Thalamic Oscillation
The thalamocortical loop starts with oscillatory thalamic cells. These cells receive both sensory input from the body as well as input from feedback pathways in the brain. In a sense, these cells serve to integrate these multiple inputs by changing their inherent oscillatory properties in response to depolarization by these many different inputs. TC neurons exhibit gamma oscillation when depolarized to greater than -45 mV, and the frequency of oscillation is related to the degree of depolarization. This oscillation is caused by the activation of leaky P/Q-type calcium channels found in the dendrites of the cells. Because of the leaky channel properties, spontaneous, inherent oscillation can also occur independent of any rhythmic input as well, though the ramifications of this capability are not entirely known and may add nothing but background noise to the thalamocortical loop.
The cortex provides feedback to the thalamus through links to dendrites of these thalamocortical cells and serves as the source of constant thalamic oscillation. Oscillatory behavior depends on the conscious/unconscious state of the brain. During active thinking, electroencephalography reveals a strong appearance of gamma range oscillation from around 20–50 Hz.
Read more about this topic: Recurrent Thalamo-cortical Resonance
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