Disturbed social relations during childhood (e.g., social neglect) often lead to aggression-related
psychopathologies in adulthood. Social isolation also increased aggressiveness in
laboratory animals. Here the authors show in rats, that social isolation from weaning
not only increases the level of aggressiveness, but results in abnormal attack patterns
and deficits in social communication. In socially deprived rats, the share of attacks
aimed at vulnerable body parts of opponents (head, throat, and belly) dramatically
increased and the attack/threat ratio was shifted toward attacks, suggesting a decrease
in intention signaling. Moreover, a Multiple Regression Analysis showed that the nonassociation
of attacks with offensive threats predicted the occurrence of vulnerable attacks with
81.1% accuracy. The authors suggest that the social deprivation-induced abnormal aggression
models the aggression-related problems resulting from early social neglect in humans,
and studies on its brain mechanisms may increase our understanding of the mechanisms
underlying psychopathologies resulting from early social problems.
