effect of head model complexity upon the strength of field in different brain regions for transcranial magnetic stimulation (TMS) has been investigated. Experimental measurements were used to verify the validity of magnetic field calculations and induced electric field calculations for three 3D human head models of varying complexity. Results show the inability for simplified head models to accurately determine the site of high fields that lead to neuronal stimulation and highlight the necessity for realistic head modeling for TMS applications.
Crowther, L. J.; Nlebedim, I. C.; Jiles, D. C.
Perfusion MRI Indexes Variability in the Functional Brain Effects of Theta-Burst Transcranial Magnetic Stimulation
Transcranial Magnetic Stimulation (TMS) is an important tool for testing causal relationships in cognitive neuroscience research. However, the efficacy of TMS can be variable across individuals and difficult to measure. This variability is especially a challenge when TMS is applied to regions without well-characterized behavioral effects, such as in studies using TMS on multi-modal areas in intrinsic networks. Here, we examined whether perfusion fMRI recordings of Cerebral Blood Flow (CBF), a quantitative measure sensitive to slow functional changes, reliably index variability in the effects of stimulation. Twenty-seven participants each completed four combined TMS-fMRI sessions during which both resting state Blood Oxygen Level Dependent (BOLD) and perfusion Arterial Spin Labeling (ASL) scans were recorded. In each session after the first baseline day, continuous theta-burst TMS (TBS) was applied to one of three locations: left dorsolateral prefrontal cortex (L dlPFC), left anterior insula/frontal operculum (L aI/fO), or left primary somatosensory cortex (L S1). The two frontal targets are components of intrinsic networks and L S1 was used as an experimental control. CBF changes were measured both before and after TMS on each day from a series of interleaved resting state and perfusion scans. Although TBS led to weak selective increases under the coil in CBF measurements across the group, individual subjects showed wide variability in their responses. TBS-induced changes in rCBF were related to TBS-induced changes in functional connectivity of the relevant intrinsic networks measured during separate resting-state BOLD scans. This relationship was selective: CBF and functional connectivity of these networks were not related before TBS or after TBS to the experimental control region (S1). Furthermore, subject groups with different directions of CBF change after TBS showed distinct modulations in the functional interactions of targeted networks. These results suggest that CBF is a marker of individual differences in the effects of TBS.
Gratton, Caterina; Lee, Taraz G.; Nomura, Emi M.; D'Esposito, Mark
Safety of Transcranial Magnetic Stimulation in Parkinson's Disease: A Review of the Literature
Background Transcranial magnetic stimulation (TMS) has been used in both physiological studies and, more recently, the therapy of Parkinson�s Disease (PD). Prior TMS studies in healthy subjects and other patient populations demonstrate a slight risk of seizures and other adverse events. Our goal was to estimate these risks and document other safety concerns specific to PD patients. Methods We performed an English-Language literature search through PudMed to review all TMS studies involving PD patients. We documented any seizures or other adverse events associated with these studies. Crude risks were calculated per subject and per session of TMS. Results We identified 84 single pulse (spTMS) and/or paired pulse (ppTMS) TMS studies involving 1091 patients and 77 repetitive TMS (rTMS) studies involving 1137 patients. Risk of adverse events was low in all protocols. spTMS and ppTMS risk per patient for any adverse event was 0.0018 (95% CI: 0.0002 � 0.0066) per patient and no seizures were encountered. Risk of an adverse event from rTMS was 0.040 (95% CI: 0.029 � 0.053) per patient and no seizures were reported. Other adverse events included transient headaches, scalp pain, tinnitus, nausea, increase in pre-existing pain, and muscle jerks. Transient worsening of Parkinsonian symptoms was noted in one study involving rTMS of the supplementary motor area (SMA). Conclusion We conclude that current TMS and rTMS protocols do not pose significant risks to PD patients. We would recommend that TMS users in this population follow the most recent safety guidelines but do not warrant additional precautions.
VonLoh, Matthew; Chen, Robert; Kluger, Benzi
Transcranial magnetic theta burst stimulation (TBS) differs from other high-frequency rTMS protocols because it induces plastic changes up to an hour despite lower stimulus intensity and shorter duration of stimulation. However, the effects of TBS on neuronal oscillations remain unclear. In this study, we used electroencephalography (EEG) to investigate changes of neuronal oscillations after continuous TBS (cTBS), the protocol that emulates long-term depression (LTD) form of synaptic plasticity. We randomly divided 26 healthy humans into two groups receiving either Active or Sham cTBS as control over the left primary motor cortex (M1). Post-cTBS aftereffects were assessed with behavioural measurements at rest using motor evoked potentials (MEPs) and at active state during the execution of a choice reaction time (RT) task in combination with continuous electrophysiological recordings. The cTBS-induced EEG oscillations were assessed using event-related power (ERPow), which reflected regional oscillatory activity of neural assemblies of ? (4�7.5 Hz), low ? (8�9.5 Hz), � (10�12.5 Hz), low ? (13�19.5 Hz), and high ? (20�30 Hz) brain rhythms. Results revealed 20-min suppression of MEPs and at least 30-min increase of ERPow modulation, suggesting that besides MEPs, EEG has the potential to provide an accurate cortical readout to assess cortical excitability and to investigate the interference of cortical oscillations in the human brain post-cTBS. We also observed a predominant modulation of ? frequency band, supporting the hypothesis that cTBS acts more on cortical level. Theta oscillations were also modulated during rest implying the involvement of independent cortical theta generators over the motor network post cTBS. This work provided more insights into the underlying mechanisms of cTBS, providing a possible link between synchronised neural oscillations and LTD in humans.
Noh, Nor Azila; Fuggetta, Giorgio; Manganotti, Paolo; Fiaschi, Antonio
[Possibilities of transcranial magnetic therapy and color and rhythm therapy in rehabilitation of ischemic stroke].
One hundred and sixteen post-stroke patients were studied in the early rehabilitation period. All patients were divided into 4 groups: 3 main and 1 control groups. Three main groups (87 patients) received transcranial magnetic therapy (TMT) and/or color and rhythm therapy (CRT) along with traditional treatment and the control group (29 patients) received only basic therapy. TMT was conducted using bitemporal technique, running regime with modulation frequency 1-10 Hz. In CRT, the alternating stimulation of the right and left eye with green and/or blue color with a period of 2-4 s and duration of luminescence 1s was applied. Each of 3 main groups received 2 treatment sessions with an interval of 1,5 month (1st - TMT, 2nd - CRT, 3rd - TMT + CRT). After the treatment, the marked positive changes were seen in all main groups, in particular in group 3. The improvement of neurologic symptoms on the B. Lindmark scale was higher by 9,5% in group 3 compared to the control one, on the Barthel index - by 8,8%, on MMSE and A. Luria and Schulte test - by 5,4 and 14,3%, respectively. Rheographic and encephalographic study revealed the significant improvement of hemodynamics and alpha-rhythm differentiation, decrease of patients with dysrhythmia by 14,6% in group 3 as compared to the control group. The best results were seen in the combination of TMT and CRT, TMT exerted a higher effect on the hemodynamics and CRT - on the psychoemotional state. Both therapies were well tolerated and had no side-effects. PMID:19672234
Sholomov, I I; Cherevashchenko, L A; Suprunov, O V; Ra?gorondski?, Iu M
Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.
Repetitive transcranial magnetic stimulation (rTMS) is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS) is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP), presumably reflecting long-term depression (LTD) -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1) reproduce cortico-spinal depression by LF rTMS in rats, (2) establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3) test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR), by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered. PMID:24646791
Muller, Paul A; Dhamne, Sameer C; Vahabzadeh-Hagh, Andrew M; Pascual-Leone, Alvaro; Jensen, Frances E; Rotenberg, Alexander
Acute effects of repetitive transcranial magnetic stimulation on attentional control are related to antidepressant outcomes
Background Repetitive transcranial magnetic stimulation (rTMS) applied over the dorsolateral prefrontal cortex (DLPFC) is a new treatment procedure that holds promise of more insight into the pathophysiology of depression because the DLPFC may play an important role in the interplay between emotional and attentional information processing. We sought to investigate whether acute neurocognitive effects of rTMS are related to antidepressant outcomes. Methods Between January 2005 and May 2007, we examined the effects of a single session compared with 2 weeks of rTMS over the left DLPFC on cognition and mood in therapy-resistant patients with depression. We used a crossover placebo-controlled double-blind design and differentiated rTMS treatment responders and nonresponders. We used a task-switching paradigm to measure cognitive function. Results After 2 weeks of high-frequency rTMS over the left DLPFC, depressive symptoms improved in more than half (53%) of our therapy-resistant population. After a single session, mood did not improve but attentional control was increased solely within our group of treatment responders. Limitations Our results should be interpreted as preliminary because our sample was small and because the cognitive task we used has not been tested for validity and reliability. In addition, despite minimal stimulation of the DLPFC during sham stimulation, it is possible that the stiumlation was partially active. Finally, benzodiazepines may have had impairing effects on the attentional task. Conclusion Cognitive reactivity after a single session of rTMS may hold promise as a predictor of beneficial treatment outcomes. Moreover, within the group of responders, attentional control appears to play an important role in the progress of mood disorders.
Vanderhasselt, Marie-Anne; De Raedt, Rudi; Leyman, Lemke; Baeken, Chris
Repetitive Transcranial Magnetic Stimulation of the Dorsolateral Prefrontal Cortex Reduces Nicotine Cue Craving
Background Repetitive transcranial magnetic stimulation (rTMS) can non-invasively stimulate the brain and transiently amplify or block behaviors mediated through a region. We hypothesized that a single high-frequency rTMS session over the left dorsolateral prefrontal cortex (DLPFC) would reduce cue craving for cigarettes compared to a sham TMS session. Methods Sixteen non-treatment seeking, nicotine-dependent participants were randomized to receive either real high-frequency rTMS (10 Hz, 100% resting motor threshold, 5 second-on, 10 second-off for 15 minutes; 3000 pulses) or active sham (eSham) TMS over the DLPFC in two visits with one week between visits. The participants received cue exposure before and after rTMS and rated their craving after each block of cue presentation. Results Stimulation of the left DLFPC with real, but not sham, rTMS reduced craving significantly from baseline (64.1� 5.9 vs. 45.7�6.4, t = 2.69, p = 0.018). When compared to neutral cue craving, the effect of real TMS on cue craving was significantly greater than the effect of sham TMS (12.5 �10.4 vs. ?9.1�10.4; t = 2.07, p = 0.049). More decreases in subjective craving induced by TMS correlated positively with higher Fagerstr�m Test for Nicotine Dependence (FTND) score (r = 0.58, p = 0.031) and more cigarettes smoked per day (r = 0.57, p = 0.035). Conclusions One session of high frequency rTMS (10 Hz) of the left DLPFC significantly reduced subjective craving induced by smoking cues in nicotine-dependent participants. Further studies are needed to explore the use of rTMS as an aid to smoking cessation.
Li, Xingbao; Hartwell, Karen J.; Owens, Max; LeMatty, Todd; Borckardt, Jeffrey; Hanlon, Colleen; Brady, Kathleen T.; George, Mark S.
Posttraining transcranial magnetic stimulation of striate cortex disrupts consolidation early in visual skill learning.
Practice-induced improvements in skilled performance reflect "offline " consolidation processes extending beyond daily training sessions. According to visual learning theories, an early, fast learning phase driven by high-level areas is followed by a late, asymptotic learning phase driven by low-level, retinotopic areas when higher resolution is required. Thus, low-level areas would not contribute to learning and offline consolidation until late learning. Recent studies have challenged this notion, demonstrating modified responses to trained stimuli in primary visual cortex (V1) and offline activity after very limited training. However, the behavioral relevance of modified V1 activity for offline consolidation of visual skill memory in V1 after early training sessions remains unclear. Here, we used neuronavigated transcranial magnetic stimulation (TMS) directed to a trained retinotopic V1 location to test for behaviorally relevant consolidation in human low-level visual cortex. Applying TMS to the trained V1 location within 45 min of the first or second training session strongly interfered with learning, as measured by impaired performance the next day. The interference was conditional on task context and occurred only when training in the location targeted by TMS was followed by training in a second location before TMS. In this condition, high-level areas may become coupled to the second location and uncoupled from the previously trained low-level representation, thereby rendering consolidation vulnerable to interference. Our data show that, during the earliest phases of skill learning in the lowest-level visual areas, a behaviorally relevant form of consolidation exists of which the robustness is controlled by high-level, contextual factors. PMID:22323712
De Weerd, Peter; Reithler, Joel; van de Ven, Vincent; Been, Marin; Jacobs, Christianne; Sack, Alexander T
Neurocognitive effects of repetitive transcranial magnetic stimulation in adolescents with major depressive disorder.
Objectives: It is estimated that 30-40% of adolescents with major depressive disorder (MDD) do not receive full benefit from current antidepressant therapies. Repetitive transcranial magnetic stimulation (rTMS) is a novel therapy approved by the US Food and Drug Administration to treat adults with MDD. Research suggests rTMS is not associated with adverse neurocognitive effects in adult populations; however, there is no documentation of its neurocognitive effects in adolescents. This is a secondary post hoc analysis of neurocognitive outcome in adolescents who were treated with open-label rTMS in two separate studies. Methods: Eighteen patients (mean age, 16.2?�?1.1?years; 11 females, 7 males) with MDD who failed to adequately respond to at least one antidepressant agent were enrolled in the study. Fourteen patients completed all 30 rTMS treatments (5?days/week, 120% of motor threshold, 10?Hz, 3,000 stimulations per session) applied to the left dorsolateral prefrontal cortex. Depression was rated using the Children's Depression Rating Scale-Revised. Neurocognitive evaluation was performed at baseline and after completion of 30 rTMS treatments with the Children's Auditory Verbal Learning Test (CAVLT) and Delis-Kaplan Executive Function System Trail Making Test. Results: Over the course of 30 rTMS treatments, adolescents showed a substantial decrease in depression severity. Commensurate with improvement in depressive symptoms was a statistically significant improvement in memory and delayed verbal recall. Other learning and memory indices and executive function remained intact. Neither participants nor their family members reported clinically meaningful changes in neurocognitive function. Conclusion: These preliminary findings suggest rTMS does not adversely impact neurocognitive functioning in adolescents and may provide subtle enhancement of verbal memory as measured by the CAVLT. Further controlled investigations with larger sample sizes and rigorous trial designs are warranted to confirm and extend these findings. PMID:24376426
Wall, Christopher A; Croarkin, Paul E; McClintock, Shawn M; Murphy, Lauren L; Bandel, Lorelei A; Sim, Leslie A; Sampson, Shirlene M
Neck muscle responses evoked by transcranial magnetic stimulation of the human frontal eye fields.
Transcranial magnetic stimulation (TMS) provides a non-invasive means of investigating brain function. Whereas TMS of the human frontal eye fields (FEFs) does not induce saccades, electrical stimulation of the monkey FEF evokes eye-head gaze shifts, with neck muscle responses evoked at stimulation levels insufficient to evoke a saccade. These animal results motivated us to examine whether TMS of the FEF (TMS-FEF) in humans evokes a neck muscle response. Subjects performed memory-guided saccades to the left or right while TMS (two pulses at 20?Hz) was delivered on 30% of trials to the left FEF coincident with saccade instruction. As reported previously, TMS-FEF decreased contralateral saccade reaction times. We simultaneously recorded the activity of splenius capitis (SPL) (an ipsilateral head turner). TMS-FEF evoked a lateralized increase in the activity of the right SPL but not the left SPL, consistent with the recruitment of a contralateral head-turning synergy. In some subjects, the evoked neck muscle response was time-locked to stimulation, whereas in others the evoked response occurred around the time of the saccade. Importantly, evoked responses were greater when TMS was applied to the FEF engaged in contralateral saccade preparation, with even greater evoked responses preceding shorter latency saccades. These results provide new insights into both the nature of TMS and the human oculomotor system, demonstrating that TMS-FEF engages brainstem oculomotor circuits in a manner consistent with a general role in eye-head gaze orienting. Our results also suggest that pairing neck muscle recordings with TMS-FEF provides a novel way of assaying the covert preparation of oculomotor plans. PMID:21645109
Goonetilleke, Samanthi C; Gribble, Paul L; Mirsattari, Seyed M; Doherty, Timothy J; Corneil, Brian D
Specificity of human parietal saccade and reach regions during transcranial magnetic stimulation.
