query: Auditory entrainment is strengthened when people see congruent visual and auditory information.

positive: Auditory Cortex Tracks Both Auditory and Visual Stimulus Dynamics Using Low-Frequency Neuronal Phase Modulation Integrating information across sensory domains to construct a unified representation of multi-sensory signals is a fundamental characteristic of perception in ecological contexts. One provocative hypothesis deriving from neurophysiology suggests that there exists early and direct cross-modal phase modulation. We provide evidence, based on magnetoencephalography (MEG) recordings from participants viewing audiovisual movies, that low-frequency neuronal information lies at the basis of the synergistic coordination of information across auditory and visual streams. In particular, the phase of the 2-7 Hz delta and theta band responses carries robust (in single trials) and usable information (for parsing the temporal structure) about stimulus dynamics in both sensory modalities concurrently. These experiments are the first to show in humans that a particular cortical mechanism, delta-theta phase modulation across early sensory areas, plays an important "active" role in continuously tracking naturalistic audio-visual streams, carrying dynamic multi-sensory information, and reflecting cross-sensory interaction in real time.

positive: Congruent Visual Speech Enhances Cortical Entrainment to Continuous Auditory Speech in Noise-Free Conditions. UNLABELLED Congruent audiovisual speech enhances our ability to comprehend a speaker, even in noise-free conditions. When incongruent auditory and visual information is presented concurrently, it can hinder a listener's perception and even cause him or her to perceive information that was not presented in either modality. Efforts to investigate the neural basis of these effects have often focused on the special case of discrete audiovisual syllables that are spatially and temporally congruent, with less work done on the case of natural, continuous speech. Recent electrophysiological studies have demonstrated that cortical response measures to continuous auditory speech can be easily obtained using multivariate analysis methods. Here, we apply such methods to the case of audiovisual speech and, importantly, present a novel framework for indexing multisensory integration in the context of continuous speech. Specifically, we examine how the temporal and contextual congruency of ongoing audiovisual speech affects the cortical encoding of the speech envelope in humans using electroencephalography. We demonstrate that the cortical representation of the speech envelope is enhanced by the presentation of congruent audiovisual speech in noise-free conditions. Furthermore, we show that this is likely attributable to the contribution of neural generators that are not particularly active during unimodal stimulation and that it is most prominent at the temporal scale corresponding to syllabic rate (2-6 Hz). Finally, our data suggest that neural entrainment to the speech envelope is inhibited when the auditory and visual streams are incongruent both temporally and contextually. SIGNIFICANCE STATEMENT Seeing a speaker's face as he or she talks can greatly help in understanding what the speaker is saying. This is because the speaker's facial movements relay information about what the speaker is saying, but also, importantly, when the speaker is saying it. Studying how the brain uses this timing relationship to combine information from continuous auditory and visual speech has traditionally been methodologically difficult. Here we introduce a new approach for doing this using relatively inexpensive and noninvasive scalp recordings. Specifically, we show that the brain's representation of auditory speech is enhanced when the accompanying visual speech signal shares the same timing. Furthermore, we show that this enhancement is most pronounced at a time scale that corresponds to mean syllable length.

negative: Lip movements entrain the observers’ low-frequency brain oscillations to facilitate speech intelligibility During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing.

negative: Acoustic landmarks drive delta-theta oscillations to enable speech comprehension by facilitating perceptual parsing. A growing body of research suggests that intrinsic neuronal slow (<10 Hz) oscillations in auditory cortex appear to track incoming speech and other spectro-temporally complex auditory signals. Within this framework, several recent studies have identified critical-band temporal envelopes as the specific acoustic feature being reflected by the phase of these oscillations. However, how this alignment between speech acoustics and neural oscillations might underpin intelligibility is unclear. Here we test the hypothesis that the 'sharpness' of temporal fluctuations in the critical band envelope acts as a temporal cue to speech syllabic rate, driving delta-theta rhythms to track the stimulus and facilitate intelligibility. We interpret our findings as evidence that sharp events in the stimulus cause cortical rhythms to re-align and parse the stimulus into syllable-sized chunks for further decoding. Using magnetoencephalographic recordings, we show that by removing temporal fluctuations that occur at the syllabic rate, envelope-tracking activity is reduced. By artificially reinstating these temporal fluctuations, envelope-tracking activity is regained. These changes in tracking correlate with intelligibility of the stimulus. Together, the results suggest that the sharpness of fluctuations in the stimulus, as reflected in the cochlear output, drive oscillatory activity to track and entrain to the stimulus, at its syllabic rate. This process likely facilitates parsing of the stimulus into meaningful chunks appropriate for subsequent decoding, enhancing perception and intelligibility.

negative: A 40-Hz auditory potential recorded from the human scalp. Computer techniques readily extract from the brainwaves an orderly sequence of brain potentials locked in time to sound stimuli. The potentials that appear 8 to 80 msec after the stimulus resemble 3 or 4 cycles of a 40-Hz sine wave; we show here that these waves combined to form a single, stable, composite wave when the sounds are repeated at rates around 40 per sec. This phenomenon, the 40-Hz event-related potential (ERP), displays several properties of theoretical and practical interest. First, it reportedly disappears with surgical anesthesia, and it resembles similar phenomena in the visual and olfactory system, facts which suggest that adequate processing of sensory information may require cyclical brain events in the 30- to 50-Hz range. Second, latency and amplitude measurements on the 40-Hz ERP indicate it may contain useful information on the number and basilar membrane location of the auditory nerve fibers a given tone excites. Third, the response is present at sound intensities very close to normal adult thresholds for the audiometric frequencies, a fact that could have application in clinical hearing testing.

negative: Location Coding by Opponent Neural Populations in the Auditory Cortex Although the auditory cortex plays a necessary role in sound localization, physiological investigations in the cortex reveal inhomogeneous sampling of auditory space that is difficult to reconcile with localization behavior under the assumption of local spatial coding. Most neurons respond maximally to sounds located far to the left or right side, with few neurons tuned to the frontal midline. Paradoxically, psychophysical studies show optimal spatial acuity across the frontal midline. In this paper, we revisit the problem of inhomogeneous spatial sampling in three fields of cat auditory cortex. In each field, we confirm that neural responses tend to be greatest for lateral positions, but show the greatest modulation for near-midline source locations. Moreover, identification of source locations based on cortical responses shows sharp discrimination of left from right but relatively inaccurate discrimination of locations within each half of space. Motivated by these findings, we explore an opponent-process theory in which sound-source locations are represented by differences in the activity of two broadly tuned channels formed by contra- and ipsilaterally preferring neurons. Finally, we demonstrate a simple model, based on spike-count differences across cortical populations, that provides bias-free, level-invariant localization—and thus also a solution to the “binding problem” of associating spatial information with other nonspatial attributes of sounds.

