A study of the excitability of the hypothalamic region of the brain of the cat following bilateral degeneration of corticifugal connections from the frontal lobes, showed a considerable loss of excitability for vasodepressor and respiratory inhibitory effects. Contractions of the urinary bladder, pupillary dilatation, retraction of the nictitating membrane, vasopressor responses and respiratory excitatory effects, including faciovocal activity, were elicited just as in animals with intact brains.