Effect of Hypothalamic Lesions on the Amygdala Syndrome in the Cat

This work has shown that the ventromedial nucleus of the hypothalamus appears to be a strong recipient of fibers arising from the amygdaloid complex, and has given rise to changes in behavior characterized by savage and aggressive attacks on other animals when approached, obesity, and hyposexual activity.

Abstract

Introduction Previous studies have shown that bilateral ablation of the amygdaloid nuclei and surrounding rhinencephalic structures in rodents, carnivores, and primates is uniquely characterized by a specific pattern of behavior. Animals sustaining such lesions exhibit behavior that is dominated by increased responsiveness to visual stimuli, hyperactivity, exaggerated oral activity, inability to recognize objects visually, loss of fear, and an increase in amount and diversity of sexual behavior. 6,14-16,18-21,24 Anatomical and electrophysiological studies of the amygdaloid nucleus and related structures have revealed efferent projections from the amygdala to widespread areas of the cortex and subcortex. 1,8-11 More specifically, the ventromedial nucleus of the hypothalamus appears to be a strong recipient of fibers arising from the amygdaloid complex. Electrolytic lesions of the ventromedial nucleus in cats and rats 2,12,23 have given rise to changes in behavior characterized by savage and aggressive attacks on other animals when approached, obesity, and hyposexual activity. In