Activity of the layer II/III neurons in the somatosensory cortex (SSC) plays a critical role on functional recovery after focal stroke in the contralateral SSC

Optimal functional recovery after stroke is the most important to improve quality of life. Contralateral hemisphere of infarction site plays an important role for the recovery. The underlying processes in contralateral hemisphere during recovery have not yet been fully elucidated. We have previously reported the increase in synaptic turnover in the contralateral somatosensory cortex (SSC) during 1st week after infarction of the unilateral SSC. The neuronal circuit was remodeled after this period to process bilateral information in the remaining hemisphere, and functional compensation was achieved. In the present study, we used in vivo electrophysiological recording to detect the current source density (CSD) for somatosensory input. Interestingly, a specific CSD pattern was detected in the layer II/III region of contralateral SSC and the duration was significantly correlated with functional recovery. These results indicate that the compensational remodeling of neuronal circuit in the intact hemisphere may be dominantly induced in layer II/III neurons.