A number of studies in non-human primates have suggested that the amygdala is essential for the normal production and interpretation of social signals. Network researchers conducted a study in rhesus monkeys that challenges this long-held belief. Adult monkeys with amygdala lesions appear to demonstrate normal social behavior, while infant monkeys with amygdala lesions in previous studies have demonstrated impairments in social behavior.
However, these abnormalities may not have been attributable to the absence of the amygdala, but may rather have been attributable to abnormal rearing conditions (isolation or peer-rearing) or to additional damage to structures surrounding the amygdala due to less sophisticated lesioning methods than are currently available. This study found that infant rhesus monkeys with very precise lesions of the amygdala who were reared with their mothers did develop species-appropriate social behaviors, indicating that the amygdala is not necessary for normal social development.
However, these animals did produce more …