Single-unit recordings in macaque monkeys have identified effector-specific regions in posterior parietal cortex (PPC), but functional neuroimaging in the human has yielded controversial results. Here we used on-line repetitive transcranial magnetic stimulation (rTMS) to determine saccade and reach specificity in human PPC. A short train of three TMS pulses (separated by an interval of 100 ms) was delivered to superior parieto-occipital cortex (SPOC), a region over the midposterior intraparietal sulcus (mIPS), and a site close to caudal IPS situated over the angular gyrus (AG) during a brief memory interval while subjects planned either a saccade or reach with the left or right hand. Behavioral measures then were compared to controls without rTMS. Stimulation of mIPS and AG produced similar patterns: increased end-point variability for reaches and decreased saccade accuracy for contralateral targets. In contrast, stimulation of SPOC deviated reach end points toward visual fixation and had no effect on saccades. Contralateral-limb specificity was highest for AG and lowest for SPOC. Visual feedback of the hand negated rTMS-induced disruptions of the reach plan for mIPS and AG, but not SPOC. These results suggest that human SPOC is specialized for encoding retinally peripheral reach goals, whereas more anterior-lateral regions (mIPS and AG) along the IPS possess overlapping maps for saccade and reach planning and are more closely involved in motor details (i.e., planning the reach vector for a specific hand). This work provides the first causal evidence for functional specificity of these parietal regions in healthy humans. PMID:20881123
Vesia, Michael; Prime, Steven L; Yan, Xiaogang; Sergio, Lauren E; Crawford, J Douglas
Low-frequency repetitive transcranial magnetic stimulation for dyskinesia and motor performance in Parkinson's disease.
Dyskinesias are one of the most frequent and disabling complications of the long-term treatment of Parkinson's disease (PD). Although the cause is not completely understood, it appears that an imbalance between excitatory and inhibitory inputs from the basal ganglia to the motor cortex leads to overactivation of motor and premotor areas. Overactivation of the supplementary motor area (SMA) has been observed in neuroimaging studies in dyskinetic PD patients. We investigated the effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) of the SMA on levodopa-induced dyskinesias (LID) and motor performance in PD. We tested whether longer duration (10days) and higher number of total pulses (1800 pulses) would enhance the beneficial effect. Seventeen dyskinetic PD patients were randomly assigned to real rTMS or sham (placebo) rTMS, and 1Hz rTMS or sham rTMS was applied over the SMA for 10 consecutive days. Patients were assessed at baseline and 1day after the last rTMS with a levodopa challenge test, and video recordings were taken. Dyskinesias and motor performance were rated off-line by two blinded raters using video recordings. After 10days of treatment with rTMS, we observed that 1Hz rTMS delivered over the SMA had decreased LID lasting for 24hours without a change in motor performance, whereas sham rTMS induced no significant change in dyskinesia scores. These results support a possible therapeutic effect of low-frequency rTMS in LID. However, in order to suggest rTMS as an effective treatment, long-term observations and further investigations with a larger patient population are essential. PMID:24631324
Say?n, Sevgi; Cakmur, Raif; Yener, G�rsev G; Yaka, Erdem; U?urel, Burcu; Uzunel, Fatma
Perfusion MRI indexes variability in the functional brain effects of theta-burst transcranial magnetic stimulation.
Transcranial Magnetic Stimulation (TMS) is an important tool for testing causal relationships in cognitive neuroscience research. However, the efficacy of TMS can be variable across individuals and difficult to measure. This variability is especially a challenge when TMS is applied to regions without well-characterized behavioral effects, such as in studies using TMS on multi-modal areas in intrinsic networks. Here, we examined whether perfusion fMRI recordings of Cerebral Blood Flow (CBF), a quantitative measure sensitive to slow functional changes, reliably index variability in the effects of stimulation. Twenty-seven participants each completed four combined TMS-fMRI sessions during which both resting state Blood Oxygen Level Dependent (BOLD) and perfusion Arterial Spin Labeling (ASL) scans were recorded. In each session after the first baseline day, continuous theta-burst TMS (TBS) was applied to one of three locations: left dorsolateral prefrontal cortex (L dlPFC), left anterior insula/frontal operculum (L aI/fO), or left primary somatosensory cortex (L S1). The two frontal targets are components of intrinsic networks and L S1 was used as an experimental control. CBF changes were measured both before and after TMS on each day from a series of interleaved resting state and perfusion scans. Although TBS led to weak selective increases under the coil in CBF measurements across the group, individual subjects showed wide variability in their responses. TBS-induced changes in rCBF were related to TBS-induced changes in functional connectivity of the relevant intrinsic networks measured during separate resting-state BOLD scans. This relationship was selective: CBF and functional connectivity of these networks were not related before TBS or after TBS to the experimental control region (S1). Furthermore, subject groups with different directions of CBF change after TBS showed distinct modulations in the functional interactions of targeted networks. These results suggest that CBF is a marker of individual differences in the effects of TBS. PMID:24992641
Gratton, Caterina; Lee, Taraz G; Nomura, Emi M; D'Esposito, Mark
Isolating a cerebellar contribution to rapid visual attention using transcranial magnetic stimulation
Patient and neuroimaging research have provided increasing support for a role of the posterior-lateral cerebellum in cognition, particularly attention. During rapid serial visual presentation, when two targets are presented in close temporal proximity (<500 ms), accuracy at detecting the second target (T2) suffers. This phenomenon is known as the attentional blink (AB), and in cerebellar lesion patients this effect is exaggerated. Damage to the cerebellum may thus disrupt the use of attentional resources during stimulus processing conditions that are temporally demanding. There are reciprocal connections between the cerebral cortex and the contralateral cerebellum, these connections allow for the possibility that lateralized functions in the cerebral cortex (such as language) remain lateralized in the cerebellum. The purpose of this study was to investigate the temporal characteristics of the cerebellar contribution to the AB and to functionally localize the contribution of the cerebellum to the AB using transcranial magnetic stimulation (TMS). We hypothesized that T2 accuracy would decrease after right cerebellar stimulation when the delay between the first target (T1) and T2 was short (120�400 ms) compared to long (720�960 ms). We used continuous theta burst stimulation (cTBS), a form of TMS, to transiently inhibit a focal population of neurons in the left and right posterior-lateral cerebellum of healthy participants (n = 45). Three groups of participants (n = 15) performed the AB before and after either sham, left, or right cerebellar stimulation. The results of this cTBS study support our hypothesis. During the short delay, participants in the right cTBS group showed a greater AB magnitude compared to both the left and sham cTBS groups (p < 0.05). No difference in T2 detection was found over long delays. The results provide further support for a cerebellar contribution to an integrated neural network recruited during temporally demanding attention-based tasks.
Arasanz, Carla P.; Staines, W. Richard; Schweizer, Tom A.
5 Hz repetitive transcranial magnetic stimulation over the ipsilesional sensory cortex enhances motor learning after stroke
Sensory feedback is critical for motor learning, and thus to neurorehabilitation after stroke. Whether enhancing sensory feedback by applying excitatory repetitive transcranial magnetic stimulation (rTMS) over the ipsilesional primary sensory cortex (IL-S1) might enhance motor learning in chronic stroke has yet to be investigated. The present study investigated the effects of 5 Hz rTMS over IL-S1 paired with skilled motor practice on motor learning, hemiparetic cutaneous somatosensation, and motor function. Individuals with unilateral chronic stroke were pseudo-randomly divided into either Active or Sham 5 Hz rTMS groups (n = 11/group). Following stimulation, both groups practiced a Serial Tracking Task (STT) with the hemiparetic arm; this was repeated for 5 days. Performance on the STT was quantified by response time, peak velocity, and cumulative distance tracked at baseline, during the 5 days of practice, and at a no-rTMS retention test. Cutaneous somatosensation was measured using two-point discrimination. Standardized sensorimotor tests were performed to assess whether the effects might generalize to impact hemiparetic arm function. The active 5 Hz rTMS + training group demonstrated significantly greater improvements in STT performance {response time [F(1, 286.04) = 13.016, p < 0.0005], peak velocity [F(1, 285.95) = 4.111, p = 0.044], and cumulative distance [F(1, 285.92) = 4.076, p = 0.044]} and cutaneous somatosensation [F(1, 21.15) = 8.793, p = 0.007] across all sessions compared to the sham rTMS + training group. Measures of upper extremity motor function were not significantly different for either group. Our preliminary results suggest that, when paired with motor practice, 5 Hz rTMS over IL-S1 enhances motor learning related change in individuals with chronic stroke, potentially as a consequence of improved cutaneous somatosensation, however no improvement in general upper extremity function was observed.
Brodie, Sonia M.; Meehan, Sean; Borich, Michael R.; Boyd, Lara A.
The contribution of transcranial magnetic stimulation in the functional evaluation of microcircuits in human motor cortex
Although transcranial magnetic stimulation (TMS) activates a number of different neuron types in the cortex, the final output elicited in corticospinal neurones is surprisingly stereotyped. A single TMS pulse evokes a series of descending corticospinal volleys that are separated from each other by about 1.5 ms (i.e., ~670 Hz). This evoked descending corticospinal activity can be directly recorded by an epidural electrode placed over the high cervical cord. The earliest wave is thought to originate from the direct activation of the axons of fast-conducting pyramidal tract neurones (PTN) and is therefore termed �D� wave. The later waves are thought to originate from indirect, trans-synaptic activation of PTNs and are termed �I� waves. The anatomical and computational characteristics of a canonical microcircuit model of cerebral cortex composed of layer II and III and layer V excitatory pyramidal cells, inhibitory interneurons, and cortico-cortical and thalamo-cortical inputs can account for the main characteristics of the corticospinal activity evoked by TMS including its regular and rhythmic nature, the stimulus intensity-dependence and its pharmacological modulation. In this review we summarize present knowledge of the physiological basis of the effects of TMS of the human motor cortex describing possible interactions between TMS and simple canonical microcircuits of neocortex. According to the canonical model, a TMS pulse induces strong depolarization of the excitatory cells in the superficial layers of the circuit. This leads to highly synchronized recruitment of clusters of excitatory neurons, including layer V PTNs, and of inhibitory interneurons producing a high frequency (~670 Hz) repetitive discharge of the corticospinal axons. The role of the inhibitory circuits is crucial to entrain the firing of the excitatory networks to produce a high-frequency discharge and to control the number and magnitude of evoked excitatory discharge in layer V PTNs. In summary, simple canonical microcircuits of neocortex can explain activation of corticospinal neurons in human motor cortex by TMS.
Di Lazzaro, Vincenzo; Ziemann, Ulf
The contribution of transcranial magnetic stimulation in the functional evaluation of microcircuits in human motor cortex.
Although transcranial magnetic stimulation (TMS) activates a number of different neuron types in the cortex, the final output elicited in corticospinal neurones is surprisingly stereotyped. A single TMS pulse evokes a series of descending corticospinal volleys that are separated from each other by about 1.5 ms (i.e., ~670 Hz). This evoked descending corticospinal activity can be directly recorded by an epidural electrode placed over the high cervical cord. The earliest wave is thought to originate from the direct activation of the axons of fast-conducting pyramidal tract neurones (PTN) and is therefore termed "D" wave. The later waves are thought to originate from indirect, trans-synaptic activation of PTNs and are termed "I" waves. The anatomical and computational characteristics of a canonical microcircuit model of cerebral cortex composed of layer II and III and layer V excitatory pyramidal cells, inhibitory interneurons, and cortico-cortical and thalamo-cortical inputs can account for the main characteristics of the corticospinal activity evoked by TMS including its regular and rhythmic nature, the stimulus intensity-dependence and its pharmacological modulation. In this review we summarize present knowledge of the physiological basis of the effects of TMS of the human motor cortex describing possible interactions between TMS and simple canonical microcircuits of neocortex. According to the canonical model, a TMS pulse induces strong depolarization of the excitatory cells in the superficial layers of the circuit. This leads to highly synchronized recruitment of clusters of excitatory neurons, including layer V PTNs, and of inhibitory interneurons producing a high frequency (~670 Hz) repetitive discharge of the corticospinal axons. The role of the inhibitory circuits is crucial to entrain the firing of the excitatory networks to produce a high-frequency discharge and to control the number and magnitude of evoked excitatory discharge in layer V PTNs. In summary, simple canonical microcircuits of neocortex can explain activation of corticospinal neurons in human motor cortex by TMS. PMID:23407686
Cortical excitability changes after high-frequency repetitive transcranial magnetic stimulation for central poststroke pain.
Central poststroke pain (CPSP) is one of the most refractory chronic pain syndromes. Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex has been demonstrated to provide moderate pain relief for CPSP. However, the mechanism underlying the pain relief remains unclear. The objective of this study was to assess changes in cortical excitability in patients with intractable CPSP before and after rTMS of the primary motor cortex. Subjects were 21 patients with CPSP of the hand who underwent rTMS. The resting motor threshold, the amplitude of the motor evoked potential, duration of the cortical silent period, short interval intracortical inhibition, and intracortical facilitation were measured as parameters of cortical excitability before and after navigation-guided 5 Hz rTMS of the primary motor cortex corresponding to the painful hand. Pain reduction from rTMS was assessed with a visual analog scale. The same parameters were measured in both hemispheres of 8 healthy controls. Eight of 21 patients experienced ? 30% pain reduction after rTMS (responders). The resting motor threshold in the patients was higher than those in the controls at baseline (P=.035). Intracortical facilitation in the responders was lower than in the controls and the nonresponders at baseline (P=.035 and P=.019), and significantly increased after rTMS (P=.039). There were no significant differences or changes in the other parameters. Our findings suggest that restoration of abnormal cortical excitability might be one of the mechanisms underlying pain relief as a result of rTMS in CPSP. PMID:23707310
Hosomi, Koichi; Kishima, Haruhiko; Oshino, Satoru; Hirata, Masayuki; Tani, Naoki; Maruo, Tomoyuki; Yorifuji, Shiro; Yoshimine, Toshiki; Saitoh, Youichi
Investigating Representations of Facial Identity in Human Ventral Visual Cortex with Transcranial Magnetic Stimulation
The occipital face area (OFA) is face-selective. This enhanced activation to faces could reflect either generic face and shape-related processing or high-level conceptual processing of identity. Here we examined these two possibilities using a state-dependent transcranial magnetic stimulation (TMS) paradigm. The lateral occipital (LO) cortex which is activated non-selectively by various types of objects served as a control site. We localized OFA and LO on a per-participant basis using functional MRI. We then examined whether TMS applied to either of these regions affected the ability of participants to decide whether two successively presented and physically different face images were of the same famous person or different famous people. TMS was applied during the delay between first and second face presentations to investigate whether neuronal populations in these regions played a causal role in mediating the behavioral effects of identity repetition. Behaviorally we found a robust identity repetition effect, with shorter reaction times (RTs) when identity was repeated, regardless of the fact that the pictures were physically different. Surprisingly, TMS applied over LO (but not OFA) modulated overall RTs, compared to the No-TMS condition. But critically, we found no effects of TMS to either area that were modulated by identity repetition. Thus, we found no evidence to suggest that OFA or LO contain neuronal representations selective for the identity of famous faces which play a causal role in identity processing. Instead, these brain regions may be involved in the processing of more generic features of their preferred stimulus categories.
Gilaie-Dotan, Sharon; Silvanto, Juha; Schwarzkopf, Dietrich S.; Rees, Geraint
Interaction of transcutaneous spinal stimulation and transcranial magnetic stimulation in human leg muscles.
