A neural substrate for affiliative behavior in nonhuman primates.

Studies of social behavior following localized brain lesions in several species of Old World monkeys suggest there is an anatomical substrate for the maintenance of social bonds. Destruction of either the amygdaloid nuclei, orbital frontal cortex or temporal pole results in varying degrees of social isolation or marked reductions in affiliative behaviors depending upon the environmental and social setting. The relationship between the loss of affiliative behaviors subsequent to these lesions and other functions previously demonstrated to be represented in these neural structures is discussed.