negative: A Functional Neuroimaging Study of Sound Localization: Visual Cortex Activity Predicts Performance in Early-Blind Individuals Blind individuals often demonstrate enhanced nonvisual perceptual abilities. However, the neural substrate that underlies this improved performance remains to be fully understood. An earlier behavioral study demonstrated that some early-blind people localize sounds more accurately than sighted controls using monaural cues. In order to investigate the neural basis of these behavioral differences in humans, we carried out functional imaging studies using positron emission tomography and a speaker array that permitted pseudo-free-field presentations within the scanner. During binaural sound localization, a sighted control group showed decreased cerebral blood flow in the occipital lobe, which was not seen in early-blind individuals. During monaural sound localization (one ear plugged), the subgroup of early-blind subjects who were behaviorally superior at sound localization displayed two activation foci in the occipital cortex. This effect was not seen in blind persons who did not have superior monaural sound localization abilities, nor in sighted individuals. The degree of activation of one of these foci was strongly correlated with sound localization accuracy across the entire group of blind subjects. The results show that those blind persons who perform better than sighted persons recruit occipital areas to carry out auditory localization under monaural conditions. We therefore conclude that computations carried out in the occipital cortex specifically underlie the enhanced capacity to use monaural cues. Our findings shed light not only on intermodal compensatory mechanisms, but also on individual differences in these mechanisms and on inhibitory patterns that differ between sighted individuals and those deprived of vision early in life.

negative: How many images are in an auditory scene? If an auditory scene consists of many spatially separated sound sources, how many sound sources can be processed by the auditory system? Experiment I determined how many speech sources could be localized simultaneously on the azimuth plane. Different words were played from multiple loudspeakers, and listeners reported the total number of sound sources and their individual locations. In experiment II the accuracy of localizing one speech source in a mixture of multiple speech sources was determined. An extra sound source was added to an existing set of sound sources, and the task was to localize that extra source. In experiment III the setup and task were the same as in experiment I, except that the sounds were tones. The results showed that the maximum number of sound sources that listeners could perceive was limited to approximately four spatially separated speech signals and three for tonal signals. The localization errors increased along with the increase of total number of sound sources. When four or more speech sources already existed, the accuracy in localizing an additional source was near chance.

negative: Perceptual limits in a simulated "Cocktail party". Numerosity judgments of simultaneous talkers were examined. Listeners were required to report the number of talkers heard when this number varied (1 to 13). Spatial location of talkers (1 or 6 locations), duration of talker voices (0.8 s, 5.0 s, and 15.0 s), and gender arrangement of talkers also were manipulated in four experiments. In all experiments, the proportion of correct numerosity judgments monotonically decreased as talker numbers increased. Perceptual limits, defined as talker numbers with proportion correct scores of 0.5, varied between 3 to 5 talkers, on average, depending on listening conditions, and were significantly higher for spatially separated talkers, for the longer voices, and for the mixed gender voices (Experiments 1, 2, and 3). In addition, Experiment 4 found that average numerosity response times increased monotonically over a range of one to four talkers. These results support the idea that, before counting talkers, listeners perceptually segregate talkers to render numerosity judgments. They also suggest that our functional auditory world for simultaneous voices may consist of, at most, three to five talkers depending on listening situations. In light of these results, possible causes for such perceptual limits are discussed.

negative: Directional perception of distributed sound sources. The perception of spatially distributed sound sources was investigated by conducting two listening experiments in anechoic conditions with 13 loudspeakers evenly distributed in the frontal horizontal plane emitting incoherent noise signals. In the first experiment, widely distributed sound sources with gaps in their distribution emitted pink noise. The results indicated that the exact loudspeaker distribution could not be perceived accurately and that the width of the distribution was perceived to be narrower than it was in reality. Up to three spatially distributed loudspeakers that were simultaneously emitting sound could be individually perceived. In addition, the number of loudspeakers that were indicated as emitting sound was smaller than the actual number. In the second experiment, a reference with 13 loudspeakers and test cases with fewer loudspeakers were presented and their perceived spatial difference was rated. The effect of the noise bandwidth was of particular interest. Noise with different bandwidths centered around 500 and 4000 Hz was used. The results indicated that when the number of loudspeakers was increased from four to seven, the perceived auditory event was very similar to that perceived with 13 loudspeakers at all bandwidths. The perceived differences were larger in wideband noise than in narrow-band noise.

negative: A temporal shift in the circuits mediating retrieval of fear memory Fear memories allow animals to avoid danger, thereby increasing their chances of survival. Fear memories can be retrieved long after learning, but little is known about how retrieval circuits change with time. Here we show that the dorsal midline thalamus of rats is required for the retrieval of auditory conditioned fear at late (24 hours, 7 days, 28 days), but not early (0.5 hours, 6 hours) time points after learning. Consistent with this, the paraventricular nucleus of the thalamus (PVT), a subregion of the dorsal midline thalamus, showed increased c-Fos expression only at late time points, indicating that the PVT is gradually recruited for fear retrieval. Accordingly, the conditioned tone responses of PVT neurons increased with time after training. The prelimbic (PL) prefrontal cortex, which is necessary for fear retrieval, sends dense projections to the PVT. Retrieval at late time points activated PL neurons projecting to the PVT, and optogenetic silencing of these projections impaired retrieval at late, but not early, time points. In contrast, silencing of PL inputs to the basolateral amygdala impaired retrieval at early, but not late, time points, indicating a time-dependent shift in retrieval circuits. Retrieval at late time points also activated PVT neurons projecting to the central nucleus of the amygdala, and silencing these projections at late, but not early, time points induced a persistent attenuation of fear. Thus, the PVT may act as a crucial thalamic node recruited into cortico-amygdalar networks for retrieval and maintenance of long-term fear memories.

