[Electrical activity of layers of isolated cortex during drowsiness and different sleep stages].

In cats with isolated cerebral cortex, with the aid of electordes indwelled into different cortical layers, first electrographic changes during onset of sleep were shown to occur, as with intact cortex, in the lower layers of the isolated cortex. 3-4 months after the cortex isolation, changes of electrical activity during sleep occured simultaneously in the cortex of both hemispheres. Awakening produced desynchronization of electrical activity in all cortical layers of both hemispheres. Origin of primary electrical activity changes in the lower cortical layers, is discussed.