Transcutaneous spinal stimulation is a noninvasive method that can activate dorsal and/or ventral roots depending on the location and intensity of stimulation. Reflex root-evoked potentials (REPs) were studied in muscles that traditionally evoke large (soleus) and small H-reflexes (tibialis anterior), as well as muscles where H-reflexes are difficult to study (hamstrings). This study characterizes the interaction of the REP and the motor-evoked potential (MEP). Transcranial magnetic stimulation (TMS) delivered 11-25 ms before spinal stimulation resulted in more than linear summation of the two responses. Because of overlap, the modulation was quantified after subtracting the contribution of the conditioning MEP or REP. At rest, the mean-rectified soleus response was facilitated by up to ~250 ?V (21-times the MEP or 161% of the REP). The increases were more reliable during a voluntary contraction (up to ~300 ?V, 517% of the MEP or 181% of the REP). At the 13-ms interval, the mean-rectified response in the pre-contracted hamstrings was increased by 227% of the MEP or 300% of the REP. In some subjects, TMS could also eliminate the post-activation depression produced using two spinal stimuli, confirming that the interaction can extend to presynaptic spinal neurons. The spatiotemporal facilitation in tibialis anterior was not significant. However, the large MEP was facilitated when the spinal stimulus preceded TMS by 100-150 ms, presumably because of rebound excitation. These strong interactions may be important for inducing motor plasticity and improved training procedures for recovery after neurological damage. PMID:24531641
Roy, Fran�ois D; Bosgra, Dillen; Stein, Richard B
Transcranial magnetic stimulation-induced global propagation of transient phase resetting associated with directional information flow.
Electroencephalogram (EEG) phase synchronization analyses can reveal large-scale communication between distant brain areas. However, it is not possible to identify the directional information flow between distant areas using conventional phase synchronization analyses. In the present study, we applied transcranial magnetic stimulation (TMS) to the occipital area in subjects who were resting with their eyes closed, and analyzed the spatial propagation of transient TMS-induced phase resetting by using the transfer entropy (TE), to quantify the causal and directional flow of information. The time-frequency EEG analysis indicated that the theta (5 Hz) phase locking factor (PLF) reached its highest value at the distant area (the motor area in this study), with a time lag that followed the peak of the transient PLF enhancements of the TMS-targeted area at the TMS onset. Phase-preservation index (PPI) analyses demonstrated significant phase resetting at the TMS-targeted area and distant area. Moreover, the TE from the TMS-targeted area to the distant area increased clearly during the delay that followed TMS onset. Interestingly, the time lags were almost coincident between the PLF and TE results (152 vs. 165 ms), which provides strong evidence that the emergence of the delayed PLF reflects the causal information flow. Such tendencies were observed only in the higher-intensity TMS condition, and not in the lower-intensity or sham TMS conditions. Thus, TMS may manipulate large-scale causal relationships between brain areas in an intensity-dependent manner. We demonstrated that single-pulse TMS modulated global phase dynamics and directional information flow among synchronized brain networks. Therefore, our results suggest that single-pulse TMS can manipulate both incoming and outgoing information in the TMS-targeted area associated with functional changes. PMID:24723875
Kawasaki, Masahiro; Uno, Yutaka; Mori, Jumpei; Kobata, Kenji; Kitajo, Keiichi
Therapeutic effects of repetitive transcranial magnetic stimulation in an animal model of Parkinson's disease.
Repetitive transcranial magnetic stimulation (rTMS) is used to treat neurological diseases such as stroke and Parkinson's disease (PD). Although rTMS has been used clinically, its underlying therapeutic mechanism remains unclear. The objective of the present study was to clarify the neuroprotective effect and therapeutic mechanism of rTMS in an animal model of PD. Adult Sprague-Dawley rats were unilaterally injected with 6-hydroxydopamine (6-OHDA) into the right striatum. Rats with PD were then treated with rTMS (circular coil, 10 Hz, 20 min/day) daily for 4 weeks. Behavioral assessments such as amphetamine-induced rotational test and treadmill locomotion test were performed, and the dopaminergic (DA) neurons of substantia nigra pas compacta (SNc) and striatum were histologically examined. Expression of neurotrophic/growth factors was also investigated by multiplex ELISA, western blotting analysis and immunohistochemistry 4 weeks after rTMS application. Among the results, the number of amphetamine-induced rotations was significantly lower in the rTMS group than in the control group at 4 weeks post-treatment. Treadmill locomotion was also significantly improved in the rTMS-treated rats. Tyrosine hydroxylase-positive DA neurons and DA fibers in rTMS group rats were greater than those in untreated group in both ipsilateral SNc and striatum, respectively. The expression levels of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, platelet-derived growth factor, and vascular endothelial growth factor were elevated in both the 6-OHDA-injected hemisphere and the SNc of the rTMS-treated rats. In conclusion, rTMS treatment improved motor functions and survival of DA neurons, suggesting that the neuroprotective effect of rTMS treatment might be induced by upregulation of neurotrophic/growth factors in the PD animal model. PMID:23998987
Lee, Ji Yong; Kim, Sung Hoon; Ko, Ah-Ra; Lee, Jin Suk; Yu, Ji Hea; Seo, Jung Hwa; Cho, Byung Pil; Cho, Sung-Rae
Changes in Voluntary Activation Assessed by Transcranial Magnetic Stimulation during Prolonged Cycling Exercise
Maximal central motor drive is known to decrease during prolonged exercise although it remains to be determined whether a supraspinal deficit exists, and if so, when it appears. The purpose of this study was to evaluate corticospinal excitability and muscle voluntary activation before, during and after a 4-h cycling exercise. Ten healthy subjects performed three 80-min bouts on an ergocycle at 45% of their maximal aerobic power. Before exercise and immediately after each bout, neuromuscular function was evaluated in the quadriceps femoris muscles under isometric conditions. Transcranial magnetic stimulation was used to assess voluntary activation at the cortical level (VATMS), corticospinal excitability via motor-evoked potential (MEP) and intracortical inhibition by cortical silent period (CSP). Electrical stimulation of the femoral nerve was used to measure voluntary activation at the peripheral level (VAFNES) and muscle contractile properties. Maximal voluntary force was significantly reduced after the first bout (13�9%, P<0.01) and was further decreased (25�11%, P<0.001) at the end of exercise. CSP remained unchanged throughout the protocol. Rectus femoris and vastus lateralis but not vastus medialis MEP normalized to maximal M-wave amplitude significantly increased during cycling. Finally, significant decreases in both VATMS and VAFNES (?8%, P<0.05 and ?14%, P<0.001 post-exercise, respectively) were observed. In conclusion, reductions in VAFNES after a prolonged cycling exercise are partly explained by a deficit at the cortical level accompanied by increased corticospinal excitability and unchanged intracortical inhibition. When comparing the present results with the literature, this study highlights that changes at the cortical and/or motoneuronal levels depend not only on the type of exercise (single-joint vs. whole-body) but also on exercise intensity and/or duration.
Perrey, Stephane; Temesi, John; Wuyam, Bernard; Levy, Patrick; Verges, Samuel; Millet, Guillaume Y.
Excitatory repetitive transcranial magnetic stimulation induces improvements in chronic post-stroke aphasia
Summary Background Aphasia affects 1/3 of stroke patients with improvements noted only in some of them. The goal of this exploratory study was to provide preliminary evidence regarding safety and efficacy of fMRI-guided excitatory repetitive transcranial magnetic stimulation (rTMS) applied to the residual left-hemispheric Broca�s area for chronic aphasia treatment. Material/Methods We enrolled 8 patients with moderate or severe aphasia >1 year after LMCA stroke. Linguistic battery was administered pre-/post-rTMS; a semantic decision/tone decision (SDTD) fMRI task was used to localize left-hemispheric Broca�s area. RTMS protocol consisted of 10 daily treatments of 200 seconds each using an excitatory stimulation protocol called intermittent theta burst stimulation (iTBS). Coil placement was targeted individually to the left Broca�s. Results 6/8 patients showed significant pre-/post-rTMS improvements in semantic fluency (p=0.028); they were able to generate more appropriate words when prompted with a semantic category. Pre-/post-rTMS fMRI maps showed increases in left fronto-temporo-parietal language networks with a significant left-hemispheric shift in the left frontal (p=0.025), left temporo-parietal (p=0.038) regions and global language LI (p=0.018). Patients tended to report subjective improvement on Communicative Activities Log (mini-CAL; p=0.075). None of the subjects reported ill effects of rTMS. Conclusions FMRI-guided, excitatory rTMS applied to the affected Broca�s area improved language skills in patients with chronic post-stroke aphasia; these improvements correlated with increased language lateralization to the left hemisphere. This rTMS protocol appears to be safe and should be further tested in blinded studies assessing its short- and long-term safety/efficacy for post-stroke aphasia rehabilitation.
Szaflarski, Jerzy P.; Vannest, Jennifer; Wu, Steve W.; DiFrancesco, Mark W.; Banks, Christi; Gilbert, Donald L.
Topiramate modulates excitability of the occipital cortex when measured by transcranial magnetic stimulation.
The aim of this study was to measure differences in occipital cortex excitability in migraineurs before and after administration of topiramate. We have previously demonstrated occipital cortex hyperexcitability in migraine using an objective technique of magnetic suppression of perceptual accuracy (MSPA). We hypothesized that a neuromodulator such as topiramate would demonstrate differences in MSPA in migraine compared with baseline. Ten migraine patients were recruited. To assess inhibitory function MSPA was measured using the following protocol. Timed transcranial magnetic stimulation were delivered at interstimulus intervals (ISI) varying from 40 to 190 ms (eight stimulations at each ISI) at 60% stimulus intensity. Subjects were asked to report letters projected at a fixed luminance on the screen. Visual suppression was calculated based on the number of errors the subjects made using automated analysis. This procedure was repeated at a minimum of two different dosages of topiramate when it was titrated for optimal migraine control. The interim dose was that at which an improvement in headache frequency was first observed, and the optimal dose was that at which the patient had a ? 50% reduction in headache frequency, or had reached a 100-mg dose. The mean [standard error (s.e.)] level of letters reported correct at baseline at 100-ms ISI was 91.6 (3.4) compared with 48.5 (6.0) (P = 0.001) at an optimal dose of topiramate. Dose ranged from 50 to 100 mg; the average dose was 75 mg. The interim dose for most patients was 50 mg; the mean (s.e.) percentage of letters reported correct at interim was 75.9 (6.2) compared with baseline (P = 0.01). Mean number of headaches at baseline was 27 per month, compared with eight headaches per month at interim dose and four headaches per month at optimal dose. There was no significant correlation between mean change in frequency of headache and mean change in inhibition from baseline to optimal dose (0.04, P = 0.89). Topiramate modulates occipital cortex excitability in chronic migraine possibly via mechanisms of cortical inhibition. Since there was not a strong correlation between the degree of inhibition and reduction of migraine frequency, it would appear that topiramate did have an independent effect on cortical excitability that was not dependent on reduction in migraine frequency. PMID:19732073
Aurora, S K; Barrodale, P M; Vermaas, A R; Rudra, C B
The effect of head and coil modeling for the calculation of induced electric field during transcranial magnetic stimulation.
In the present work we studied some of the features related to transcranial magnetic stimulation (TMS) computational modeling. Particularly we investigated the impact of head model resolution on the estimated distribution of the induced electric field, as well as the role of the stimulating magnetic coil model in TMS. Using the impedance method we calculated the induced electric field inside a realistic numerical phantom of the human head from a commercially available eight-shaped coil, which was modeled in two ways. The results showed that finer resolution of the model has better performance at tissue interfaces eliminating numerical artifacts of local peaks. Furthermore, the geometrical details of a TMS coil must be taken into account since the predicted amount of volume of brain tissue involved can have great variation. Finally, the secondary magnetic field that is generated by the induced eddy currents in the tissues can be neglected. PMID:23872490
Tachas, Nikolaos J; Samaras, Theodoros
Safety study of 50 Hz repetitive transcranial magnetic stimulation in patients with Parkinson's disease
Objective Repetitive transcranial magnetic stimulation (rTMS) has shown promising results in treating Parkinson�s disease (PD), but the best values for rTMS parameters are not established. 50 Hz rTMS may be superior to ? 25 Hz rTMS investigated so far. The objective of this study was to determine if 50 Hz rTMS could be delivered safely in PD patients since current safety limits are exceeded. Methods 50 Hz rTMS was applied with a circular coil on the primary motor cortex (M1). Stimulation intensity was first tested at 60% rest motor threshold [RMT] and 0.5 sec train duration and then increased in 0.5 sec steps to 2 sec, and by 10% steps to 90% RMT. Multi-channel electromyography (EMG) was recorded to control for signs of increasing time-locked EMG activity including correlates of the spread of excitation and after-discharges, or an increase of M1 excitability. Pre- and post-50 Hz rTMS assessments included EEG, Unified Parkinson Disease Rating Scale (UPDRS), Grooved Pegboard Test, Serial Reaction Time Task (SRTT), Folstein Mini-Mental Status Examination (MMSE) and Verbal Fluency to control for motor and cognitive side effects. Results Ten PD patients were investigated. Multi-channel EMG showed no signs of increased time-locked EMG activity including correlates of the spread of excitation and after-discharges, or increased M1 excitability in 9 patients. A PD patient with bi-temporal spikes in the pre-testing EEG had clinical and EMG correlates of spread of excitation at 90% RMT, but no seizure activity. Pre- and post-50 Hz assessment showed no changes. No adverse events were observed. 50 Hz rTMS was well tolerated except by one patient who wished to terminate the study due to facial muscle stimulation. Conclusion 50 Hz rTMS at an intensity of 90% RMT for 2 sec appears safe in patients with PD, but caution should be taken for patients with paroxysmal EEG activity. For this reason, comprehensive screening should include EEG before higher-frequency rTMS is applied. Significance This is the first study to investigate safety of 50 Hz rTMS in humans.
Benninger, David H.; Lomarev, Mikhail; Wassermann, Eric; Lopez, Grisel; Houdayer, Elise; Fasano, Rebecca E.; Dang, Nguyet; Hallett, Mark
Suppression of voluntary motor activity revealed using transcranial magnetic stimulation of the motor cortex in man.
1. Suppression of voluntary muscle activity of hand and arm muscles in response to transcranial magnetic stimulation (TMS) of the motor cortex has been investigated in man. 2. Suppression could be elicited by low levels of TMS without any prior excitatory response. The latency of the suppression was 3-8 ms longer than the excitation observed at a higher stimulus intensity. The duration of the suppression ranged from 8 to 26 ms. 3. A circular stimulating coil was used to determine threshold intensity for excitation and suppression of contraction of thenar muscles in response to TMS at different locations over the motor cortex. The locations for lowest threshold excitation coincided with those for lowest threshold suppression. Suppression was elicited at a lower threshold than excitation at all locations. 4. A figure-of-eight stimulating coil was positioned over the left motor cortex at the lowest threshold point for excitation of the right thenar muscles. The orientation for the lowest threshold excitatory and inhibitory responses was the same for all subjects. That orientation induced a stimulating current travelling in an antero-medial direction. Suppression was invariably elicited at lower thresholds than excitation. 5. When antagonistic muscles (second and third dorsal interosseus) were co-contracted, TMS evoked coincident suppression of voluntary EMG in the two muscles without prior excitation of either muscle. This suggests that the suppression is not mediated via corticospinal activation of spinal interneurones. 6. Test responses to electrical stimulation of the cervical spinal cord were evoked in both relaxed and activated thenar muscles. In the relaxed muscle, prior TMS at an intensity that would suppress voluntary activity failed to influence the test responses, suggesting absence of inhibition at a spinal level. However, in the activated muscle, prior TMS could reduce the test response. This may be explained by disfacilitation of motoneurones due to inhibition of corticospinal output. 7. We propose that suppression of voluntary muscle activity by TMS is due in large part to activation of a mechanism within the motor cortex that reduces the corticospinal output to the muscle. It is concluded that TMS evokes excitation and inhibition via neuronal structures lying close to one another and having similar orientations.
Davey, N J; Romaiguere, P; Maskill, D W; Ellaway, P H
Measures of cortical inhibition by paired-pulse transcranial magnetic stimulation in anesthetized rats.