negative: Activation of Frontal Neocortical Areas by Vocal Production in Marmosets Primates often rely on vocal communication to mediate social interactions. Although much is known about the acoustic structure of primate vocalizations and the social context in which they are usually uttered, our knowledge about the neocortical control of audio-vocal interactions in primates is still incipient, being mostly derived from lesion studies in squirrel monkeys and macaques. To map the neocortical areas related to vocal control in a New World primate species, the common marmoset, we employed a method previously used with success in other vertebrate species: Analysis of the expression of the immediate early gene Egr-1 in freely behaving animals. The neocortical distribution of Egr-1 immunoreactive cells in three marmosets that were exposed to the playback of conspecific vocalizations and vocalized spontaneously (H/V group) was compared to data from three other marmosets that also heard the playback but did not vocalize (H/n group). The anterior cingulate cortex, the dorsomedial prefrontal cortex and the ventrolateral prefrontal cortex presented a higher number of Egr-1 immunoreactive cells in the H/V group than in H/n animals. Our results provide direct evidence that the ventrolateral prefrontal cortex, the region that comprises Broca's area in humans and has been associated with auditory processing of species-specific vocalizations and orofacial control in macaques, is engaged during vocal output in marmosets. Altogether, our results support the notion that the network of neocortical areas related to vocal communication in marmosets is quite similar to that of Old world primates. The vocal production role played by these areas and their importance for the evolution of speech in primates are discussed.

negative: Light acts directly on organs and cells in culture to set the vertebrate circadian clock. The expression of clock genes in vertebrates is widespread and not restricted to classical clock structures. The expression of the Clock gene in zebrafish shows a strong circadian oscillation in many tissues in vivo and in culture, showing that endogenous oscillators exist in peripheral organs. A defining feature of circadian clocks is that they can be set or entrained to local time, usually by the environmental light-dark cycle. An important question is whether peripheral oscillators are entrained to local time by signals from central pacemakers such as the eyes or are themselves directly light-responsive. Here we show that the peripheral organ clocks of zebrafish are set by light-dark cycles in culture. We also show that a zebrafish-derived cell line contains a circadian oscillator, which is also directly light entrained.

negative: A naturally occurring mouse model of X-linked congenital stationary night blindness. PURPOSE To describe a naturally occurring X-linked recessive mutation, no b-wave (nob), that compromises visual transmission between photoreceptors and second-order neurons in mice. METHODS Affected mice were identified by recording the light-evoked response of the retina, the electroretinogram (ERG). To evaluate visual transmission, cortical potentials were recorded with a scalp electrode. The inheritance pattern for nob was defined by breeding nob animals with normal mice. Retinal histologic analysis was performed by light microscopy. RESULTS Although the photoreceptor-mediated ERG component (a-wave) was normal in nob mice, the major response component reflecting postreceptoral neuronal activity (b-wave) was missing. Visually-driven cortical activity was also abnormal in nob animals. At the light microscopic level, the nob retina appeared to have a normal cytoarchitecture. CONCLUSIONS These findings suggest that the nob defect interferes with the transmission of visual information through the retina and that these mice are a useful model for the study of outer retinal synaptic function. In addition, this mutant mouse seems to provide an animal model for the complete form of congenital stationary night blindness, a human disorder in which patients have a profound loss of rod-mediated visual sensitivity.

negative: Effectiveness of screening older people for impaired vision in community setting: systematic review of evidence from randomised controlled trials. OBJECTIVE To assess whether population screening for impaired vision among older people in the community leads to improvements in vision. DESIGN Systematic review of randomised controlled trials of population screening in the community that included any assessment of vision or visual function with at least 6 months' follow up. SUBJECTS Adults aged 65 or over. MAIN OUTCOME MEASURE Proportions with visual impairment in intervention and control groups with any method of assessing visual impairment. RESULTS There were no trials that primarily assessed visual screening. Outcome data on vision were available for 3494 people in five trials of multiphasic assessment. All the trials used self reported measures for vision impairment, both as screening tools and as outcome measures. The inclusion of a visual screening component in the assessment did not result in improvements in self reported visual problems (pooled odds ratio 1.04:95% confidence interval 0.89 to 1.22). A small reduction (11%) in the number of older people with self reported visual problems cannot be excluded. CONCLUSIONS Screening of asymptomatic older people in the community is not justified on present evidence. Visual impairment in this age group can usually be reduced with treatment. It is unclear why no benefit was seen. Further work is needed to clarify what interventions are appropriate for older people with unreported impairment of vision.

negative: Spatial release from masking based on binaural processing for up to six maskers. Spatial Release from Masking (SRM) was measured for identification of a female target word spoken in the presence of male masker words. Target words from a single loudspeaker located at midline were presented when two, four, or six masker words were presented either from the same source as the target or from spatially separated masker sources. All masker words were presented from loudspeakers located symmetrically around the centered target source in the front azimuth hemifield. Three masking conditions were employed: speech-in-speech masking (involving both informational and energetic masking), speech-in-noise masking (involving energetic masking), and filtered speech-in-filtered speech masking (involving informational masking). Psychophysical results were summarized as three-point psychometric functions relating proportion of correct word identification to target-to-masker ratio (in decibels) for both the co-located and spatially separated target and masker sources cases. SRM was then calculated by comparing the slopes and intercepts of these functions. SRM decreased as the number of symmetrically placed masker sources increased from two to six. This decrease was independent of the type of masking, with almost no SRM measured for six masker sources. These results suggest that when SRM is dependent primarily on binaural processing, SRM is effectively limited to fewer than six sound sources.

negative: The Impact of Location of Progressive Visual Field Loss on Longitudinal Changes in Quality of Life of Patients with Glaucoma. PURPOSE To evaluate the association between rates of progressive loss in different regions of the visual field and longitudinal changes in quality of life (QoL). DESIGN Prospective, observational cohort study. PARTICIPANTS The study included 236 patients with glaucomatous visual field loss followed for an average of 4.3±1.5 years. METHODS All subjects had the 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) performed annually and standard automated perimetry (SAP) at 6-month intervals. Subjects were included if they had a minimum of 2 NEI VFQ-25 and 5 SAP tests during follow-up. Evaluation of rates of visual field change was performed using 4 different regions (central inferior, central superior, peripheral inferior, and peripheral superior) of the integrated binocular visual field. The association between change in NEI VFQ-25 Rasch-calibrated scores and change in different regions of the visual field was investigated with a joint multivariable longitudinal linear mixed model. MAIN OUTCOME MEASURES The relationship between change in QoL scores and change of mean sensitivity in different regions of the visual field. RESULTS There was a significant correlation between change in the NEI VFQ-25 Rasch scores during follow-up and change in different regions of the visual field. Each 1 decibel (dB)/year change in binocular mean sensitivity of the central inferior area was associated with a decline of 2.6 units/year in the NEI VFQ-25 scores (R(2) = 35%; P < 0.001). Corresponding associations with change in QoL scores for the peripheral inferior, central superior, and peripheral superior areas of the visual field had R(2) values of 30%, 24%, and 19%, respectively. The association for the central inferior visual field area was statistically significantly stronger than those of the central superior area (P = 0.011) and peripheral superior area (P = 0.001), but not the peripheral inferior area (P = 0.171). Greater declines in NEI VFQ-25 scores were also seen in patients who had worse visual field sensitivity at baseline. CONCLUSIONS Progressive decline in sensitivity in the central inferior area of the visual field had the strongest association with longitudinal decline in QoL of patients with glaucoma.

