Bilateral activity and callosal connections in the somatosensory cortex

Earlier studies recording single neuronal activity in the postcentral somatosensory cortex of monkeys converged in suggesting that the bilateral receptive fields were related exclusively to the body midline including the trunk, perioral face, and oral cavity. These neurons were recorded mostly in the rostral part of the gyrus, areas 3b and 1. However, the authors recently found a substantial number of neurons with bilateral receptive fields on extremities, hand/digits, shoulders/arms, or legs/feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus. The authors review these results and discuss functional implications of the bilateral representation in the postcentral somatosensory cortex.