ORGANIZATION OF CALLOSAL CONNECTIONS IN SUPRASYLVIAN GYRUS OF CAT

Abstract

In the unanesthetized cerebral cortex, spontaneous activity becomes intermittent after subpial section of the cortical radiations. Stimulation of one hemisphere during the silent intervals gives rise to a transcallosal response consisting of a focal positive-negative evoked response lasting about 50 msec, followed by a spreading burst of activity. Experiments involving stimulation at different depths in the cortex, application of procaine to the stimulated point, initiation of spreading depression near the stimulated point, and double-shock stimulation, indicate that callosal fibers originating in neurones near the surface of the cortex in one hemisphere end near the surface of the cortex on the other side, while those originating in deep-lying neurons end in the deep cortical layers on the other side.