their formation occurs only when the cortical white matter afferents are stimulated at the gamma frequency range, implying an association with task-focused thought. The regions of inactive cortex that form between cortical columns were determined to be actively inhibited; administration of a GABAA blocker stops columnar development. Temporal binding Thalamocortical resonance is thought to be a potential explanation for coherence of perception in the brain. Temporal coincidence could occur through this mechanism by the integration of both specific and non-specific thalamic nuclei at the pyramidal cortical cell, as they both synapse on its apical dendrites. Feedback from the cortical cell back to the thalamic nuclei then relays the integrated signal. As there are numerous thalamocortical loops throughout the cortex, this process takes place simultaneously across many different regions of the brain during conscious perception. It is this ability to support large-scale synchronized events between remote brain regions that may provide for coherent perception. Altogether, the specific, ventrobasal neurons in the thalamus serve to introduce sensory input to a self-sustained feedback loop that is sustained by the non-specific, centrolateral TCs relaying information about the current cognitive state of the brain. Relation to brain activity Thalamocortical oscillation is thought to be responsible for the synchronization of neural activity between different regions of the cortex and is associated with the appearance of specific mental states depending on the frequency range of the most prominent oscillatory activity, gamma most associated with conscious, selective concentration on tasks, learning (perceptual and associative), and short-term memory. Magnetoencephalography (MEG) has been used to show that during conscious perception, gamma-band frequency electrical activity and thalamocortical resonance prominently occurs in the human brain. Absence of these gamma-band patterns correlates with nonconscious states and is characterized by the presence of lower-frequency oscillations instead. Vision The lateral geniculate nucleus, known as the major relay center from the sensory neurons in the eyes to the visual cortex, is found in the thalamus and has thalamocortical oscillatory properties, forming a feedback loop between the thalamus and the visual cortex. Sensory input can be seen to modulate the oscillatory patterns of thalamocortical activity while awake. In the case of vision, stimulation from light sources can be seen to cause direct changes in the amplitude of the thalamocortical oscillations as measured by EEG. Sleep Gamma wave thalamocortical oscillation is prominent during REM sleep, similar to the awakened, active brain. Contrary to the conscious state, however, it