Paired-pulse transcranial magnetic stimulation (ppTMS) is a noninvasive method to measure cortical inhibition in vivo. Long interpulse interval (50-500 ms) ppTMS (LI-ppTMS) provokes intracortical inhibitory circuits and can reveal pathologically impaired cortical inhibition in disorders such as epilepsy. Adaptation of ppTMS protocols to rodent disease models is highly desirable to facilitate basic and translational research. We previously adapted single-pulse TMS (spTMS) methods to rats, but ppTMS has yet to be applied. Specifically, whether ppTMS elicits an inhibitory response in rodents is unknown. ppTMS in rats also requires anesthesia, a setting under which the preservation of these measures is undetermined. We therefore tested, in anesthetized rats, whether anesthetic choice affects spTMS-motor-evoked potentials (MEPs), LI-ppTMS in rats, as in humans, elicits intracortical inhibition of the MEP, and rat LI-ppTMS inhibition is acutely impaired in a seizure model. Rats were anesthetized with pentobarbital (PB) or ketamine-atropine-xylazine (KAX) and stimulated unilaterally over the motor cortex while recording bilateral brachioradialis MEPs. LI-ppTMS was applied analogous to human long interval intracortical inhibition (LICI) protocols, and acute changes in inhibition were evaluated following injection of the convulsant pentylenetetrazole (PTZ). We find that spTMS-evoked MEPs were reliably present under either anesthetic, and that LI-ppTMS elicits inhibition of the conditioned MEP in rats, similar to human LICI, by as much as 58 � 12 and 71 � 11% under PB and KAX anesthesia, respectively. LI-ppTMS inhibition was reduced to as much as 53% of saline controls following PTZ injection, while spTMS-derived measures of corticospinal excitability were unchanged. Our data show that regional inhibition, similar to human LICI, is present in rats, can be elicited under PB or KAX anesthesia, and is reduced following convulsant administration. These results suggest a potential for LI-ppTMS as a biomarker of impaired cortical inhibition in murine disease models. PMID:21160011
Vahabzadeh-Hagh, Andrew M; Muller, Paul A; Pascual-Leone, Alvaro; Jensen, Frances E; Rotenberg, Alexander
Short communication The effect of repetitive transcranial magnetic stimulation on long-term potentiation in rat hippocampus depends on stimulus intensity
We investigated the effect of repetitive transcranial magnetic stimulation (rTMS) on long-term potentiation (LTP) in the rat hippocampus. Rats were magnetically stimulated at a rate of 1000 pulses\\/day for 7 days by a round coil, in which the peak magnetic fields at the center of the coil were 0.75 and 1.00 T. LTP enhancement was observed only in the 0.75-T
Abnormal excitability of the corticospinal pathway in patients with amyotrophic lateral sclerosis: a single motor unit study using transcranial magnetic stimulation
The pathophysiology of corticospinal tract degeneration in amyotrophic lateral sclerosis (ALS) was investigated by studying the effect of transcranial magnetic stimulation on discharge characteristics of single motor units during voluntary activation. The motor units were recorded from the first dorsal interosseus muscles of 12 patients with ALS, 14 healthy subjects, 12 patients with upper motor neuron lesions and 9 with
N. Kohara; R. Kaji; Y. Kojima; K. R. Mills; H. Fujii; T. Hamano; J. Kimura; N. Takamatsu; T. Uchiyama
Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Poststroke Patients with Upper Limb Hemiparesis: Preliminary Study of a 15-Day Protocol
The purpose of the study was to determine the safety and feasibility of a 15-day protocol of low-frequency repetitive transcranial magnetic stimulation (rTMS) combined with intensive occupational therapy (OT) on motor function and spasticity in hemiparetic upper limbs in poststroke patients. Fifteen poststroke patients (age at study entry 55 [plus�
Kakuda, Wataru; Abo, Masahiro; Kobayashi, Kazushige; Momosaki, Ryo; Yokoi, Aki; Fukuda, Akiko; Ishikawa, Atsushi; Ito, Hiroshi; Tominaga, Ayumi
Functional Representation of Living and Nonliving Domains across the Cerebral Hemispheres: A Combined Event-related Potential\\/Transcranial Magnetic Stimulation Study
Transcranial magnetic stimulation (TMS) over the left hemisphere has been shown to disrupt semantic processing but, to date, there has been no direct demonstration of the electrophysiological correlates of this interference. To gain insight into the neural basis of semantic systems, and in particular, study the temporal and functional organization of object categorization processing, we combined repetitive TMS (rTMS) and
Giorgio Fuggetta; Silvia Rizzo; Gorana Pobric; Michal Lavidor; Vincent Walsh
Unilateral left prefrontal transcranial magnetic stimulation (TMS) produces intensity-dependent bilateral effects as measured by interleaved BOLD fMRI
Transcranial magnetic stimulation (TMS) administered over the prefrontal cortex has been shown to subtly influence neuropsychological tasks, and has antidepressant effects when applied daily for several weeks. Prefrontal TMS does not, however, produce an immediate easily observable effect, making it hard to determine if one has stimulated the cortex. Most prefrontal TMS studies have stimulated using intensity relative to the
Ziad Nahas; Mikhail Lomarev; Donna R. Roberts; Ananda Shastri; Jeffrey P. Lorberbaum; Charlotte Teneback; Kathleen McConnell; Diana J. Vincent; Xingbao Li; Mark S. George; Daryl E. Bohning
Neurophysiology and Neuroanatomy of Reflexive and Volitional Saccades as Revealed by Lesion Studies with Neurological Patients and Transcranial Magnetic Stimulation (TMS)
This review discusses the neurophysiology and neuroanatomy of the cortical control of reflexive and volitional saccades in humans. The main focus is on classical lesion studies and studies using the interference method of transcranial magnetic stimulation (TMS). To understand the behavioural function of a region, it is essential to assess�
Muri, Rene M.; Nyffeler, Thomas
Simulating Transcranial Magnetic Stimulation during PET with a Large-Scale Neural Network Model of the Prefrontal Cortex and the Visual System
Transcranial magnetic stimulation (TMS) exerts both excitatory and inhibitory effects on the stimulated neural tissue, although little is known about the neurobiological mechanisms by which it influences neuronal function. TMS has been used in conjunction with PET to examine interregional connectivity of human cerebral cortex. To help understand how TMS affects neuronal function, and how these effects are manifested during
F. T. Husain; G. Nandipati; A. R. Braun; L. G. Cohen; M. A. Tagamets; B. Horwitz
Post-stroke reorganization of brain motor output to the hand: a 2�4 month follow-up with focal magnetic transcranial stimulation
Focal transcranial magnetic stimulation (TCS) was employed for the representation of the motor cortex in a population of 18 patients to investigate the functional properties of hand motor areas 2�4 months after a monohemispheric stroke. Eleven sites were stimulated to elicit motor evoked potentials (MEPs) in abductor digiti minimi muscle after TCS of affected (AH) and unaffected (UH) hemispheres; recording
P Cicinelli; R Traversa; P. M Rossini
Hand motor cortex activation in a patient with congenital mirror movements: a study of the silent period following focal transcranial magnetic stimulation
Motor evoked potentials (MEPs) to focal transcranial magnetic stimulation (TMS) have demonstrated that abnormal ipsilateral corticospinal projections are active in patients with congenital mirror movements. In addition, movement-related potentials and PET suggest that an abnormal pattern of motor cortex activation could be associated with an anomaly of the corticospinal tracts. In the present study the silent period (SP) following focal
M. Cincotta; S. Lori; P. F. Gangemi; F. Barontini; A. Ragazzoni
Design of a placebo-controlled, randomized study of the efficacy of repetitive transcranial magnetic stimulation for the treatment of chronic tinnitus
BACKGROUND: Chronic tinnitus is a frequent condition, which can have enormous impact on patient's life and which is very difficult to treat. Accumulating data indicate that chronic tinnitus is related to dysfunctional neuronal activity in the central nervous system. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method which allows to focally modulate neuronal activity. An increasing amount of studies
Michael Landgrebe; Harald Binder; Michael Koller; Yvonne Eberl; Tobias Kleinjung; Peter Eichhammer; Erika Graf; Goeran Hajak; Berthold Langguth
Central Cord Syndrome of Cervical Spinal Cord Injury: Widespread Changes in Muscle Recruitment Studied by Voluntary Contractions and Transcranial Magnetic Stimulation
Muscle recruitment after central cord syndrome (CCS), a cervical spinal cord injury leading to a weaker motor function in the upper limbs versus the lower limbs, was examined in 14 individuals by means of voluntary muscle contractions and transcranial magnetic stimulation (TMS). Previously obtained data from able-bodied (AB) and non-CCS spinal cord injured subjects were used for comparison. Surface EMG
Natalia Alexeeva; James G. Broton; Sonia Suys; Blair Calancie
Localization of the motor hand area using transcranial magnetic stimulation and functional magnetic resonance imaging
Objective: The anatomical location of the motor area of the hand may be revealed using functional magnetic resonance imaging (fMRI). The motor cortex representation of the intrinsic hand muscles consists of a knob-like structure. This is omega- or epsilon-shaped in the axial plane and hook-shaped in the sagittal plane. As this knob lies on the surface of the brain, it
B Boroojerdi; H Foltys; T Krings; U Spetzger; A Thron; R T�pper
An integrated computer-controlled system for assisting researchers in cortical excitability studies by using transcranial magnetic stimulation.
Transcranial magnetic stimulation (TMS) is the most important technique currently available to study cortical excitability. Additionally, TMS can be used for therapeutic and rehabilitation purposes, replacing the more painful transcranial electric stimulation (TES). In this paper we present an innovative and easy-to-use tool that enables neuroscientists to design, carry out and analyze scientific studies based on TMS experiments for both diagnostic and research purposes, assisting them not only in the practicalities of administering the TMS but also in each step of the entire study's workflow. One important aspect of this tool is that it allows neuroscientists to specify research designs at will, enabling them to define any parameter of a TMS study starting from data acquisition and sample group definition to automated statistical data analysis and RDF data storage. It also supports the diagnosing process by using on-line support vector machines able to learn incrementally from the diseases instances that are continuously added into the system. The proposed system is a neuroscientist-centred tool where the protocols being followed in TMS studies are made explicit, leaving to the users flexibility in exploring and sharing the results, and providing assistance in managing the complexity of the final diagnosis. This type of tool can make the results of medical experiments more easily exploitable, thus accelerating scientific progress. PMID:22172294
Giordano, D; Kavasidis, I; Spampinato, C; Bella, R; Pennisi, G; Pennisi, M
Effect of Transcranial Magnetic Stimulation on Short and Long-Term Memory in Healthy Subjects and Patients with Parkinson�s Disease
The effect of transcranial magnetic stimulation (TMS) of the right and the left frontotemporal areas on the short- and long-term verbal memory was studied in healthy subjects and patients with Parkinson�s disease. TMS with a magnetic induction of more than 1.2 T at 10 Hz was found to affect the short-term memory when applied to the left frontotemporal area and
R. F. Gimranov; E. A. Mal�tseva
Neuroendocrine and Behavioral Effects of Repetitive Transcranial Magnetic Stimulation in a Psychopathological Animal Model Are Suggestive of Antidepressant-like Effects
The neuroendocrine and behavioral effects of repetitive transcranial magnetic stimulation (rTMS) were investigated in two rat lines selectively bred for high and low anxiety-related behavior. The stimulation parameters were adjusted according to the results of accurate computer-assisted and magnetic resonance imaging-based reconstructions of the current density distributions induced by rTMS in the rat and human brain, ensuring comparable stimulation patterns
Martin E. Keck; Tobias Welt; Anke Post; Marianne B. M�ller; Nicola Toschi; Alexandra Wigger; Rainer Landgraf; Florian Holsboer; Mario Engelmann
A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system
Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding. There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self) and allocentric (i.e., other) viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity), there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation.
Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.
Lack of effects of low frequency repetitive transcranial magnetic stimulation on alpha rhythm phase synchronization in migraine patients.
The study aimed to test the modulation induced by 1 Hz repetitive Transcranial Magnetic Stimulation (rTMS) of the occipital cortex on the alpha phase synchronization under repetitive flash stimuli in 15 migraine without aura patients compared to 10 controls. The EEG was recorded by 7 channels, while flash stimuli were delivered at 9, 18, 21 and 24 Hz in basal, rTMS (15 min of 1 Hz stimulation of the occipital cortex) and sham conditions. Migraine patients displayed increased alpha-band phase synchronization under visual stimulation, while an overall desynchronizing effect was evident in controls. The rTMS resulted in a slight increase of synchronization index in migraine patients, which did not cause significant differences in respect to the basal and sham conditions. The synchronizing-desynchronizing changes of alpha rhythm under repetitive flash stimulation, seem independent from the state of occipital cortex excitability. Other mechanisms beyond cortical excitability may contribute to explain migraine pathogenesis. PMID:21075171
de Tommaso, Marina; Stramaglia, Sebastiano; Brighina, Filippo; Fierro, Brigida; Francesco, Vito Devito; Todarello, Orlando; Serpino, Claudia; Pellicoro, M
Surgery for a giant arteriovenous malformation without motor deterioration: preoperative transcranial magnetic stimulation in a non-cooperative patient.
Transcranial magnetic stimulation (TMS) is a noninvasive activation method that is increasingly used for motor mapping. Preoperative functional mapping in vascular surgery is not routinely performed; however, in cases of high-grade arteriovenous malformations (AVMs), it could play a role in preoperative decision making. A 16-year-old male was suffering from a giant, right-sided insular, Spetzler-Martin Grade V AVM. This patient's history included 3 hemorrhagic strokes in the past 3 years, resulting in Medical Research Council Grade 2-3 (proximal) and 2-4 (distal) paresis of the left side of the body and hydrocephalus requiring a ventriculoperitoneal shunt. Preoperative TMS showed absent contralateral innervation of the remaining left-sided motor functions. Subsequently, the AVM was completely resected without any postoperative increase of the left-sided paresis. This case shows that TMS can support decision making in AVM treatment by mapping motor functions. PMID:24866824
Kronenburg, Annick; van Doormaal, Tristan; van Eijsden, Pieter; van der Zwan, Albert; Leijten, Frans; Han, Kuo Sen
Listening to speech recruits specific tongue motor synergies as revealed by transcranial magnetic stimulation and tissue-Doppler ultrasound imaging.
The activation of listener's motor system during speech processing was first demonstrated by the enhancement of electromyographic tongue potentials as evoked by single-pulse transcranial magnetic stimulation (TMS) over tongue motor cortex. This technique is, however, technically challenging and enables only a rather coarse measurement of this motor mirroring. Here, we applied TMS to listeners' tongue motor area in association with ultrasound tissue Doppler imaging to describe fine-grained tongue kinematic synergies evoked by passive listening to speech. Subjects listened to syllables requiring different patterns of dorso-ventral and antero-posterior movements (/ki/, /ko/, /ti/, /to/). Results show that passive listening to speech sounds evokes a pattern of motor synergies mirroring those occurring during speech production. Moreover, mirror motor synergies were more evident in those subjects showing good performances in discriminating speech in noise demonstrating a role of the speech-related mirror system in feed-forward processing the speaker's ongoing motor plan. PMID:24778384
D'Ausilio, A; Maffongelli, L; Bartoli, E; Campanella, M; Ferrari, E; Berry, J; Fadiga, L
Changes in mood and hormone levels after rapid-rate transcranial magnetic stimulation (rTMS) of the prefrontal cortex.
Rapid-rate transcranial magnetic stimulation (rTMS) was administered to 10 healthy volunteers on different days over the right or left prefrontal cortex, midfrontal cortex, occipital cortex, or cerebellum. Mood (self-rated), reaction time, and hormone levels were serially measured. Consistent with a previous study, comparison of hemispheres revealed significant associations with decreased happiness after left prefrontal rTMS and decreased sadness after right prefrontal rTMS. Stimulation of all three prefrontal regions, but not the occipital or cerebellar regions, was associated with increases in serum thyroid-stimulating hormone. There was no effect on serum prolactin. rTMS applied to prefrontal cortex is safe and well tolerated and produces regionally and laterally specific changes in mood and neuroendocrine measures in healthy adults. rTMS is a promising tool for investigating prefrontal cortex functions. PMID:9081553
George, M S; Wassermann, E M; Williams, W A; Steppel, J; Pascual-Leone, A; Basser, P; Hallett, M; Post, R M
Safety, tolerability and preliminary evidence for antidepressant efficacy of theta-burst transcranial magnetic stimulation in patients with major depression.
