Evoked potential study of the synchronizing and hypnogenic areas in the basal forebrain.

On stimulating various basal forebrain structures, characteristic cortical evoked potentials, basic elements of the synchronization elicited, were studied in acute immobilized cats. Stimulation of the LH/10 cps/ resulted in short latency positive-negative evoked potentials, similar responses of increased latency were elicited from the RPO and TbOf. The laterobasal RPO and TbOf, the only areas able to induce cortical synchronization upon high frequency stimulation, could be clearly distinguished on the basis of evoked potentials. The laterobasal RPO was characterized by short latency, long-lasting positive potentials, while stimulation of TbOf elicited negative-positive responses. The relationship between the evoked potentials and the synchronizing mechanism of the basal forebrain is discussed.