The indirect route | Neuro-patch
There has been a bit of mystery around how different areas of the cortex initiate shared synchrony or seem to pass information between them. A paper from a few years back (Poulet, Fernandez, Crochet, Peterson; Thalamic control of cortical states; Nature 2012) showed that the activity of the whiskers of mice affected the state of activity in the cortex. How did the whiskers affect the whole cortex rather than just the whisker sensory area? It was via the thalamus shown by producing the effect without whisker activity by stimulation of thalamus alone. "We investigated the impact of thalamus on ongoing cortical activity in the awake, behaving mouse. We demonstrate that the desynchronized cortical state during active behavior is driven by a centrally generated increase in thalamic action potential firing, which can also be mimicked by optogenetic stimulation of the thalamus. The thalamus therefore is key in controlling cortical states." But that was a very general demonstration of