A behavioral study of the functions of the rolandic cortex in the monkey

The signticance of the primate Rolandic fissure remains a subject of controversy despite extensive experimental analyses. Before the turn of the century many investigators regarded the entire Rolandic cortex as a‘’ sensorimotor” uni~ but early in this century the dominant viewpoint shifted toward a sharp demarcation of the precentral “motor” and postcentral” sensory” cortex. Recently, as a result of electrophysiological investigations, the emphasis has begun to swing back toward the nineteenth century conception. Electrical stimulation of the cortex with recording of the consequent muscular contractions has revealed that a pattern comparable to that described for the precentral gyrus can be determined for the postcentral gyrus in the monkey (Woolsey et al., ’53). Electrical excitation of peripheral nerves or of dorsal roots has been shown to elicit electrical responses which can be evoked in the precentral as well as the postcentral gyrus (Woolsey, Chang and Bard) ’47; Ruth, Patton and Amassian, ’52; Malis, Pribram and Kruger, ’53; Gardner and Morin, ’53; Adey, Porter and Carter, ’54; and 1Unitd States PubBc Health Service Postdoctoral FeUow. ‘ Present Address: Centre d ‘Etudes de Physiologic nerveuse et d ‘Electrophysiologie, 4 Avenue Gordon Bemett, Paris 16, France. “ Support4 by Grant h’o. DA-49-007-MD-401 of the Department of the Amy. ,,-.,,. : %,,.,