Disruption of appetite but not hunger or satiety following small lesions in the amygdala of rats.

Discretely localized lesions were made in the amygdala to examine how specifically they might alter various measures of feeding behavior in male rats. Behavioral tests included spontaneous intake and body weight regulation, reactivity to saccharin and quinine solutions, conditioned taste aversion, the feeding response to food deprivation, the response to glucose gavage, and teh response to dietary amino acid imbalance. Lesions in virtually all regions of the amygdala disrupted feeding behavior in some respect, but alterations in specific tasks were associated only with highly circumscribed brain damage. Body weight regulation, spontaneous food and water intake, and the responses to glucose gavage and long-term food deprivation were not altered by lesions in the amygdala. The results provide evidence that, in the rat, the amygdala may play a greater role in appetite than in hunger or safety. In particular, amygdaloid nuclei may participate in maintaining a negative bias in the reactivity to all appetitive stimuli.