Electrical activity of the human brain during artificial sleep. I. The cyclical pattern of response to barbiturate sedation.

A wide variety of special techniques is now employed in clinical electroencephalography (Kaufman and Watson, 1949) to unmask latent abnormalities in cerebral electrical activity. One of the most useful of these is clinical and electrical observation of the patient while asleep (Gibbs and Gibbs, 1941, 1947; Wyke, 1949), and this provides information of physiological as well as of direct clinical interest. As observations during natural sleep are inconvenient, artificial methods of sleep induction have been sought, and such various substances as paraldehyde, sodium amytal, " nembutal," sodium pentothal, sodium evipan, and seconal sodium have been employed to this end. The most satisfactory agent for this purpose in our hands is seconal sodiumt, suggested by Gibbs and Gibbs (1949), and our experience with it now embraces 100 cases. On the basis of this experience the present communication discusses the cyclical changes that this agent induces in the human electroencephalogram. It is restricted to the normal physiological changes. The technique for clinical testing and the abnormal variations are discussed elsewhere.