negative: Self-Report and Tests of Memory Aging Memory complaints have not correlated well with tests of memory. However, given self-report questions, which tap processes of everyday remembering. sixty volunteers aged 21-84 years adequately rated their memory competence. Categorized into four memory processes, self-report and six tests of verbal, faces, story and nonverbal auditory, visual, and tactual memory ,were canonically correlated (r = 0.67) and both sets of measures declined with age in parallel. Thc old were more accurate than the young in their ratings but by no means on all tests and expectation to perform poorly seemed to have influenced some performances.

negative: The Natural Statistics of Audiovisual Speech Humans, like other animals, are exposed to a continuous stream of signals, which are dynamic, multimodal, extended, and time varying in nature. This complex input space must be transduced and sampled by our sensory systems and transmitted to the brain where it can guide the selection of appropriate actions. To simplify this process, it's been suggested that the brain exploits statistical regularities in the stimulus space. Tests of this idea have largely been confined to unimodal signals and natural scenes. One important class of multisensory signals for which a quantitative input space characterization is unavailable is human speech. We do not understand what signals our brain has to actively piece together from an audiovisual speech stream to arrive at a percept versus what is already embedded in the signal structure of the stream itself. In essence, we do not have a clear understanding of the natural statistics of audiovisual speech. In the present study, we identified the following major statistical features of audiovisual speech. First, we observed robust correlations and close temporal correspondence between the area of the mouth opening and the acoustic envelope. Second, we found the strongest correlation between the area of the mouth opening and vocal tract resonances. Third, we observed that both area of the mouth opening and the voice envelope are temporally modulated in the 2-7 Hz frequency range. Finally, we show that the timing of mouth movements relative to the onset of the voice is consistently between 100 and 300 ms. We interpret these data in the context of recent neural theories of speech which suggest that speech communication is a reciprocally coupled, multisensory event, whereby the outputs of the signaler are matched to the neural processes of the receiver.

negative: Experimental and Theoretical Approaches to Conscious Processing Recent experimental studies and theoretical models have begun to address the challenge of establishing a causal link between subjective conscious experience and measurable neuronal activity. The present review focuses on the well-delimited issue of how an external or internal piece of information goes beyond nonconscious processing and gains access to conscious processing, a transition characterized by the existence of a reportable subjective experience. Converging neuroimaging and neurophysiological data, acquired during minimal experimental contrasts between conscious and nonconscious processing, point to objective neural measures of conscious access: late amplification of relevant sensory activity, long-distance cortico-cortical synchronization at beta and gamma frequencies, and "ignition" of a large-scale prefronto-parietal network. We compare these findings to current theoretical models of conscious processing, including the Global Neuronal Workspace (GNW) model according to which conscious access occurs when incoming information is made globally available to multiple brain systems through a network of neurons with long-range axons densely distributed in prefrontal, parieto-temporal, and cingulate cortices. The clinical implications of these results for general anesthesia, coma, vegetative state, and schizophrenia are discussed.

negative: The flip side of perception-action coupling: locomotor experience and the ontogeny of visual-postural coupling. The possible role of motor development on psychological function is once again a topic of great theoretical and practical importance. The revival of this issue has stemmed from a different approach to the topic, away from Gesell's interest in the long-term prediction of psychological functions from early motoric assessments, toward an attempt to understand how the acquisition of motor skills orchestrates psychological changes. This paper describes how the acquisition of one motor skill, prone locomotion, has been linked to developmental changes in an infant's ability to regulate posture based on information available in patterns of optic flow. It is argued that the onset of prone locomotion presses the infant to differentiate spatially delimited regions of optic flow to effectively and efficiently control the important subtasks nested within the larger task of locomotion, namely, steering, attending to the surface of support, and maintaining postural control. Following this argument, a research program is described that aims to determine if locomotor experience is causally linked to improvements in the ability to functionalize peripheral optic flow for postural control or whether locomotor experience is merely a maturational forecaster of such improvements. Finally, a hypothesis is put forward that links the emergence of wariness of heights to infants' ability to regulate posture on the basis of peripheral optic flow. The paper's overarching theoretical point is the principle of probabilistic epigenesis, which states that one developmental acquisition produces experiences that bring about a host of new developmental changes in the same and different domains.

negative: Motion magnification We present motion magnification, a technique that acts like a microscope for visual motion. It can amplify subtle motions in a video sequence, allowing for visualization of deformations that would otherwise be invisible. To achieve motion magnification, we need to accurately measure visual motions, and group the pixels to be modified. After an initial image registration step, we measure motion by a robust analysis of feature point trajectories, and segment pixels based on similarity of position, color, and motion. A novel measure of motion similarity groups even very small motions according to correlation over time, which often relates to physical cause. An outlier mask marks observations not explained by our layered motion model, and those pixels are simply reproduced on the output from the original registered observations. The motion of any selected layer may be magnified by a user-specified amount; texture synthesis fills-in unseen "holes" revealed by the amplified motions. The resulting motion-magnified images can reveal or emphasize small motions in the original sequence, as we demonstrate with deformations in load-bearing structures, subtle motions or balancing corrections of people, and "rigid" structures bending under hand pressure.