The aim of this open study was to evaluate the safety and tolerability of theta-burst transcranial magnetic stimulation (TBS) and to assess preliminarily its therapeutic efficacy in patients with major depression. A total of 33 patients were assigned to receive one of four TBS protocols for 10 consecutive work days. TBS consisted of triple-pulse 50-Hz bursts given at a rate of 5 Hz to the left or right dorsolateral prefrontal cortex at different stimulation parameters. Severity of depression was assessed by the Hamilton Depression Rating Scale. Our results indicate that TBS as applied in this study is safe and well tolerated in depressed patients and seems to have antidepressant properties. Increase of stimulation parameters is not associated with more side-effects and adds to its therapeutic effect. PMID:20128955
Chistyakov, Andrei V; Rubicsek, Odil; Kaplan, Boris; Zaaroor, Menashe; Klein, Ehud
Novel Therapeutic Strategies for Alcohol and Drug Addiction: Focus on GABA, Ion Channels and Transcranial Magnetic Stimulation
Drug addiction represents a major social problem where addicts and alcoholics continue to seek and take drugs despite adverse social, personal, emotional, and legal consequences. A number of pharmacological compounds have been tested in human addicts with the goal of reducing the level or frequency of intake, but these pharmacotherapies have often been of only moderate efficacy or act in a sub-population of humans. Thus, there is a tremendous need for new therapeutic interventions to treat addiction. Here, we review recent interesting studies focusing on gamma-aminobutyric acid receptors, voltage-gated ion channels, and transcranial magnetic stimulation. Some of these treatments show considerable promise to reduce addictive behaviors, or the early clinical studies or pre-clinical rationale suggest that a promising avenue could be developed. Thus, it is likely that within a decade or so, we could have important new and effective treatments to achieve the goal of reducing the burden of human addiction and alcoholism.
Addolorato, Giovanni; Leggio, Lorenzo; Hopf, F Woodward; Diana, Marco; Bonci, Antonello
A neuronal network model for simulating the effects of repetitive transcranial magnetic stimulation on local field potential power spectra.
Repetitive transcranial magnetic stimulation (rTMS) holds promise as a non-invasive therapy for the treatment of neurological disorders such as depression, schizophrenia, tinnitus, and epilepsy. Complex interdependencies between stimulus duration, frequency and intensity obscure the exact effects of rTMS stimulation on neural activity in the cortex, making evaluation of and comparison between rTMS studies difficult. To explain the influence of rTMS on neural activity (e.g. in the motor cortex), we use a neuronal network model. The results demonstrate that the model adequately explains experimentally observed short term effects of rTMS on the band power in common frequency bands used in electroencephalography (EEG). We show that the equivalent local field potential (eLFP) band power depends on stimulation intensity rather than on stimulation frequency. Additionally, our model resolves contradictions in experiments. PMID:23145082
Bey, Alina; Leue, Stefan; Wienbruch, Christian
Preoperative multimodal motor mapping: a comparison of magnetoencephalography imaging, navigated transcranial magnetic stimulation, and direct cortical stimulation
Object Direct cortical stimulation (DCS) is the gold-standard technique for motor mapping during craniotomy. However, preoperative noninvasive motor mapping is becoming increasingly accurate. Two such noninvasive modalities are navigated transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG) imaging. While MEG imaging has already been extensively validated as an accurate modality of noninvasive motor mapping, TMS is less well studied. In this study, the authors compared the accuracy of TMS to both DCS and MEG imaging. Methods Patients with tumors in proximity to primary motor cortex underwent preoperative TMS and MEG imaging for motor mapping. The patients subsequently underwent motor mapping via intraoperative DCS. The loci of maximal response were recorded from each modality and compared. Motor strength was assessed at 3 months postoperatively. Results Transcranial magnetic stimulation and MEG imaging were performed on 24 patients. Intraoperative DCS yielded 8 positive motor sites in 5 patients. The median distance � SEM between TMS and DCS motor sites was 2.13 � 0.29 mm, and between TMS and MEG imaging motor sites was 4.71 � 1.08 mm. In no patients did DCS motor mapping reveal a motor site that was unrecognized by TMS. Three of 24 patients developed new, early neurological deficit in the form of upper-extremity paresis. At the 3-month follow-up evaluation, 2 of these patients were significantly improved, experiencing difficulty only with fine motor tasks; the remaining patient had improvement to 4/5 strength. There were no deaths over the course of the study. Conclusions Maps of the motor system generated with TMS correlate well with those generated by both MEG imaging and DCS. Negative TMS mapping also correlates with negative DCS mapping. Navigated TMS is an accurate modality for noninvasively generating preoperative motor maps.
Tarapore, Phiroz E.; Tate, Matthew C.; Findlay, Anne M.; Honma, Susanne M.; Mizuiri, Danielle; Berger, Mitchel S.; Nagarajan, Srikantan S.
On the Magnetic Susceptiability Anisotropy of Deep-Sea Sediment.
Susceptibility anisotropies in the form of vertically prolate ellipsoids have been reported in many deep-sea sediment cores. The results of the present investigation suggest that these anisotropies may not describe the original magnetic fabric of deep-sea...
D. V. Kent W. Lowrie
Disturbance of visual search by stimulating to posterior parietal cortex in the brain using transcranial magnetic stimulation
In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the ``easy feature task,'' the ``hard feature task,'' and the ``conjunction task.'' To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.
Iramina, Keiji; Ge, Sheng; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo
Sensed presence and mystical experiences are predicted by suggestibility, not by the application of transcranial weak complex magnetic fields.
Transcranial magnetic stimulation (TMS) with weak (micro Tesla) complex waveform fields have been claimed to evoke the sensed presence of a sentient being in up to 80% in the general population. These findings have had a questionable neurophysiological foundation as the fields are approximately six orders of magnitude weaker than ordinary TMS fields. Also, no independent replication has been reported. To replicate and extend previous findings, we performed a double-blind experiment (N=89), with a sham-field control group. Personality characteristics indicating suggestibility (absorption, signs of abnormal temporal lobe activity, and a "new age"-lifestyle orientation) were used as predictors. Sensed presence, mystical, and other somatosensory experiences previously reported from the magnetic field stimulation were outcome measures. We found no evidence for any effects of the magnetic fields, neither in the entire group, nor in individuals high in suggestibility. Because the personality characteristics significantly predicted outcomes, suggestibility may account for previously reported effects. Our results strongly question the earlier claims of experiential effects of weak magnetic fields. PMID:15849873
Granqvist, Pehr; Fredrikson, Mats; Unge, Patrik; Hagenfeldt, Andrea; Valind, Sven; Larhammar, Dan; Larsson, Marcus
The Effect of Variation in Permittivity of Different Tissues on Induced Electric Field in the Brain during Transcranial Magnetic Stimulation
Estimation of electric field in the brain during Transcranial Magnetic Stimulation (TMS) requires knowledge of the electric property of brain tissue. Grey and white matters have unusually high relative permittivities of � 10^6 at low frequencies. However, relative permittivity of cerebrospinal fluid is � 10^2. With such a variation it is necessary to consider the effect of boundaries. A model consisting of 2 hemispheres was used in the model with the properties of one hemisphere kept constant at ?1=0.1Sm-1 and ?r1= 10 while the properties of the second hemisphere were changed kept at ?2=0.1Sm-1 to 2Sm-1 and ?r2= 10^2 to 10^5. A 70 mm diameter double coil was used as the source of the magnetic field. The amplitude of the current in the coil was 5488 A at a frequency of 2.9 kHz. The results show that the electric field, E induced during magnetic stimulation is independent of the relative permittivity, ?r and varies with the conductivity. Thus the variation in E, calculated with homogeneous and heterogeneous head models was due to variation in conductivity of the tissues and not due to variation in permittivities.
Hadimani, Ravi L.; Porzig, Konstantin; Crowther, Lawrence J.; Brauer, Hartmut; Toepfer, Hannes; Jiles, David C.
Venus Deep Nightside Magnetic Fields Revisited
We reexamined the near-Venus deep nightside magnetic fields observed by the Pioneer Venus Orbiter(PVO) over two decades ago. This analysis was in part inspired by recent discussions of the possibilities of identifying a weak planetary dynamo or remanent magnetic field, and in part by the availability of numerical simulations of weak field plasma interactions using the BATS-R-US MHD code. The data were first scrutinized for statistically significant regions of radial field in the near-midnight low altitude wake from the prime mission periapsis of ~150km up to about 450 km. Radial field 'maps' were constructed for a range of altitudes in both solar wind interaction and planetary geographical coordinate systems. The results suggested the presence of weak radial fields above ~250km that show a persistent North-South sign bias. This behavior is not seen at the lowest altitudes probed, and is present regardless of the interplanetary magnetic field sector. The MHD simulations provided basic pictures of what might be expected for a hypothetical planet with a weak but still detectable dipole field that is comparable to the solar wind interaction-related draped interplanetary field. These show similar tendencies, illustrating that models are essential to the interpretation of potential weak intrinsic field signatures at planets such as Venus. Further modeling specific to Venus is needed to make further progress.
Villarreal, M. N.; Luhmann, J. G.; Ma, Y.; Russell, C. T.; Wei, H.; Zhang, T.
Treatment of auditory verbal hallucinations with transcranial magnetic stimulation in a patient with psychotic major depression: One-year follow-up
Auditory verbal hallucinations (AVH) in patients with schizophrenia can respond to repetitive transcranial magnetic stimulation (TMS). We report the therapeutic utility of rTMS in a 48-year-old patient with a 20-year history of severe depression (five suicidal gestures and previous failure of ECT) and internal AVH. First, 20 Hz rTMS to the left prefrontal cortex for 3 weeks significantly improved depression
Catarina Freitas; Chester Pearlman; Alvaro Pascual-Leone
The role of dorsal premotor area in reaction task: comparing the �virtual lesion� effect of paired pulse or theta burst transcranial magnetic stimulation
We compared the effect on reaction times of transient interference with function of the dorsal premotor cortex (PMd) using\\u000a a pair (25-ms interval) of transcranial magnetic stimulation (TMS) pulses with long-term interference produced by a new repetitive\\u000a TMS paradigm known as �theta burst stimulation� (TBS). Pairs of TMS pulses over left PMd increased choice but not simple reaction\\u000a times of
Hitoshi Mochizuki; Michele Franca; Ying-Zu Huang; John C. Rothwell
Rapid-rate transcranial magnetic stimulation of animal auditory cortex impairs short-term but not long-term memory formation
Bilateral rapid-rate transcranial magnetic stimulation (rTMS) of gerbil auditory cortex with a miniature coil device was used to study short-term and long-term effects on discrimination learning of frequency-modulated tones. We found previously that directional discrimination of frequency modulation (rising vs. falling) relies on auditory cortex processing and that formation of its memory depends on local protein synthesis. Here we show
Hong Wang; Xu Wang; Wolfram Wetzel; Henning Scheich
Beneficial effect of repetitive transcranial magnetic stimulation combined with cognitive training for the treatment of Alzheimer�s disease: a proof of concept study
The current drug treatment for Alzheimer�s disease (AD) is only partially and temporary effective. Transcranial magnetic stimulation\\u000a (TMS) is a non-invasive technique that generates an electric current inducing modulation in cortical excitability. In addition,\\u000a cognitive training (COG) may improve cognitive functions in AD. Our aim was to treat AD patients combining high-frequency\\u000a repetitive TMS interlaced with COG (rTMS-COG). Eight patients
Jonathan Bentwich; Evgenia Dobronevsky; Sergio Aichenbaum; Ran Shorer; Ruth Peretz; Michael Khaigrekht; Revital Gandelman Marton; Jose M. Rabey
High and low-frequency repetitive transcranial magnetic stimulation differentially activates c-Fos and zif268 protein expression in the rat brain
Repetitive transcranial magnetic stimulation (rTMS) has been shown to alter cortical excitability depending on the stimulus-frequency\\u000a used, with high frequency (5�Hz and higher) increasing it but low frequency (usually 1�Hz or lower) reducing it. To determine\\u000a the efficiency of different rTMS protocols in inducing cortical network activity, we tested the acute effect of one low-frequency\\u000a rTMS protocol (1�Hz) and two
Selcen Aydin-Abidin; J�rn Trippe; Klaus Funke; Ulf T. Eysel; Alia Benali
Repetitive transcranial magnetic stimulation (rTMS) in pharmacotherapy-refractory major depression: comparative study of fast, slow and sham rTMS
In previous studies, fast repetitive transcranial magnetic stimulation (rTMS) with a frequency >1 Hz demonstrated substantial antidepressant effects compared to sham rTMS. However, it is not clear whether fast rTMS is superior to slow rTMS (frequency ?1 Hz) which is safe at therapeutically promising higher intensities. The aim of this double-blind study was to compare the action of fast, slow
Frank Padberg; Peter Zwanzger; Heike Thoma; Norbert Kathmann; Clemenz Haag; Benjamin D. Greenberg; Harald Hampel; Hans-J�rgen M�ller
Repetitive transcranial magnetic stimulation is as effective as electroconvulsive therapy in the treatment of nondelusional major depressive disorder: an open study
%Background: Repetitive transcranial magnetic stimulation (rTMS), a new method for the stimulation of the central nervous system, is being proposed as a potential new treatment in patients with major depressive disorder (MDD). We tested the hypothesis that rTMS would be as effective as electroconvulsive therapy (ECT) in patients with MDD.Methods: Forty patients with MDD referred for ECT were randomly assigned
Leon Grunhaus; Pinhas N. Dannon; Shaul Schreiber; Ornah H. Dolberg; Revital Amiaz; Reuven Ziv; Eli Lefkifker
Opposite impact on 14 C-2-deoxyglucose brain metabolism following patterns of high and low frequency repetitive transcranial magnetic stimulation in the posterior parietal cortex
Repetitive transcranial magnetic stimulation (rTMS) appears capable of modulating human cortical excitability beyond the duration\\u000a of the stimulation train. However, the basis and extent of this �off-line� modulation remains unknown. In a group of anesthetized\\u000a cats, we applied patterns of real or sham focal rTMS to the visuo-parietal cortex (VP) at high (HF) or low (LF) frequency\\u000a and recorded brain
Antoni Valero-Cabr�; Bertram R. Payne; Alvaro Pascual-Leone
Effect of high frequency repetitive transcranial magnetic stimulation on reaction time, clinical features and cognitive functions in patients with Parkinson�s disease
The aim of the present study was to investigate the effects of one session of high-frequency repetitive transcranial magnetic\\u000a stimulation (rTMS) applied over the left dorsal premotor cortex (PMd) and left dorsolateral prefrontal cortex (DLPFC) on choice\\u000a reaction time in a noise-compatibility task, and cognitive functions in patients with Parkinson�s disease (PD). Clinical motor\\u000a symptoms of PD were assessed as
Silvie Sedl�?kov�; Irena Rektorov�; Hana Srovnalov�; Ivan Rektor
Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomised, double-blind, parallel-group, sham-controlled trial
Background Preliminary work suggests that single-pulse transcranial magnetic stimulation (sTMS) could be effective as a treatment for migraine. We aimed to assess the efficacy and safety of a new portable sTMS device for acute treatment of migraine with aura. Methods We undertook a randomised, double-blind, parallel-group, two-phase, sham-controlled study at 18 centres in the USA. 267 adults aged 18-68 years
Richard B Lipton; David W Dodick; Stephen D Silberstein; Joel R Saper; Sheena K Aurora; Starr H Pearlman; Robert E Fischell; Patricia L Ruppel; Peter J Goadsby
High-frequency transcranial magnetic stimulation of the supplementary motor area reduces bimanual coupling during anti-phase but not in-phase movements
Previous electrophysiological and neuroimaging studies have provided evidence that the supplementary motor area (SMA) has\\u000a an important role in the control of bimanual coordination. The present experiment investigated the effects of high-frequency\\u000a repetitive transcranial magnetic stimulation (rTMS) over the SMA region on kinematic variables during cyclical bimanual coordination,\\u000a with a particular focus on the quality of coordination. Subjects performed metronome-paced
Maarten Steyvers; Seiji Etoh; Dieter Sauner; Oron Levin; Hartwig R. Siebner; Stephan P. Swinnen; John C. Rothwell
Effects of a 2- to 4-week course of repetitive transcranial magnetic stimulation (rTMS) on neuropsychologic functioning, electroencephalogram, and auditory threshold in depressed patients
Background: The safety of repetitive transcranial magnetic stimulation (rTMS) has only previously been formally studied in volunteers receiving a single session of stimulation or in a small number of depressed subjects receiving a 2-week treatment course. This study examined safety issues in depressed subjects receiving up to 4 weeks of rTMS. Efficacy results from this study have been previously reported.Methods:
Colleen Loo; Perminder Sachdev; Hamada Elsayed; Benjamin McDarmont; Philip Mitchell; Monica Wilkinson; Gordon Parker; Simon Gandevia
Measuring and manipulating brain connectivity with resting state functional connectivity magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS).
