The amygdala and development of social cognition: theoretical comment on Bauman, Toscano, Mason, Lavenex, and Amaral (2006).

Nonhuman primate studies, using selective amygdala lesions that spare cortical areas and fibers of passage, have helped to clarify the amygdala's specific contribution to social and emotional behavior. M. D. Bauman, J. E. Toscano, W. A. Mason, P. Lavenex, and D. G. Amaral (2006) reported that macaque monkeys (Macaca mulatta) with neonatal neurotoxic amygdala lesions displayed lower rank in social dominance status, reduced aggressive gestures, and enhanced fearful reactions to social cues compared with normal controls and those with neonatal hippocampal lesions when tested as juveniles in a group of peers. These results are discussed in light of a recent study (C. J. Machado & J. Bachevalier, 2006) showing that the same selective amygdala damage in adolescent monkeys did not alter presurgical social dominance status. This variability in behavioral changes after selective amygdala lesions underscores the significant interplay between timing of the lesion, genetic traits, and environmental factors and suggests that the amygdala is not the generator of specific emotional responses, but acts as a modulator to ensure that emotional responses are appropriate to the external stimuli and social context.