Grooming in the rat as an aftereffect of lateral hypothalamic stimulation

Grooming occurred as an aftereffect of electrical stimulation at hypothalamic sites that elicited locomotion, drinking, or eating as stimulus-bound behaviors. Removal of food or water, which caused rats to switch from one stimulus-bound behavior to another, produced little or no change in the grooming aftereffect. Stimulation with pulse showed that the absolute refractory period for the neurons responsible for the occurrence of grooming is approximately 1 msec. This value is longer than those reported for drinking, eating, and locomotion. Finally, it was found that with some electrodes, low levels of stimulation elicited grooming directly, during the stimulation; at higher levels grooming occurred only as an aftereffect. It is concluded that grooming is activated through neurons separate from those that produce drinking, eating, or locomotion and that its occurrence as an aftereffect may be due to an interaction between short-lasting inhibitory and longer lasting excitatory effects of the stimulation.