TEMPORAL-LOBE LESION-INDUCED OBESITY IN RATS - AN ANATOMICAL INVESTIGATION OF THE POSTERIOR AMYGDALA AND HIPPOCAMPAL-FORMATION

Bilateral lesions centered in the posterodorsal amygdala of female rat s resulted in hyperphagia and excessive weight gain (mean = 65.3 g in 20 days compared to 6.8 g for control animals). The brain damage alway s extended posteriorly into the ventral hippocampal formation. However , lesions that were confined to the ventral hippocampus or amygdalohip pocampal area had no effect on daily food intake or body weight, nor d id lesions at any other hippocampal site. In a previous study, lesions of the basolateral, corticomedial, and anterior groups of amygdaloid nuclei failed to affect food intake or body weight. It is concluded th at the posterodorsal aspect of the amygdala is the critical site for t his experimentally induced obesity syndrome. New coordinates for the e ffective site are presented.