Postcentral neurons of alert monkeys activated by the contact of the hand with objects other than the monkey's own body.

In the caudal postcentral finger region near or in the anterior bank of the intraparietal sulcus of alert monkeys, we found neurons that were activated selectively by the contact of the hand to certain common objects such as bottle brushes, acrylic plates, parts of the stabilized monkey's chair, etc. All of these neurons were not activated when the monkey's hand was contacted with the monkey's own body. We concluded that these neurons are concerned with the haptic discrimination of common objects with the selectivity to one of various material variables of objects, and that the process involves differentiation of the object from the animal's own body.