negative: Specific deficit of the ON response in visual transmission by targeted disruption of the mGIuR6 gene Taking advantage of the restricted expression of metabotropic glutamate receptor subtype 6 (mGluR6) in retinal ON bipolar cells, we generated knockout mice lacking mGluR6 expression. The homozygous mutant mice showed a loss of ON responses but unchanged OFF responses to light. The mutant mice displayed no obvious changes in retinal cell organization nor in the projection of optic fibers to the brain. Furthermore, the mGluR6-deficient mice showed visual behavioral responses to light stimulation as examined by shuttle box avoidance behavior experiments using light exposure as a conditioned stimulus. The results demonstrate that mGluR6 is essential in synaptic transmission to the ON bipolar cell and that the OFF response provides an important means for transmitting visual information.

negative: Older People at the End of Life: Delivery of Care and Needs for Improvement from the Perspective of Bereaved Relatives BACKGROUND Due to demographic changes with an increasing number of older people with chronic illness and multimorbidity palliative care for geriatric patients has become increasingly important. The aim of this study was to explore the perspective of bereaved relatives with regard to their experiences and expectations concerning the delivery of care for older people in the last phase of life. METHODS Qualitative interviews with 12 relatives of deceased older patients (aged 60 years or older). The interviews were recorded, transcribed, coded and analysed using the approach of qualitative content analysis according to Mayring. RESULTS The bereaved relatives perceived that the care for geriatric patients in the last phase of life was inappropriate in various respects. They criticised overtreatment (e.g. skin cancer diagnostic) as well as unmet needs (e.g. treatment of pain, patient centred care, communication). Family doctors were seen as the primary contact persons in the professional health system. CONCLUSIONS From the perspective of bereaved relatives care for older people in the last phase of life has serious deficits. They criticise an inappropriate priority setting and the disregard of palliative care. There is a need for better communication and information exchange regarding the needs and expectations of patients and relatives, and regarding the targets of treatment. Therefore it may be helpful to use advance directives more intensively. Furthermore, it seems to be necessary to strengthen generalist palliative care particularly delivered by family doctors and community nurses.

negative: Cineradiography of Monkey Lip-Smacking Reveals Putative Precursors of Speech Dynamics A key feature of speech is its stereotypical 5 Hz rhythm. One theory posits that this rhythm evolved through the modification of rhythmic facial movements in ancestral primates. If the hypothesis has any validity, then a comparative approach may shed some light. We tested this idea by using cineradiography (X-ray movies) to characterize and quantify the internal dynamics of the macaque monkey vocal tract during lip-smacking (a rhythmic facial expression) versus chewing. Previous human studies showed that speech movements are faster than chewing movements, and the functional coordination between vocal tract structures is different between the two behaviors. If rhythmic speech evolved through a rhythmic ancestral facial movement, then one hypothesis is that monkey lip-smacking versus chewing should also exhibit these differences. We found that the lips, tongue, and hyoid move with a speech-like 5 Hz rhythm during lip-smacking, but not during chewing. Most importantly, the functional coordination between these structures was distinct for each behavior. These data provide empirical support for the idea that the human speech rhythm evolved from the rhythmic facial expressions of ancestral primates.

negative: Discrimination of speech stimuli based on neuronal response phase patterns depends on acoustics but not comprehension. Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3-7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response.

negative: Autosomal dominant lateral temporal epilepsy: two families with novel mutations in the LGI1 gene. PURPOSE Mutations in the leucine rich, glioma inactivated gene (LGI1) were recently described in a small number of families with autosomal dominant lateral temporal epilepsy (ADLTE). ADLTE is characterized by partial seizures with symptoms suggestive of a lateral temporal onset, including frequent auditory aura. Here we report the results of clinical and genetic analyses of two newly identified families with ADTLE. METHODS We identified two families whose seizure semiology was suggestive of ADLTE. Evaluation included a detailed history and neurologic examination, as well as collection of DNA. The coding sequence of the LGI1 gene from affected subjects from both families was analyzed for evidence of mutation. RESULTS Each patient had a history of partial seizures, often with secondary generalization earlier in the course. Auditory aura was reported by approximately two thirds of affected patients in each pedigree. Novel mutations in LGI1 were detected in both families. A heterozygous single-nucleotide deletion at position 329 (del 329C) was detected in affected individuals from one family, whereas patients from the second family had a nonsynonymous variation, corresponding to C435G. CONCLUSIONS We identified two novel mutations in the LGI1 gene. The phenotype of these two families was similar to that of other kindreds with ADLTE, as auditory aura was absent in one third of affected individuals. Our results further support that LGI1 mutations should be considered in patients with a history of partial seizures if the semiology of seizures is consistent with the onset in the lateral temporal lobe.

negative: Converging Intracranial Markers of Conscious Access We compared conscious and nonconscious processing of briefly flashed words using a visual masking procedure while recording intracranial electroencephalogram (iEEG) in ten patients. Nonconscious processing of masked words was observed in multiple cortical areas, mostly within an early time window (<300 ms), accompanied by induced gamma-band activity, but without coherent long-distance neural activity, suggesting a quickly dissipating feedforward wave. In contrast, conscious processing of unmasked words was characterized by the convergence of four distinct neurophysiological markers: sustained voltage changes, particularly in prefrontal cortex, large increases in spectral power in the gamma band, increases in long-distance phase synchrony in the beta range, and increases in long-range Granger causality. We argue that all of those measures provide distinct windows into the same distributed state of conscious processing. These results have a direct impact on current theoretical discussions concerning the neural correlates of conscious access.

negative: The Neurobiology of Sleep: Genetics, cellular physiology and subcortical networks To appreciate the neural underpinnings of sleep, it is important to view this universal mammalian behaviour at multiple levels of its biological organization. Molecularly, the circadian rhythm of sleep involves interlocking positive- and negative-feedback mechanisms of circadian genes and their protein products in cells of the suprachiasmatic nucleus that are entrained to ambient conditions by light. Circadian information is integrated with information on homeostatic sleep need in nuclei of the anterior hypothalamus. These nuclei interact with arousal systems in the posterior hypothalamus, basal forebrain and brainstem to control sleep onset. During sleep, an ultradian oscillator in the mesopontine junction controls the regular alternation of rapid eye movement (REM) and non-REM sleep. Sleep cycles are accompanied by neuromodulatory influences on forebrain structures that influence behaviour, consciousness and cognition.

