Motor effects produced by stimulation of secondary somatosensory (SII) cortex in the monkey

Threshold for evoking movements by microstimulation of the second somatosensory area of the cynomolgus monkey's cortex to intracortical microstimulation was examined. Motor effects were obtained contralateral to the side of stimulation, in a region histologically verified to be in grey matter deep in the sylvian cortex, and which corresponds to the second somatosensory cortex. The thresholds were low but higher than for movements evoked by stimulation of the motor cortex. The results are explained in terms of increased specialization of the motor cortex for movements in the monkey compared with the cat.