Both resting state functional magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS) are increasingly popular techniques that can be used to non-invasively measure brain connectivity in human subjects. TMS shows additional promise as a method to manipulate brain connectivity. In this review we discuss how these two complimentary tools can be combined to optimally study brain connectivity and manipulate distributed brain networks. Important clinical applications include using resting state fcMRI to guide target selection for TMS and using TMS to modulate pathological network interactions identified with resting state fcMRI. The combination of TMS and resting state fcMRI has the potential to accelerate the translation of both techniques into the clinical realm and promises a new approach to the diagnosis and treatment of neurological and psychiatric diseases that demonstrate network pathology. PMID:22465297
Fox, Michael D; Halko, Mark A; Eldaief, Mark C; Pascual-Leone, Alvaro
Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex. In TMS with a figure-of-eight coil, the induced electric field elicited by the pulsed magnetic fields is gathered beneath the center of the figure-of-eight coil, so the point on the cortex beneath the center of the figure-of-eight coil has been regarded as a stimulating site conventionally. However, the stimulating point determined in this way is not supposed to be plausible because electric field induced in TMS is dispersed over the brain vectorially. The present study proposed the novel method for the accurate estimation of stimulating points of the cortex in TMS. In our proposed method, the cortical structure and property of neural excitation in magnetic nerve stimulation were taken into account. The basic unit of the cerebral cortex is the cylindrical column containing pyramidal neurons perpendicular to the cortical surface, and neural excitation in the magnetic nerve stimulation is determined by the spatial derivative of the electric field parallel to the cablelike neuron such as a pyramidal neuron. According to these understandings, the relative intensity of nerve stimulation in TMS corresponds to the strength of the component of the induced electrical field perpendicular to the cortical surface. We realized the method for the estimation of stimulating sites of the cortex in TMS by using this principle. The component of the electric field perpendicular to the cortical surface at each pixel of magnetic resonance imaging was obtained with computation of the dot product of the electric field and the unit vector perpendicular to the cortex surface. The strength of the component of the electric field perpendicular to the cortical surface was regarded as the stimulating strength at each pixel of the cortical surface in TMS. We conducted the experiments of TMS to confirm the validity of this method. The cortex sites, which innervate muscles of the upper limb, were successfully delineated in primary motor area by the proposed method.
Hiwaki, Osamu; Inoue, Tomonori
An efficient 3-D eddy-current solver using an independent impedance method for transcranial magnetic stimulation.
In many important bioelectromagnetic problem settings, eddy-current simulations are required. Examples are the reduction of eddy-current artifacts in magnetic resonance imaging and techniques, whereby the eddy currents interact with the biological system, like the alteration of the neurophysiology due to transcranial magnetic stimulation (TMS). TMS has become an important tool for the diagnosis and treatment of neurological diseases and psychiatric disorders. A widely applied method for simulating the eddy currents is the impedance method (IM). However, this method has to contend with an ill conditioned problem and consequently a long convergence time. When dealing with optimal design problems and sensitivity control, the convergence rate becomes even more crucial since the eddy-current solver needs to be evaluated in an iterative loop. Therefore, we introduce an independent IM (IIM), which improves the conditionality and speeds up the numerical convergence. This paper shows how IIM is based on IM and what are the advantages. Moreover, the method is applied to the efficient simulation of TMS. The proposed IIM achieves superior convergence properties with high time efficiency, compared to the traditional IM and is therefore a useful tool for accurate and fast TMS simulations. PMID:20959261
De Geeter, Nele; Crevecoeur, Guillaume; Dupre, Luc
Relationship between transcranial magnetic stimulation measures of intracortical inhibition and spectroscopy measures of GABA and glutamate+glutamine
Transcranial magnetic stimulation (TMS) can provide an index of intracortical excitability/inhibition balance. However, the neurochemical substrate of these measures remains unclear. Pharmacological studies suggest the involvement of GABAA and GABAB receptors in TMS protocols aimed at measuring intracortical inhibition, but this link remains inferential. Proton magnetic resonance spectroscopy (1H-MRS) permits measurement of GABA and glutamate + glutamine (Glx) concentrations in the human brain and might help in the direct empirical assessment of the relationship between TMS inhibitory measures and neurotransmitter concentrations. In the present study, MRS-derived relative concentrations of GABA and Glx measured in the left M1 of healthy participants were correlated with TMS measures of intracortical inhibition. Glx levels were found to correlate positively with TMS-induced silent period duration, whereas no correlation was found between GABA concentration and TMS measures. The present data demonstrate that specific TMS measures of intracortical inhibition are linked to shifts in cortical Glx, rather than GABA neurotransmitter levels. Glutamate might specifically interact with GABAB receptors, where higher MRS-derived Glx concentrations seem to be linked to higher levels of receptor activity.
Tremblay, Sara; Beaule, Vincent; Proulx, Sebastien; de Beaumont, Louis; Marjanska, Malgorzata; Doyon, Julien; Pascual-Leone, Alvaro; Lassonde, Maryse
Impact of Repetitive Transcranial Magnetic Stimulation (rTMS) on Brain Functional Marker of Auditory Hallucinations in Schizophrenia Patients
Several cross-sectional functional Magnetic Resonance Imaging (fMRI) studies reported a negative correlation between auditory verbal hallucination (AVH) severity and amplitude of the activations during language tasks. The present study assessed the time course of this correlation and its possible structural underpinnings by combining structural, functional MRI and repetitive Transcranial Magnetic Stimulation (rTMS). Methods: Nine schizophrenia patients with AVH (evaluated with the Auditory Hallucination Rating scale; AHRS) and nine healthy participants underwent two sessions of an fMRI speech listening paradigm. Meanwhile, patients received high frequency (20 Hz) rTMS. Results: Before rTMS, activations were negatively correlated with AHRS in a left posterior superior temporal sulcus (pSTS) cluster, considered henceforward as a functional region of interest (fROI). After rTMS, activations in this fROI no longer correlated with AHRS. This decoupling was explained by a significant decrease of AHRS scores after rTMS that contrasted with a relative stability of cerebral activations. A voxel-based-morphometry analysis evidenced a cluster of the left pSTS where grey matter volume negatively correlated with AHRS before rTMS and positively correlated with activations in the fROI at both sessions. Conclusion: rTMS decreases the severity of AVH leading to modify the functional correlate of AVH underlain by grey matter abnormalities.
Maiza, Olivier; Herve, Pierre-Yve; Etard, Olivier; Razafimandimby, Annick; Montagne-Larmurier, Aurelie; Dollfus, Sonia
Bidirectional effects on interhemispheric resting-state functional connectivity induced by excitatory and inhibitory repetitive transcranial magnetic stimulation.
Several recent studies using functional magnetic resonance imaging (fMRI) have shown that repetitive transcranial magnetic stimulation (rTMS) affects not only brain activity in stimulated regions but also resting-state functional connectivity (RSFC) between the stimulated region and other remote regions. However, these studies have only demonstrated an effect of either excitatory or inhibitory rTMS on RSFC, and have not clearly shown the bidirectional effects of both types of rTMS. Here, we addressed this issue by performing excitatory and inhibitory quadripulse TMS (QPS), which is considered to exert relatively large and long-lasting effects on cortical excitability. We found that excitatory rTMS (QPS with interstimulus intervals of 5 ms) decreased interhemispheric RSFC between bilateral primary motor cortices, whereas inhibitory rTMS (QPS with interstimulus intervals of 50 ms) increased interhemispheric RSFC. The magnitude of these effects on RSFC was significantly correlated with that of rTMS-induced effects on motor evoked potential from the corresponding muscle. The bidirectional effects of QPS were also observed in the stimulation over prefrontal and parietal association areas. These findings provide evidence for the robust bidirectional effects of excitatory and inhibitory rTMSs on RSFC, and raise a possibility that QPS can be a powerful tool to modulate RSFC. PMID:23897535
Watanabe, Takamitsu; Hanajima, Ritsuko; Shirota, Yuichiro; Ohminami, Shinya; Tsutsumi, Ryosuke; Terao, Yasuo; Ugawa, Yoshikazu; Hirose, Satoshi; Miyashita, Yasushi; Konishi, Seiki; Kunimatsu, Akira; Ohtomo, Kuni
Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex.
Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects. PMID:23757042
Mesquita, Rickson C; Faseyitan, Olufunsho K; Turkeltaub, Peter E; Buckley, Erin M; Thomas, Amy; Kim, Meeri N; Durduran, Turgut; Greenberg, Joel H; Detre, John A; Yodh, Arjun G; Hamilton, Roy H
The relationship between brain oscillatory activity and therapeutic effectiveness of transcranial magnetic stimulation in the treatment of major depressive disorder
Major depressive disorder (MDD) is marked by disturbances in brain functional connectivity. This connectivity is modulated by rhythmic oscillations of brain electrical activity, which enable coordinated functions across brain regions. Oscillatory activity plays a central role in regulating thinking and memory, mood, cerebral blood flow, and neurotransmitter levels, and restoration of normal oscillatory patterns is associated with effective treatment of MDD. Repetitive transcranial magnetic stimulation (rTMS) is a robust treatment for MDD, but the mechanism of action (MOA) of its benefits for mood disorders remains incompletely understood. Benefits of rTMS have been tied to enhanced neuroplasticity in specific brain pathways. We summarize here the evidence that rTMS entrains and resets thalamocortical oscillators, normalizes regulation and facilitates reemergence of intrinsic cerebral rhythms, and through this mechanism restores normal brain function. This entrainment and resetting may be a critical step in engendering neuroplastic changes and the antidepressant effects of rTMS. It may be possible to modify the method of rTMS administration to enhance this MOA and achieve better antidepressant effectiveness. We propose that rTMS can be administered: (1) synchronized to a patient's individual alpha frequency (IAF), or synchronized rTMS (sTMS); (2) as a low magnetic field strength sinusoidal waveform; and, (3) broadly to multiple brain areas simultaneously. We present here the theory and evidence indicating that these modifications could enhance the therapeutic effectiveness of rTMS for the treatment of MDD.
Leuchter, Andrew F.; Cook, Ian A.; Jin, Yi; Phillips, Bill
Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex
Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects.
Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.
76 FR 44489 - Medical Devices; Neurological Devices; Classification of Repetitive Transcranial Magnetic...
Federal Register 2010, 2011, 2012, 2013
...repetitive pulsed magnetic fields of sufficient magnitude...effects; Magnetic field effects on functioning... Hazards caused by electromagnetic interference and electrostatic...Labeling. Magnetic field effects on functioning...Hazards caused by electromagnetic...
Extended Remediation of Sleep Deprived-Induced Working Memory Deficits Using fMRI-guided Transcranial Magnetic Stimulation
Study Objectives: We attempted to prevent the development of working memory (WM) impairments caused by sleep deprivation using fMRI-guided repetitive transcranial magnetic stimulation (rTMS). Novel aspects of our fMRI-guided rTMS paradigm included the use of sophisticated covariance methods to identify functional networks in imaging data, and the use of fMRI-targeted rTMS concurrent with task performance to modulate plasticity effects over a longer term. Design: Between-groups mixed model. Setting: TMS, MRI, and sleep laboratory study. Participants: 27 subjects (13 receiving Active rTMS, and 14 Sham) completed the sleep deprivation protocol, with another 21 (10 Active, 11 Sham) non-sleep deprived subjects run in a second experiment. Interventions: Our previous covariance analysis had identified a network, including occipital cortex, which demonstrated individual differences in resilience to the deleterious effects of sleep deprivation on WM performance. Five Hz rTMS was applied to left lateral occipital cortex while subjects performed a WM task during 4 sessions over the course of 2 days of total sleep deprivation. Measurements and Results: At the end of the sleep deprivation period, Sham sleep deprived subjects exhibited degraded performance in the WM task. In contrast, those receiving Active rTMS did not show the slowing and lapsing typical in sleep deprivation, and instead performed similarly to non- sleep deprived subjects. Importantly, the Active sleep deprivation group showed rTMS-induced facilitation of WM performance a full 18 hours after the last rTMS session. Conclusions: Over the course of sleep deprivation, these results indicate that rTMS applied concurrently with WM task performance affected neural circuitry involved in WM to prevent its full impact. Citation: Luber B; Steffener J; Tucker A; Habeck C; Peterchev AV; Deng ZD; Basner RC; Stern Y; Lisanby SH. Extended remediation of sleep deprived-induced working memory deficits using fMRI-guided transcranial magnetic stimulation. SLEEP 2013;36(6):857-871.
Luber, Bruce; Steffener, Jason; Tucker, Adrienne; Habeck, Christian; Peterchev, Angel V.; Deng, Zhi-De; Basner, Robert C.; Stern, Yaakov; Lisanby, Sarah H.
Safe use of repetitive transcranial magnetic stimulation in patients with implanted vagus nerve stimulators.
Vagus nerve stimulation (VNS) and repetitive transcranial stimulation (rTMS) devices are FDA cleared for therapeutic use in treatment resistant depression. Since VNS systems have ferromagnetic components and large-scale safety testing has not been done, the implanted VNS device is considered a contraindication for rTMS therapy. This contraindication should not be considered absolute, as VNS components typically lie outside the electromagnetic field generated by an rTMS treatment coil. We solicited information from clinicians at several academic medical centers through an informal survey about their use of rTMS for depressed patients with implanted VNS systems, and reviewed relevant safety issues with one rTMS device manufacturer. rTMS clinical practices may use special consent procedures and take additional precautions to enhance safety in these situations. Specific recommendations are provided for minimizing risks (heating or movement of VNS components and unintended change in VNS stimulation parameters) when delivering rTMS to patients with implanted VNS systems. PMID:24794163
Philip, Noah S; Carpenter, S Louisa; Carpenter, Linda L
Fifteen minutes of left prefrontal repetitive transcranial magnetic stimulation acutely increases thermal pain thresholds in healthy adults
BACKGROUND: Transcranial magnetic stimulation (TMS) of the motor cortex appears to alter pain perception in healthy adults and in patients with chronic neuropathic pain. There is, however, emerging brain imaging evidence that the left prefrontal cortex is involved in pain inhibition in humans. OBJECTIVE: Because the prefrontal cortex may be involved in descending pain inhibitory systems, the present pilot study was conducted to investigate whether stimulation of the left prefrontal cortex via TMS might affect pain perception in healthy adults. METHODS: Twenty healthy adults with no history of depression or chronic pain conditions volunteered to participate in a pilot laboratory study in which thermal pain thresholds were assessed before and after 15 min of repetitive TMS (rTMS) over the left prefrontal cortex (10 Hz, 100% resting motor threshold, 2 s on, 60 s off, 300 pulses total). Subjects were randomly assigned to receive either real or sham rTMS and were blind to condition. RESULTS: Subjects who received real rTMS demonstrated a significant increase in thermal pain thresholds following TMS. Subjects receiving sham TMS experienced no change in pain threshold. CONCLUSIONS: rTMS over the left prefrontal cortex increases thermal pain thresholds in healthy adults. Results from the present study support the idea that the left prefrontal cortex may be a promising TMS cortical target for the management of pain. More research is needed to establish the reliability of these findings, maximize the effect, determine the length of effect and elucidate possible mechanisms of action.
