UNCUS AND AMYGDALA LESIONS - EFFECTS ON SOCIAL BEHAVIOR IN FREE-RANGING RHESUS MONKEY

The effect of uncinectomy on the social behavior of free-ranging rhesus monkeys was observed on Cayo Santiago Island. Operated subjects showed social indifference, failed to display appropriate aggressive and submissive gestures, were expelled from their social group, and eventually died. Two juvenile subjects with the lesion restricted to amygdala survived and have rejoined their social group. Size of lesion and age at operation were major factors in determining the degree of behavioral change.