In young chicks intrahypothalamic infusion of cholera toxin produced a dramatic and dose-dependent increase in motor activity. Similar effects were also obtained in adult fowls after injection of cholera toxin into the third cerebral ventricle, the hypothalamus or the paleostriatum augmentatum. Electrocortical changes consisted of a slight desynchronization during the hypermotor activity and were preceded, when the highest intraventricular doses were used, by a short period of slower frequency and higher amplitude potentials. Intraventricular and intrahypothalamic but not intrastriatal injection of cholera toxin produced a typical biphasic hyperthermic response.