Borckardt, Jeffrey J; Smith, Arthur R; Reeves, Scott T; Weinstein, Mitchell; Kozel, F Andrew; Nahas, Ziad; Shelley, Neal; Branham, R Kyle; Thomas, K Jackson; George, Mark S
Slow waves, synaptic plasticity and information processing: insights from transcranial magnetic stimulation and high-density EEG experiments
Sleep slow waves are the main phenomenon underlying NREM sleep. They are homeostatically regulated, they are thought to be linked to learning and plasticity processes and, at the same time, they are associated with marked changes in cortical information processing. Using transcranial magnetic stimulation (TMS) and high-density (hd) EEG we can measure slow waves, induce/measure plastic changes in the cerebral cortex and we can directly assess cortico-cortical information transmission. In this manuscript we review the results of recent experiments in which TMS/hd-EEG is used to demonstrate (i) a causal link between cortical plastic changes and sleep slow waves and (ii) a causal link between slow waves and the decreased ability of thalamocortical circuits to integrate information and to generate conscious experience during NREM sleep. The data presented here suggest a unifying mechanism linking slow waves, plasticity and cortical information integration; moreover, they suggest that TMS can be used as a non-pharmacological mean to controllably induce slow waves in the human cerebral cortex.
Marcello, Massimini; Giulio, Tononi; Reto, Huber
Transcranial magnetic stimulation as an investigative tool for motor dysfunction and recovery in stroke: an overview for neurorehabilitation clinicians
Rationale An improved understanding of motor dysfunction and recovery after stroke has important clinical implications that may lead to the design of more effective rehabilitation strategies for patients with hemiparesis. Scope Transcranial magnetic stimulation (TMS) is a safe and painless tool that has been used in conjunction with other existing diagnostic tools to investigate motor pathophysiology in stroke patients. Since TMS emerged over two decades ago, its application in clinical and basic neuroscience has expanded worldwide. TMS can quantify the corticomotor excitability properties of clinically affected and unaffected muscles, and probe local cortical networks, as well as remote but functionally related areas. This provides novel insight into the physiology of neural circuits underlying motor dysfunction, and brain reorganization during the motor recovery process. This important tool needs to be used with caution by clinical investigators, its limitations need to be understood and the results should be interpreted along with clinical evaluation in this patient population. Summary In this review, we provide an overview of the rationale, implementation and limitations of TMS to study stroke motor physiology. This knowledge may be useful to guide future rehabilitation treatments by assessing and promoting functional plasticity.
Cortes, Mar; Black-Schaffer, Randie M; Edwards, Dylan J
Bilateral repetitive transcranial magnetic stimulation combined with intensive swallowing rehabilitation for chronic stroke Dysphagia: a case series study.
The purpose of this study was to clarify the safety and feasibility of a 6-day protocol of bilateral repetitive transcranial magnetic stimulation (rTMS) combined with intensive swallowing rehabilitation for chronic poststroke dysphagia. In-hospital treatment was provided to 4 poststroke patients (age at treatment: 56-80 years; interval between onset of stroke and treatment: 24-37 months) with dysphagia. Over 6 consecutive days, each patient received 10 sessions of rTMS at 3 Hz applied to the pharyngeal motor cortex bilaterally, followed by 20 min of intensive swallowing rehabilitation exercise. The swallowing function was evaluated by the Penetration Aspiration Scale (PAS), Modified Mann Assessment of Swallowing Ability (MMASA), Functional Oral Intake Scale (FOIS), laryngeal elevation delay time (LEDT) and Repetitive Saliva-Swallowing Test (RSST) on admission and at discharge. All patients completed the 6-day treatment protocol and none showed any adverse reactions throughout the treatment. The combination treatment improved laryngeal elevation delay time in all patients. Our proposed protocol of rTMS plus swallowing rehabilitation exercise seems to be safe and feasible for chronic stroke dysphagia, although its efficacy needs to be confirmed in a large number of patients. PMID:24803904
Momosaki, Ryo; Abo, Masahiro; Kakuda, Wataru
Benefit of Multiple Sessions of Perilesional Repetitive Transcranial Magnetic Stimulation for an Effective Rehabilitation of Visuo-Spatial Function
Non-invasive neurostimulation techniques have been used alone or in conjunction with rehabilitation therapy to treat the neurological sequelae of brain damage with rather variable therapeutic outcomes. One potential factor limiting a consistent success for such techniques may be the few sessions carried out in patients, despite reports that their accrual may play a key role in alleviating neurological deficits long-term. In this study, we tested the effects of seventy consecutive sessions of perilesional high frequency (10 Hz) repetitive transcranial magnetic stimulation (rTMS) in the treatment of chronic neglect deficits in a well-established feline model of visuo-spatial neglect. Under identical rTMS parameters and visuo-spatial testing regimes, half of the subjects improved in visuo-spatial orienting performance. The other half experienced either none or extremely moderate ameliorations in the neglected hemispace and displayed transient patterns of maladaptive visuo-spatial behavior. Detailed analyses suggest that lesion location and extent did not account for the behavioral differences observed between these two groups of animals. We conclude that multi-session perilesional rTMS regimes have the potential to induce functional ameliorations following focal chronic brain injury, and that behavioral performance prior to the onset of the rTMS treatment is the factor that best predicts positive outcomes for non-invasive neurostimulation treatments in visuo-spatial neglect.
Afifi, Linda; Rushmore, R. Jarrett; Valero-Cabre, Antoni
Repetitive transcranial magnetic stimulation over the temporoparietal junction influences distinction of self from famous but not unfamiliar others.
Neuroimaging and studies using repetitive transcranial magnetic stimulation (rTMS) have shown that a hierarchically organized neural network comprising the right temporoparietal junction (TPJ) and the prefrontal cortex is involved when discriminating one's own face from other faces. Less clear, however, is the role of attention in self-other distinction. Accordingly, the present study aimed at investigating the role of the right TPJ in self-other and other-other discrimination by using low-frequency repetitive TMS while controlling for attention. We tested 10 healthy right-handed subjects using a video task, which comprised morphings of famous, unfamiliar, and the subjects' own faces that gradually transformed into each other. Reaction time (RT) was measured by pushing a mouse button once a change of identity was recognized. Subjects received rTMS over the right TPJ, sham stimulation, or no stimulation, separated by 1 week. rTMS over the right TPJ influenced the distinction between one's own and a famous face. Specifically, subjects needed more features to identify the famous face after rTMS to the right TPJ compared with the control conditions. No rTMS effect was observed when subjects had to distinguish between their own and unfamiliar faces, nor did rTMS affect attention. This suggests that the right TPJ is involved in self-other distinction, specifically if the other's face is familiar to the subject. PMID:23067386
Heinisch, Christine; Kr�ger, Marie C; Br�ne, Martin
Transcranial magnetic stimulation of visual cortex in memory: cortical state, interference and reactivation of visual content in memory.
Memory for perceptual events includes the neural representation of the sensory information at short or longer time scales. Recent transcranial magnetic stimulation (TMS) studies of human visual cortex provided evidence that sensory cortex contributes to memory functions. In this review, we provide an exhaustive overview of these studies and ascertain how well the available evidence supports the idea of a causal role of sensory cortex in memory retention and retrieval. We discuss the validity and implications of the studies using a number of methodological and theoretical criteria that are relevant for brain stimulation of visual cortex. While most studies applied TMS to visual cortex to interfere with memory functions, a handful of pioneering studies used TMS to 'reactivate' memories in visual cortex. Interestingly, similar effects of TMS on memory were found in different memory tasks, which suggests that different memory systems share a neural mechanism of memory in visual cortex. At the same time, this neural mechanism likely interacts with higher order brain areas. Based on this overview and evaluation, we provide a first attempt to an integrative framework that describes how sensory processes contribute to memory in visual cortex, and how higher order areas contribute to this mechanism. PMID:22921373
van de Ven, Vincent; Sack, Alexander T
Topographic contribution of early visual cortex to short-term memory consolidation: a transcranial magnetic stimulation study.
The neural correlates for retention of visual information in visual short-term memory are considered separate from those of sensory encoding. However, recent findings suggest that sensory areas may play a role also in short-term memory. We investigated the functional relevance, spatial specificity, and temporal characteristics of human early visual cortex in the consolidation of capacity-limited topographic visual memory using transcranial magnetic stimulation (TMS). Topographically specific TMS pulses were delivered over lateralized occipital cortex at 100, 200, or 400 ms into the retention phase of a modified change detection task with low or high memory loads. For the high but not the low memory load, we found decreased memory performance for memory trials in the visual field contralateral, but not ipsilateral to the side of TMS, when pulses were delivered at 200 ms into the retention interval. A behavioral version of the TMS experiment, in which a distractor stimulus (memory mask) replaced the TMS pulses, further corroborated these findings. Our findings suggest that retinotopic visual cortex contributes to the short-term consolidation of topographic visual memory during early stages of the retention of visual information. Further, TMS-induced interference decreased the strength (amplitude) of the memory representation, which most strongly affected the high memory load trials. PMID:22219265
van de Ven, Vincent; Jacobs, Christianne; Sack, Alexander T
Bilateral Repetitive Transcranial Magnetic Stimulation Combined with Intensive Swallowing Rehabilitation for Chronic Stroke Dysphagia: A Case Series Study
The purpose of this study was to clarify the safety and feasibility of a 6-day protocol of bilateral repetitive transcranial magnetic stimulation (rTMS) combined with intensive swallowing rehabilitation for chronic poststroke dysphagia. In-hospital treatment was provided to 4 poststroke patients (age at treatment: 56�80 years; interval between onset of stroke and treatment: 24�37 months) with dysphagia. Over 6 consecutive days, each patient received 10 sessions of rTMS at 3 Hz applied to the pharyngeal motor cortex bilaterally, followed by 20 min of intensive swallowing rehabilitation exercise. The swallowing function was evaluated by the Penetration Aspiration Scale (PAS), Modified Mann Assessment of Swallowing Ability (MMASA), Functional Oral Intake Scale (FOIS), laryngeal elevation delay time (LEDT) and Repetitive Saliva-Swallowing Test (RSST) on admission and at discharge. All patients completed the 6-day treatment protocol and none showed any adverse reactions throughout the treatment. The combination treatment improved laryngeal elevation delay time in all patients. Our proposed protocol of rTMS plus swallowing rehabilitation exercise seems to be safe and feasible for chronic stroke dysphagia, although its efficacy needs to be confirmed in a large number of patients.
Assessing brain plasticity across the lifespan with transcranial magnetic stimulation: why, how, and what is the ultimate goal?
Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the twenty-first century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally "normal" brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual's life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual's brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS), which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index (BHI) to enable objective correlates of an individual's brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions. PMID:23565072
Freitas, Catarina; Farzan, Faranak; Pascual-Leone, Alvaro
Motor demand-dependent improvement in accuracy following low-frequency transcranial magnetic stimulation of left motor cortex
The role of primary motor cortex (M1) in the control of voluntary movements is still unclear. In brain functional imaging studies of unilateral hand performance, bilateral M1 activation is inconsistently observed, and disruptions of M1 using repetitive transcranial magnetic stimulation (rTMS) lead to variable results in the hand motor performance. As the motor tasks differed qualitatively in these studies, it is conceivable that M1 contribution differs depending on the level of skillfulness. The objective of the present study was to determine whether M1 contribution to hand motor performance differed depending on the level of precision of the motor task. Here, we used low-frequency rTMS of left M1 to determine its effect on the performance of a pointing task that allows the parametric increase of the level of precision and thereby increase the level of required precision quantitatively. We found that low-frequency rTMS improved performance in both hands for the task with the highest demand on precision, whereas performance remained unchanged for the tasks with lower demands. These results suggest that the functional relevance of M1 activity for motor performance changes as a function of motor demand. The bilateral effect of rTMS to left M1 would also support the notion of M1 functions at a higher level in motor control by integrating afferent input from nonprimary motor areas.
Hines, Benjamin; Shuster, Linda; Pergami, Paola; Mathes, Adam
Reliability of transcranial magnetic stimulation induced corticomotor excitability measurements for a hand muscle in healthy and chronic stroke subjects.
Transcranial magnetic stimulation (TMS) has been used to evaluate neuroplastic changes in the brain in clinical trials. The purpose of this study was to establish the test-retest reliability of 4 TMS measures of corticomotor excitability - (1) resting motor threshold, (2) slope of input-output curve, (3) peak motor evoked potential amplitude, and (4) cortical silent period duration for the corticospinal projections to the first dorsal interosseous of the contralateral hand. Fourteen healthy subjects (mean age 27.4years) and 27 subjects with stroke-induced upper limb hemiparesis (mean age 61.3years) completed 2 repeated sessions of assessment of 1week apart. Good to excellent test-retest reliability of the TMS measurements was confirmed in the stroke subjects for both hemispheres with the ICC?0.88. Measurement reliability was good (ICC?0.75) for the 4 outcome measures in healthy subjects. Contrary to the similarity in standard error of measurements in both hemispheres for outcome measures (1) to (3) in the stroke subjects, that of the cortical silent period duration was larger in magnitude in the lesioned hemisphere. The test-retest reliability coefficients determined for the four corticomotor excitability measurements allowed the estimation of 95% minimal detectable changes of these outcome variables for the respective subject group in future clinical trials. PMID:24792099
Liu, Hao; Au-Yeung, Stephanie S Y
Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the twenty-first century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally �normal� brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual's life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual's brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS), which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index (BHI) to enable objective correlates of an individual's brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions.
Transcranial magnetic stimulation to the frontal operculum and supramarginal gyrus disrupts planning of outcome-based hand-object interactions.
Behavioral data suggest that goals inform the selection of motor commands during planning. We investigated the neural correlates that mediate planning of goal-oriented actions by asking 10 healthy subjects to prepare either a goal-specific movement toward a common object (a cup), with the intent of grasping-to-pour (liquid into it) or grasping-to-move (to another location) the object, or performing a non-object-oriented stimulus-response task (move a finger). Single-pulse transcranial magnetic stimulation was administered on 50% of trials to the supramarginal gyrus (SMG), anterior intraparietal sulcus, inferior frontal gyrus opercularis (IFGo), and triangularis during motor planning. Stimulation to SMG and IFGo caused a significant delay in planning goal-oriented actions but not responses to an arbitrary stimulus. Despite the delay, movement execution was not affected, suggesting that the motor plan remained intact. Our data implicate the SMG and IFGo in planning goal-oriented hand-object interactions. PMID:19118175
Tunik, Eugene; Lo, On-Yee; Adamovich, Sergei V
Empathy Moderates the Effect of Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex on Costly Punishment
Humans incur considerable costs to punish unfairness directed towards themselves or others. Recent studies using repetitive transcranial magnetic stimulation (rTMS) suggest that the right dorsolateral prefrontal cortex (DLPFC) is causally involved in such strategic decisions. Presently, two partly divergent hypotheses are discussed, suggesting either that the right DLPFC is necessary to control selfish motives by implementing culturally transmitted social norms, or is involved in suppressing emotion-driven prepotent responses to perceived unfairness. Accordingly, we studied the role of the DLPFC in costly (i.e. third party) punishment by applying rTMS to the left and right DLPFC before playing a Dictator Game with the option to punish observed unfair behavior (DG-P). In addition, sham stimulation took place. Individual differences in empathy were assessed with the German version of the Interpersonal Reactivity Index. Costly punishment increased (non-significantly) upon disruption of the right � but not the left � DLPFC as compared to sham stimulation. However, empathy emerged as a highly significant moderator variable of the effect of rTMS over the right, but not left, DLPFC, suggesting that the right DLPFC is involved in controlling prepotent emotional responses to observed unfairness, depending on individual differences in empathy.
Heinisch, Christine; Tas, Cumhur; Wischniewski, Julia; Gunturkun, Onur
Neural correlates of dual-task practice benefit on motor learning: a repetitive transcranial magnetic stimulation study.
