21 Pages

Transitional Phases Between the Animal’s Waking and Complete Sleep (Hypnotic Phases)31

WithIvan P. Pavlov

In this chapter, the author investigates the relation of conditioned reflexes under the effect of hypnotics from the beginning of this effect to the complete lapse of an experimental animal into sleep and the reverse, to the animal’s return to the waking state. The investigation shows that during the development of the hypnotic effect all the stimuli gradually lost their effect, whereas during the return to the waking state all of them also gradually regained their normal effect. Using extensive experimental material, the author sets forth the basic regularities observed in the transitional states from waking to sleep, regularities concerning the spread and depth of the processes of inhibition in the cerebral cortex, and data on different extent and intensity of sleep.