negative: Identifying common impairments in frail and dependent older people: validation of the COPE assessment for non-specialised health workers in low resource primary health care settings BACKGROUND Frail and dependent older people in resource-poor settings are poorly served by health systems that lack outreach capacity. The COPE (Caring for Older PEople) multidimensional assessment tool is designed to help community health workers (CHWs) identify clinically significant impairments and deliver evidence-based interventions   METHODS Older people (n = 150) identified by CHWs as frail or dependent, were assessed at home by the CHW using the structured COPE assessment tool, generating information on impairments in nutrition, mobility, vision, hearing, continence, cognition, mood and behaviour. The older people were reassessed by local physicians who reached a clinical judgment regarding the presence or absence of the same impairments based upon clinical examination guided by the EASY-Care assessment tool. RESULTS The COPE tool was considered easy to administer, and gave CHWs a sense of empowerment to understand and act upon the needs of older people. Agreement between COPE assessment by CHW and clinician assessors was modest (ranged from 45.8 to 91.3 %) for most impairments. However, the prevalence of impairments was generally higher according to clinicians, particularly for visual impairment (98.7 vs 45.8 %), cognitive impairment (78.4 vs. 38.2 %) and depression (82.0 vs. 59.9 %). Most cases identified by WHO-COPE were clinician confirmed (positive predictive values - 72.2 to 98.5 %), and levels of disability and needs for care among those identified by COPE were higher than those additionally identified by the clinician alone. CONCLUSIONS The COPE is a feasible tool for the identification of specific impairments in frail dependent older people in the community. Those identified are likely to be confirmed as having clinically relevant problems by clinicians working in the same service, and the COPE may be particularly effective at targeting attention upon those with the most substantial unmet needs.

negative: From youth to adult homelessness Governments have shown an interest in early intervention strategies to reduce youth homelessness, but critics say that early intervention programs lack clear outcomes. This paper investigates what happens when early intervention programs are not in place and young people progress to adult homelessness. The paper assesses the 'social adaptation' hypothesis that the longer young people are homeless the more they adapt to homelessness as a way of life. The paper uses information on 1,677 individuals who first became homeless when they were 18 or younger. Three-quarters of the sample had progressed to adult homelessness (defined as 25 or older) and one-quarter were now young adults aged 19 to 24. The findings confirm that the longer people are homeless, the more difficult it becomes to get out of homelessness. However, the social adaptation account overstates the extent to which people accept homelessness as a 'way of life'. People can return to conventional accommodation if they are given long-term support. The paper concludes with three policy recommendations.

negative: Cryptochromes Enabling Plants and Animals to Determine Circadian Time Cryptochromes are flavin-containing blue light photoreceptors related to photolyases-they are found in both plants and animals and have recently been described for bacteria. In plants, cryptochromes perform a variety of functions including the entrainment of circadian rhythms. They serve a similar role in Drosophila and mammals, where the cryptochromes also perform an additional function as an essential component of the circadian clock.

negative: Integration of mental health into primary healthcare in low-income countries: avoiding medicalization. Since 2008 the World Health Organization (WHO), through its mental health Gap Action Programme, has attempted to revitalize efforts to integrate mental health into non-specialized (e.g. primary) healthcare. While this has led to renewed interest in this potential method of mental health service delivery, it has also prompted criticism. Some concerns raised are that it would contribute to the medicalization of social and psychological problems, and narrowly focus on primary care without sufficient attention given to strengthening other levels of the healthcare system, notably community-based care and care on district levels. This paper discusses seven elements that may be critical to preventing inadvertently contributing to increasing a narrow biomedical approach to mental healthcare when integrating mental health into non-specialized healthcare: (1) using task shifting approaches within a system of stepped care, (2) ensuring primary mental healthcare also includes brief psychotherapeutic interventions, (3) promote community-based recovery-oriented interventions for people with disabling chronic mental disorders, (4) conceptualizing training as a continuous process of strengthening clinical competencies through supervision, (5) engaging communities as partners in psychosocial interventions, (6) embedding shifts to primary mental healthcare within wider health policy reforms, and (7) promoting inter-sectoral approaches to address social determinants of mental health.

negative: A transition in brain state during propofol-induced unconsciousness. Rhythmic oscillations shape cortical dynamics during active behavior, sleep, and general anesthesia. Cross-frequency phase-amplitude coupling is a prominent feature of cortical oscillations, but its role in organizing conscious and unconscious brain states is poorly understood. Using high-density EEG and intracranial electrocorticography during gradual induction of propofol general anesthesia in humans, we discovered a rapid drug-induced transition between distinct states with opposite phase-amplitude coupling and different cortical source distributions. One state occurs during unconsciousness and may be similar to sleep slow oscillations. A second state occurs at the loss or recovery of consciousness and resembles an enhanced slow cortical potential. These results provide objective electrophysiological landmarks of distinct unconscious brain states, and could be used to help improve EEG-based monitoring for general anesthesia.


query: Functional consequences of genomic alterations due to Myelodysplastic syndrome (MDS) are poorly understood due to the lack of an animal model.

positive: Establishment of human iPSC-based models for the study and targeting of glioma initiating cells Glioma tumour-initiating cells (GTICs) can originate upon the transformation of neural progenitor cells (NPCs). Studies on GTICs have focused on primary tumours from which GTICs could be isolated and the use of human embryonic material. Recently, the somatic genomic landscape of human gliomas has been reported. RTK (receptor tyrosine kinase) and p53 signalling were found dysregulated in ∼90% and 86% of all primary tumours analysed, respectively. Here we report on the use of human-induced pluripotent stem cells (hiPSCs) for modelling gliomagenesis. Dysregulation of RTK and p53 signalling in hiPSC-derived NPCs (iNPCs) recapitulates GTIC properties in vitro. In vivo transplantation of transformed iNPCs leads to highly aggressive tumours containing undifferentiated stem cells and their differentiated derivatives. Metabolic modulation compromises GTIC viability. Last, screening of 101 anti-cancer compounds identifies three molecules specifically targeting transformed iNPCs and primary GTICs. Together, our results highlight the potential of hiPSCs for studying human tumourigenesis.

negative: T cell memory. T cell memory induced by prior infection or vaccination provides enhanced protection against subsequent microbial infections. The processes involved in generating and maintaining T cell memory are becoming better understood due to recent technological advances in identifying memory T cells and monitoring their behavior and function in vivo. Memory T cells develop in response to a progressive set of cues-starting with signals from antigen-loaded, activated antigen-presenting cells (APCs) and inflammatory mediators induced by the innate immune response, to the poorly defined subsequent signals triggered as the immune response wanes toward homeostasis. The persistence of the resting memory T cells that eventually develop is regulated by cytokines. This chapter discusses recent findings on how memory T cells develop to confer long-term protective immunity.

