Effects of bilateral lesions of the frontal granular cortex on the social behavior of rhesus monkeys.

Abstract

Eleven monkeys with bilateral lesions of the frontal granular cortex and 11 matched controls were observed during pairings with each of 12 stimulus monkeys. The frontal subjects were more withdrawn and distressed than the control animals. The operated animals showed less proximity and contact with the stimulus animals, directed less exploration toward the inanimate environment, and displayed more fear grimacing, screeching, and other disturbance behaviors. The stimulus animals, in turn, interacted less with the frontal monkeys than with the controls. They spent less time near the operated animals, and less frequently mounted and presented to them. Overall, the operated subjects directed more challenges toward the male stimulus animals, threatening them more than was appropriate for the circumstances, although levels of overt physical aggression were no higher, and in some cases depressed, in the monkeys with frontal lesions.

Context–specific social behavior is altered by orbitofrontal cortex lesions in adult rhesus macaques

“…Most nonhuman primate studies to date support the general conclusion that the orbitofrontal cortex is critical for species-typical social behavior (Deets et al, 1970, Snyder, 1970, Franzen and Myers, 1973, Myers et al, 1973, Machado and Bachevalier, 2006). Across published studies, however, the patterns of social behavior vary depending on social setting, social rank and size of lesion.…”

Social Cognition and the Prefrontal Cortex

“…Lesions of orbitofrontal cortex in oldworld monkeys have been shown to result in increased (Raleigh, Steklis, Ervin, Kling, & McGuire, 1979) and decreased (Butter & Snyder, 1972) aggression toward human observers. The data regarding aggression toward other monkeys following orbitofrontal lesions are equally mixed with some studies suggesting increased (Butter & Snyder, 1972) and others decreased aggression (Bowden, Goldman, & Rosvold, 1971;Deets, Harlow, Singh, & Blomquist, 1970). Increased aggression has also been reported following lesions of dorsolateral prefrontal cortex in monkeys (Miller, 1976).…”

“…As in human studies, the prefrontal cortex seems to be important in regulating social cognition in nonhuman primates, with prefrontal cortex lesions resulting in abnormal social behavior-for example, monkeys with prefrontal cortex lesions are described as withdrawn and less explorative (Deets et al, 1970;Peters & Ploog, 1976) and socially isolated after reintegration to the colony (Myers, Swett, & Miller, 1973). One study explored the effects of lesions to the prefrontal cortex and anterior temporal cortex on the social behavior of free-ranging monkeys (Franzen & Myers, 1973).…”

The Size of the Neocortex in Relation to Ecology and Social Structure in Monkeys and Apes

“…Values of an index of social complexity are much higher for polygynous species than for monogynous species of an thropoids [46], Furthermore, in polygynous anthropoid species, such as macaques and cercopithecines, there are neocortical areas such as prefrontal and temporal cortical areas that are involved in a variety of social interac tions. Examples are the maintenance of social bonds, affiliative behaviours, and recognition of vocalization and faces [17][18][19][20][21][22][47][48][49][50], A neuro-anatomical study has demonstrated that some neocortical areas of Saguinus (mo nogynous) are less differentiated than those of Cebidac (such as Saimiri and Cebus) or Cercopithecoidea (such as Macaco) [51]. More over, RSNs were positively and significantly correlated with troop size across anthropoids.…”

“…More recently, Armstrong et al [16] demonstrated that the size of a tha lamic nucleus relative to brain size was re lated to social structure in anthropoids. The neocortex of anthropoids contains areas, such as prefrontal and temporal cortices, which are closely associated with social interactions [17][18][19][20][21][22]. It is hence possible that social struc tures are specifically related to the degree of neocortical development, but there have been few systematic studies that examine relation ships between neocortical size and social structure.…”