Dual-task practice has been previously shown to enhance motor learning when both primary and secondary tasks engage similar cognitive processes. In the present study, participants practiced a finger sequence task with the non-dominant hand under a single-task condition (i.e. without a probe task) or a dual-task condition in which a probe choice reaction time (CRT) task was presented during the preparation phase (before movement onset) of the finger task. It was hypothesised that by engaging similar 'planning' processes, the dual-task condition may facilitate the activation of shared 'planning' circuitry that includes dorsal premotor cortex (dPM), an important neural substrate for CRT task performance and movement preparation. Repetitive transcranial magnetic stimulation (rTMS; 1 Hz) was applied to the contralateral dPM immediately following practice. Motor learning was assessed by a retention test conducted ~ 24 h after practice. Consistent with our previous results, the dual-task condition enhanced learning compared with the single-task condition. rTMS applied to dPM attenuated the dual-task practice benefit on motor learning. In contrast, rTMS to M1 did not attenuate the dual-task practice benefit, suggesting the rTMS effect was specific to dPM. Our findings suggest a unique role of dPM in mediating the dual-task practice effect on motor learning. PMID:23489946
Goh, Hui-Ting; Lee, Ya-Yun; Fisher, Beth E
Neglect-like visual exploration behaviour after theta burst transcranial magnetic stimulation of the right posterior parietal cortex.
The right posterior parietal cortex (PPC) is critically involved in visual exploration behaviour, and damage to this area may lead to neglect of the left hemispace. We investigated whether neglect-like visual exploration behaviour could be induced in healthy subjects using theta burst repetitive transcranial magnetic stimulation (rTMS). To this end, one continuous train of theta burst rTMS was applied over the right PPC in 12 healthy subjects prior to a visual exploration task where colour photographs of real-life scenes were presented on a computer screen. In a control experiment, stimulation was also applied over the vertex. Eye movements were measured, and the distribution of visual fixations in the left and right halves of the screen was analysed. In comparison to the performance of 28 control subjects without stimulation, theta burst rTMS over the right PPC, but not the vertex, significantly decreased cumulative fixation duration in the left screen-half and significantly increased cumulative fixation duration in the right screen-half for a time period of 30 min. These results suggest that theta burst rTMS is a reliable method of inducing transient neglect-like visual exploration behaviour. PMID:18371083
Nyffeler, Thomas; Cazzoli, Dario; Wurtz, Pascal; L�thi, Mathias; von Wartburg, Roman; Chaves, Silvia; D�ruaz, Anouk; Hess, Christian W; M�ri, Ren� M
The effect of music on corticospinal excitability is related to the perceived emotion: a transcranial magnetic stimulation study.
Transcranial magnetic stimulation (TMS) and neuroimaging studies suggest a functional link between the emotion-related brain areas and the motor system. It is not well understood, however, whether the motor cortex activity is modulated by specific emotions experienced during music listening. In 23 healthy volunteers, we recorded the motor evoked potentials (MEP) following TMS to investigate the corticospinal excitability while subjects listened to music pieces evoking different emotions (happiness, sadness, fear, and displeasure), an emotionally neutral piece, and a control stimulus (musical scale). Quality and intensity of emotions were previously rated in an additional group of 30 healthy subjects. Fear-related music significantly increased the MEP size compared to the neutral piece and the control stimulus. This effect was not seen with music inducing other emotional experiences and was not related to changes in autonomic variables (respiration rate, heart rate). Current data indicate that also in a musical context, the excitability of the corticomotoneuronal system is related to the emotion expressed by the listened piece. PMID:22405960
Giovannelli, Fabio; Banfi, Chiara; Borgheresi, Alessandra; Fiori, Elisa; Innocenti, Iglis; Rossi, Simone; Zaccara, Gaetano; Viggiano, Maria Pia; Cincotta, Massimo
Bilateral vs. unilateral repetitive transcranial magnetic stimulation in treating major depression: a meta-analysis of randomized controlled trials.
Previous studies have demonstrated inconsistent findings regarding the efficacy of bilateral vs. unilateral repetitive transcranial magnetic stimulation (rTMS) in treating major depressive disorder (MDD). Therefore, this meta-analysis was conducted to compare the efficacy of these two rTMS modalities. Data were obtained from seven randomized controlled trials (RCTs) consisting of 509 subjects. Bilateral and unilateral rTMS displayed comparable efficacy in treating MDD with a pooled odds ratios of 1.06 (95% confidence interval (CI)=0.58-1.91) for response rates and 1.05 (95% CI=0.52-2.11) for remission rates. Subgroup analysis found that bilateral rTMS was equally effective in comparison with both left and right unilateral rTMS. No significant differences in drop-out rates were found. No publication bias was detected. In conclusion, the pooled examination demonstrated that bilateral rTMS displays comparable anti-depressant efficacy and acceptability to unilateral rTMS in treating MDD. These findings suggest that simultaneous rTMS of the right and left dorsolateral prefrontal cortices in MDD patients does not provide marginal benefits in terms of efficacy or acceptability. As the number of RCTs included here was limited, further large-scale multi-center RCTs are required to validate our conclusions. PMID:24889845
Chen, Jian-Jun; Liu, Zhao; Zhu, Dan; Li, Qi; Zhang, Hongzhi; Huang, Hua; Wei, Youdong; Mu, Jun; Yang, Deyu; Xie, Peng
Hirayama disease is a pure spinal motor neuron disorder--a combined DTI and transcranial magnetic stimulation study.
Hirayama disease (HirD) is a juvenile spinal muscular atrophy predominantly affecting young men with an initially progressive course followed by a stable plateau within several years. It is a matter of debate whether HirD is a widespread motor neuron or more focal cervical cord disease. Whether the supraspinal pathways of the corticospinal tract (CST) are also affected has not been studied systematically. We analyzed CST integrity in seven HirD patients and 11 controls of similar age and gender using diffusion tensor imaging at a 1.5-T scanner and central motor conduction time (CMCT) using transcranial magnetic stimulation. The apparent diffusion coefficient, fractional anisotropy, and axial and radial diffusivity coefficients were determined bilaterally at four representative CST levels and along the whole CST using a probabilistic fiber tracking approach. There were no differences between the initially affected and the contralateral side in HirD patients and no difference between HirD patients and controls for both the ROI-based and the whole CST analyses. Radial diffusivity of the CST was positively correlated with years of disease progression in HirD patients. CMCT was normal in HirD patients. Combined anatomical and functional measurements established normal integrity of the supraspinal CST in HirD patients lending support to the notion that HirD is a pure spinal motor neuron disorder. PMID:23007195
Boelmans, Kai; Kaufmann, J�rn; Schmelzer, Sophie; Vielhaber, Stefan; Kornhuber, Malte; M�nchau, Alexander; Zierz, Stephan; Gaul, Charly
Transcranial magnetic stimulation in a finger-tapping task separates motor from timing mechanisms and induces frequency doubling.
We study the interplay between motor programs and their timing in the brain by using precise pulses of transcranial magnetic stimulation (TMS) applied to the primary motor cortex. The movement of the finger performing a tapping task is periodically perturbed in synchronization with a metronome. TMS perturbation can profoundly affect both the finger trajectory and its kinematics, but the tapping accuracy itself is surprisingly not affected. The motion of the finger during the TMS perturbation can be categorized into two abnormal behaviors that subjects were unaware of: a doubling of the frequency of the tap and a stalling of the finger for half the period. More stalls occurred as the tapping frequency increased. In addition, an enhancement of the velocity of the finger on its way up was observed. We conclude that the timing process involved in controlling the tapping movement is separate from the motor processes in charge of execution of the motor commands. We speculate that the TMS is causing a release of the motor plan ahead of time into activation mode. The observed doubles and stalls are then the result of an indirect interaction in the brain, making use of an existing motor plan to correct the preactivation and obtain the temporal goal of keeping the beat. PMID:17488200
Levit-Binnun, Nava; Handzy, Nestor Z; Peled, Avi; Modai, Ilan; Moses, Elisha
Comparison of Transcranial Magnetic Stimulation and Electroneuronography Between Bell's Palsy and Ramsay Hunt Syndrome in Their Acute Stages
Objective To examine the neurophysiologic status in patients with idiopathic facial nerve palsy (Bell's palsy) and Ramsay Hunt syndrome (herpes zoster oticus) within 7 days from onset of symptoms, by comparing the amplitude of compound muscle action potentials (CMAP) of facial muscles in electroneuronography (ENoG) and transcranial magnetic stimulation (TMS). Methods The facial nerve conduction study using ENoG and TMS was performed in 42 patients with Bell's palsy and 14 patients with Ramsay Hunt syndrome within 7 days from onset of symptoms. Denervation ratio was calculated as CMAP amplitude evoked by ENoG or TMS on the affected side as percentage of the amplitudes on the healthy side. The severity of the facial palsy was graded according to House-Brackmann facial grading scale (H-B FGS). Results In all subjects, the denervation ratio in TMS (71.53�18.38%) was significantly greater than the denervation ratio in ENoG (41.95�21.59%). The difference of denervation ratio between ENoG and TMS was significantly smaller in patients with Ramsay Hunt syndrome than in patients with Bell's palsy. The denervation ratio of ENoG or TMS did not correlated significantly with the H-B FGS. Conclusion In the electrophysiologic study for evaluation in patients with facial palsy within 7 days from onset of symptoms, ENoG and TMS are useful in gaining additional information about the neurophysiologic status of the facial nerve and may help to evaluate prognosis and set management plan.
Hur, Dong Min; Lee, Young Hee; Kim, Sung Hoon; Park, Jung Mi; Kim, Ji Hyun; Yong, Sang Yeol; Shinn, Jong Mock; Oh, Kyung Joon
Changing cortical excitability with low-frequency transcranial magnetic stimulation can induce sustained disruption of tactile perception.
Transcranial magnetic stimulation (TMS) is promising as a therapeutic tool, and TMS of the motor system has served as a model for regionally specific modulations of cortical excitability. It is unclear, however, to what extent response characteristics of the motor cortex are representative of other brain systems. We wanted to determine whether TMS could induce a sustained disruption of somatosensory processing beyond the stimulation duration, similar to observations in the motor system. We applied 1-Hz TMS at 110% of subjects' motor thresholds for a variable duration over the right and left somatosensory cortex before subjects performed a tactile frequency discrimination task with the left hand. Tactile discrimination was impaired only after TMS over the right somatosensory cortex (analysis of variance: p <.01). The duration of this impairment correlated with the duration of the preceding TMS; the effect lasted approximately 2 min after 5 min of TMS, 4 min after 10 min of TMS, and 8 min after 20 min of TMS. Two conclusions arise: 1) low-frequency TMS can interfere with tactile perception in a robust and sustained way, and 2) TMS dosing parameters effective in the motor system are also effective in the somatosensory system and may reflect a modality-independent response characteristic of the cerebral cortex. PMID:12547474
Knecht, Stefan; Ellger, Tanja; Breitenstein, Caterina; Bernd Ringelstein, Erich; Henningsen, Henning
Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research.
This article is based on a consensus conference, which took place in Certosa di Pontignano, Siena (Italy) on March 7-9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings. Over the past decade the scientific and medical community has had the opportunity to evaluate the safety record of research studies and clinical applications of TMS and repetitive TMS (rTMS). In these years the number of applications of conventional TMS has grown impressively, new paradigms of stimulation have been developed (e.g., patterned repetitive TMS) and technical advances have led to new device designs and to the real-time integration of TMS with electroencephalography (EEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Thousands of healthy subjects and patients with various neurological and psychiatric diseases have undergone TMS allowing a better assessment of relative risks. The occurrence of seizures (i.e., the most serious TMS-related acute adverse effect) has been extremely rare, with most of the few new cases receiving rTMS exceeding previous guidelines, often in patients under treatment with drugs which potentially lower the seizure threshold. The present updated guidelines review issues of risk and safety of conventional TMS protocols, address the undesired effects and risks of emerging TMS interventions, the applications of TMS in patients with implanted electrodes in the central nervous system, and safety aspects of TMS in neuroimaging environments. We cover recommended limits of stimulation parameters and other important precautions, monitoring of subjects, expertise of the rTMS team, and ethical issues. While all the recommendations here are expert based, they utilize published data to the extent possible. PMID:19833552
Rossi, Simone; Hallett, Mark; Rossini, Paolo M; Pascual-Leone, Alvaro
Coil positioning system for repetitive transcranial magnetic stimulation treatment by ToF camera ego-motion.
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method for treating various neurological and psychiatric disorders. With the growing demands of neuropathic pain patients and their increasing numbers, rTMS treatment tools are becoming more necessary. rTMS uses electromagnetic induction to induce weak electric currents by rapidly changing the magnetic field. Targeting the electric current to a specific part of the brain is one treatment for pain relief. This paper focuses on treatment for neuropathic pain caused by a lesion or disease of the central or peripheral nervous system, including stroke, trauma, or surgery. However, the current style of rTMS treatment is still developing and is so technically specialized that only a limited number of hospitals and only a handful of specialists can provide this therapy. The existing rTMS systems use an optical markerbased 3D sensing technique that positions the stimulation coil to target the small region of interest in the brain through coregistration with pre-scanned MRI data. This system requires the patient to be immobilized on a bed. The optical markers for 3D sensing are placed on the patient's head to maintain accurate positioning. We propose a constraints-free, markerless rTMS system, which employs ego-motion, a computation technique to estimate relative 3D motion of a camera to what the camera sees. We use a ToF sensor as a camera, which is capble of capturing shape information from a single viewpoint instantly. The markerless target spot is based on the shape features of the patient's face. This paper shows the process of a prototype system and its potential for achieving an easy-to-handle system framework. PMID:24110505
Yasumuro, Yoshihiro; Ebisuwaki, Ryo; Fuyuki, Masahiko; Matsuzaki, Taiga; Saitoh, Youichi
Responses of thenar muscles to transcranial magnetic stimulation of the motor cortex in patients with incomplete spinal cord injury
OBJECTIVE�To investigate changes in electromyographic (EMG) responses to transcranial magnetic stimulation (TMS) of the motor cortex after incomplete spinal cord injury in humans.?METHODS�A group of 10 patients with incomplete spinal cord injury (motor level C3-C8) was compared with a group of 10 healthy control subjects. Surface EMG recordings were made from the thenar muscles. TMS was applied with a 9 cm circular stimulating coil centred over the vertex. The EMG responses to up to 50 magnetic stimuli were rectified and averaged.?RESULTS�Thresholds for compound motor evoked potentials (cMEPs) and suppression of voluntary contraction (SVC) elicited by TMS were higher (p<0.05) in the patient group. Latency of cMEPs was longer (p<0.05) in the patient group in both relaxed (controls 21.3 (SEM 0.5) ms; patients 27.7 (SEM 1.3) ms) and voluntarily contracted (controls 19.8 (SEM 0.5) ms; patients 27.6 (SEM 1.3) ms) muscles. The latency of SVC was longer (p<0.05) in the patients (51.8 (SEM 1.8) ms) than in the controls (33.4 (SEM 1.9) ms). The latency difference (SVC?cMEP) was longer in the patients (25.3 (SEM 2.4) ms) than in the controls (13.4 (SEM 1.6) ms).?CONCLUSION�The longer latency difference between cMEPs and SVC in the patients may reflect a weak or absent early component of cortical inhibition. Such a change may contribute to the restoration of useful motor function after incomplete spinal cord injury.??
Davey, N.; Smith, H.; Wells, E.; Maskill, D.; Savic, G.; Ellaway, P.; Frankel, H.
Magnetic resonance angiography in children with sickle cell disease and abnormal transcranial Doppler ultrasonography findings enrolled in the STOP study.
The stroke prevention study in sickle cell disease (STOP) demonstrated a 90% reduction in stroke risk with transfusion among patients with time-averaged mean cerebral blood velocity (TAMV) of 200 cm/s or more as measured by transcranial Doppler (TCD). In STOP, 232 brain magnetic resonance angiograms (MRAs) were performed on 100 patients, 47 in the transfusion arm and 53 in the standard care arm. Baseline MRA findings were interpreted as normal in 75 patients and as indicating mild stenosis in 4 patients and severe stenosis in 21 patients. Among 35 patients who underwent magnetic resonance angiography within 30 days of random assignment, the TAMV was significantly higher in 7 patients with severe stenosis compared with 28 patients with normal MRA findings or mild stenosis (276.7 +/- 34 vs 215 +/- 15.6 cm/s; P<.001). In the standard care arm, 4 of 13 patients with abnormal MRA findings had strokes compared with 5 of 40 patients with normal MRA findings (P=.03). In this arm, TAMV became normal (less than 170 cm/s) or conditional (170-199 cm/s) in 26 of 38 patients with normal or mildly abnormal baseline MRA but remained abnormal in 8 of 10 patients with severely abnormal baseline MRA. These results suggest