Rhythmic activity of the brain evoked by local injections of carbachol into subcortical nuclei.

The effect of local injections of carbachol into the caudate nucleus and individual nuclei of the thalamus on the electrocorticogram of the anterior portion of the brain was investigated in unanesthetized, immobilized cats. It was shown that chemical stimulation of subcortical structures, like electrical stimulation, can induce spindle-like activity and a recruitment response. The appearance of these reactions after injections of carbachol both into the caudate nucleus and into individual nuclei of the thalamus indicates the existence of a functionally unified caudate-thalamic cholinoreceptive system, responsible for the slow wave rhythmic activity.