RESPONSES TO LATERAL GENICULATE RADIATION STIMULATION IN CATS WITH IMPLANTED ELECTRODES

Abstract

Cats with electrodes permanently implanted in the lateral geniculate radiations and on the surface of the lateral gyrus were studied during the waking state and under pentobarbital anesthesia. Stimuli delivered to the geniculate radiations evoked a primary cortical response which was recorded from the lateral gyrus. The configuration of the cortical response evoked by a single radiation stimulus in unanesthetized intact preparations is generally similar to that of the response evoked in animals anesthetized with pentobarbital. The early phase (first 25 mseconds) of the recovery cycle of the cortical response is markedly depressed by pentobarbital, though final recovery time is not prolonged by this drug. A number of observations indicate that the 3d spike (C-3) of the cortical response does not represent activity in geniculate radiation fibers. Intact preparations with chronically implanted electrodes are suitable for studies of the responses evoked by synchronous activation of thalamocortical afferents.