Recovery cycle of visual cortex of the awake and sleeping cat

¹ Laboratories of Neurophysiology and Clinical Science, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland

Cats with chronically implanted electrodes were employed in studies of the effects of sleep and waking on the recovery cycle of the cortical response to electrical stimulation of lateral geniculate radiations. Identical test and conditioning stimuli were delivered to the geniculate radiations at intervals of 3.2–1000 msec. At intervals between 16 and 200 msec., the subnormality of the test response was more marked during waking than during sleep. Amplitude of responses to single stimuli was greater during sleep than during waking. The results are discussed in relation to the hypothesis that there is an increase in the activity of inhibitory processes in the visual cortex during waking.