Hypothalamic knife cuts: Effects on eating, drinking, irritability, aggression, and copulation in the male rat

Describes 2 experiments with a total of 43 male hooded rats. In Exp. I, Ss with parasagittal knife cuts that separated the medial from the lateral hypothalamic areas (a) became hyperphagic, hyperdipsic, obese, and irritable; (b) did not change their level of aggressive responses against mice; and (c) copulated at an impaired rate or not at all. In Exp. II, 2 groups of Ss were subjected to coronal cuts restricted between the fornices at levels either anterior or posterior to the ventromedial hypothalamic nuclei. Most of the anterior-cut Ss increased their food and water intake, and some became irritable. Of the posterior-cut Ss, none increased and 1/2 decreased their food intake, some became hyperdipsic, and 1 became irritable. Neither of the coronal-cut groups changed levels of aggressive or sexual responses. It is concluded that the mediolateral hypothalamic connections are important for eating, irritability, and copulation. (42 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1972 American Psychological Association.