negative: A prospective natural-history study of coronary atherosclerosis. BACKGROUND Atherosclerotic plaques that lead to acute coronary syndromes often occur at sites of angiographically mild coronary-artery stenosis. Lesion-related risk factors for such events are poorly understood. METHODS In a prospective study, 697 patients with acute coronary syndromes underwent three-vessel coronary angiography and gray-scale and radiofrequency intravascular ultrasonographic imaging after percutaneous coronary intervention. Subsequent major adverse cardiovascular events (death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization due to unstable or progressive angina) were adjudicated to be related to either originally treated (culprit) lesions or untreated (nonculprit) lesions. The median follow-up period was 3.4 years. RESULTS The 3-year cumulative rate of major adverse cardiovascular events was 20.4%. Events were adjudicated to be related to culprit lesions in 12.9% of patients and to nonculprit lesions in 11.6%. Most nonculprit lesions responsible for follow-up events were angiographically mild at baseline (mean [±SD] diameter stenosis, 32.3±20.6%). However, on multivariate analysis, nonculprit lesions associated with recurrent events were more likely than those not associated with recurrent events to be characterized by a plaque burden of 70% or greater (hazard ratio, 5.03; 95% confidence interval [CI], 2.51 to 10.11; P<0.001) or a minimal luminal area of 4.0 mm(2) or less (hazard ratio, 3.21; 95% CI, 1.61 to 6.42; P=0.001) or to be classified on the basis of radiofrequency intravascular ultrasonography as thin-cap fibroatheromas (hazard ratio, 3.35; 95% CI, 1.77 to 6.36; P<0.001). CONCLUSIONS In patients who presented with an acute coronary syndrome and underwent percutaneous coronary intervention, major adverse cardiovascular events occurring during follow-up were equally attributable to recurrence at the site of culprit lesions and to nonculprit lesions. Although nonculprit lesions that were responsible for unanticipated events were frequently angiographically mild, most were thin-cap fibroatheromas or were characterized by a large plaque burden, a small luminal area, or some combination of these characteristics, as determined by gray-scale and radiofrequency intravascular ultrasonography. (Funded by Abbott Vascular and Volcano; ClinicalTrials.gov number, NCT00180466.).

negative: Metabolic syndrome as a risk factor for diabetes. The metabolic syndrome was initially described as an insulin-resistance syndrome characterized by the clustering of metabolic traits such as high triglycerides, low high-density lipoprotein cholesterol, high blood pressure, abdominal obesity and different degrees of impaired glucose regulation. Although different definitions have been developed by various consensus groups, epidemiological studies demonstrate that they all associate the metabolic syndrome with a similar cardiometabolic risk, which is high for diabetes (ranging between three- and 20-fold), depending on the number of components and the inclusion of impaired fasting glucose, impaired glucose tolerance or both. The latter appear to indicate the failure of the beta cell to produce enough insulin to compensate for the increased demand due to insulin resistance. There is a hyperbolic relationship between insulin production and insulin sensitivity, which can be calculated by the disposition index. When this is altered there is a higher risk of developing Type 2 diabetes. There have been no clinical trials in subjects selected by the diagnosis of metabolic syndrome, but structured lifestyle changes have been tested in people with impaired fasting glucose/impaired glucose tolerance and have been able to reduce incident Type 2 diabetes by almost 50%, as long as a weight loss of at least 5% is achieved. Oral antidiabetic and anti-obesity drugs have also been successful to a lesser degree. Some fibrates have reduced or delayed incident diabetes. Extended-release niacin has a neutral effect and statins are controversial. ACE inhibitors and ARBs are the antihypertensive agents least associated with incident diabetes.

negative: Survival in a case of massive paraquat ingestion. Serious exposure to the herbicide paraquat usually results in death, either due to gastrointestinal caustic lesions, shock, and acute respiratory distress syndrome or related to the progressive development of pulmonary fibrosis associated with refractory hypoxemia. We report a case of suicidal paraquat ingestion in a 59-year-old man. Most of the indicators of poor prognosis were encountered in this patient. Treatment consisted of early digestive decontamination and hemodialysis, followed by antioxidant therapy, including the administration of deferoxamine (100 mg/kg in 24 h) and a continuous infusion of acetylcysteine (300 mg/kg/d during 3 weeks). The patient only developed a nonoliguric acute renal failure, a mild alteration of liver tests, and an impairment of CO transfer factor without any respiratory complaint. Renal and hepatic disturbances completely resolved within 1 month, whereas CO transfer factor remained altered 14 months later. This observation suggests that early administration of an antioxidant therapy, including deferoxamine and acetylcysteine could be usefully associated with measures that prevent digestive absorption or enhance elimination to limit systemic toxicity in potentially fatal paraquat poisoning.

negative: PP2A regulates tau phosphorylation directly and also indirectly via activating GSK-3beta. Abnormal hyperphosphorylation of tau appears to be crucial in neurofibrillary degeneration in Alzheimer's disease (AD). Previous studies suggest that a down-regulation of protein phosphatase 2A (PP2A), the major tau phosphatase in human brain, contributes to tau hyperphosphorylation in AD. However, the effects of PP2A down-regulation on site-specific tau hyperphosphorylation is not well understood. In the present study, we showed that PP2A dephosphorylated tau at several phosphorylation sites with different efficiencies. Among the sites studied, Thr205, Thr212, Ser214, and Ser262 were the most favorable sites, and Ser199 and Ser404 were the least favorable sites for PP2A in vitro. Inhibition of PP2A with okadaic acid in metabolically active rat brain slices caused inhibition of glycogen synthase kinase-3beta (GSK-3beta) via an increase in its phosphorylation at Ser9. GSK-3beta phosphorylated tau at many sites, with Ser199, Thr205, and Ser396 being the most favorable sites in cells. The overall alterations in tau phosphorylation induced by PP2A inhibition were the result of the combined effects of both reduced tau dephosphorylation due to PP2A inhibition directly and reduced phosphorylation by GSK-3beta due to its inhibition. Because the impacts of tau phosphorylation on its biological activity and on neurofibrillary degeneration are site-specific, this study provides a new insight into the role of PP2A down-regulation in neurofibrillary degeneration in AD.

negative: Catch and release: how do kinetochores hook the right microtubules during mitosis? Sport fishermen keep tension on their lines to prevent hooked fish from releasing. A molecular version of this angler's trick, operating at kinetochores, ensures accuracy during mitosis: the mitotic spindle attaches randomly to chromosomes and then correctly bioriented attachments are stabilized due to the tension exerted on them by opposing microtubules. Incorrect attachments, which lack tension, are unstable and release quickly, allowing another chance for biorientation. Stabilization of molecular interactions by tension also occurs in other physiological contexts, such as cell adhesion, motility, hemostasis, and tissue morphogenesis. Here, we review models for the stabilization of kinetochore attachments with an eye toward emerging models for other force-activated systems. Although attention in the mitosis field has focused mainly on one kinase-based mechanism, multiple mechanisms may act together to stabilize properly bioriented kinetochores and some principles governing other tension-sensitive systems may also apply to kinetochores.

negative: Exercise as a therapeutic approach to improve blood pressure in patients with peripheral arterial disease: current literature and future directions. INTRODUCTION Patients with symptomatic peripheral artery disease (PAD) exhibit reduced functional capacity and increased mortality due to cardiovascular disease. Although exercise has been a cornerstone for clinical treatment to improve walking capacity in patients with symptomatic PAD, its effects on cardiovascular parameters have been poorly explored. Areas covered: This review examines the role of exercise in improving blood pressure in patients with symptomatic PAD and summarizes the current evidence on the acute (single bout of exercise) and chronic effects of walking and resistance exercise on blood pressure and its determinants. Expert commentary: In patients with symptomatic PAD, exercise promotes acute and chronic reductions in blood pressure. These effects were observed particularly after walking and resistance exercise. Future studies are necessary to investigate the effects of other exercise modalities, especially non-painful exercises, on cardiovascular function in patients with symptomatic PAD.

negative: The history of SIVS and AIDS: epidemiology, phylogeny and biology of isolates from naturally SIV infected non-human primates (NHP) in Africa. Simian immunodeficiency virus (SIV) naturally infects non-human primates in Africa. To date, 40 SIVs have been described both in natural hosts and in heterologous species. These viruses are highly diverse and the majority cluster in 6 relatively equidistant phylogenetic lineages. At least 8 SIVs are currently considered as recombinant viruses, based on different clustering patterns in different genomic regions. Only three types of genomes are known, based on the number of accessory genes: vpr-containing genomes, vpr-vpx containing genomes and vpr-vpu-containing genomes. vpx resulted by a duplication of the vpr gene following non-homologous recombination and is characteristic of SIVs infecting the Papionini tribe of monkeys and HIV-2 in humans. vpu is characteristic of SIVcpz and HIV-1 and may have originated from a recombination involving SIVs from cercopitecini monkeys. SIV seems to be non-pathogenic in the vast majority of natural hosts in spite of a high levels of viral replication. This is probably a consequence of virus-host adaptation, in which the incubation period of the disease generally exceeds the life span of the African primate host. SIVs also have a high propensity for cross-species transmission. In the new host, the outcome may vary from inapparent infection to highly pathogenic, the former being reported for African monkeys, whereas the latter being observed in macaques and humans. The high diversity of SIVs was generated by a high mutation rate due to a low fidelity of the reverse-transcriptase and active viral and host cell turnover, host-dependent evolution and recombination. Cross-species transmission is not rare, however preferential host switching may drive the majority of cross-species transmissions. Numerous SIVs tested so far are able to grow in vitro on human PBMC, therefore it has been postulated that SIV represents a threat for infection of humans in Central Africa and that AIDS is a zoonosis. However, although the simian origin of the two HIV types is broadly acknowledged, there are no data that AIDS is acquired like a zoonosis. SIV may undergo adaptation in the new human host in order to emerge in the general population. The study of SIV in their natural hosts should provide important clues to the real threat to human populations and also elucidate the mechanisms associated with a long-term persistent viral infection without clinical consequences for the host.

negative: Dealing with substantial heterogeneity in Cochrane reviews. Cross-sectional study BACKGROUND Dealing with heterogeneity in meta-analyses is often tricky, and there is only limited advice for authors on what to do. We investigated how authors addressed different degrees of heterogeneity, in particular whether they used a fixed effect model, which assumes that all the included studies are estimating the same true effect, or a random effects model where this is not assumed. METHODS We sampled randomly 60 Cochrane reviews from 2008, which presented a result in its first meta-analysis with substantial heterogeneity (I2 greater than 50%, i.e. more than 50% of the variation is due to heterogeneity rather than chance). We extracted information on choice of statistical model, how the authors had handled the heterogeneity, and assessed the methodological quality of the reviews in relation to this. RESULTS The distribution of heterogeneity was rather uniform in the whole I2 interval, 50-100%. A fixed effect model was used in 33 reviews (55%), but there was no correlation between I2 and choice of model (P = 0.79). We considered that 20 reviews (33%), 16 of which had used a fixed effect model, had major problems. The most common problems were: use of a fixed effect model and lack of rationale for choice of that model, lack of comment on even severe heterogeneity and of reservations and explanations of its likely causes. The problematic reviews had significantly fewer included trials than other reviews (4.3 vs. 8.0, P = 0.024). The problems became less pronounced with time, as those reviews that were most recently updated more often used a random effects model. CONCLUSION One-third of Cochrane reviews with substantial heterogeneity had major problems in relation to their handling of heterogeneity. More attention is needed to this issue, as the problems we identified can be essential for the conclusions of the reviews.

negative: Golgi Export of the Kir2.1 Channel Is Driven by a Trafficking Signal Located within Its Tertiary Structure Mechanisms that are responsible for sorting newly synthesized proteins for traffic to the cell surface from the Golgi are poorly understood. Here, we show that the potassium channel Kir2.1, mutations in which are associated with Andersen-Tawil syndrome, is selected as cargo into Golgi export carriers in an unusual signal-dependent manner. Unlike conventional trafficking signals, which are typically comprised of short linear peptide sequences, Golgi exit of Kir2.1 is dictated by residues that are embedded within the confluence of two separate domains. This signal patch forms a recognition site for interaction with the AP1 adaptor complex, thereby marking Kir2.1 for incorporation into clathrin-coated vesicles at the trans-Golgi. The identification of a trafficking signal in the tertiary structure of Kir2.1 reveals a quality control step that couples protein conformation to Golgi export and provides molecular insight into how mutations in Kir2.1 arrest the channels at the Golgi.