Social competence is reduced in socially deprived rhesus monkeys (Macaca mulatta).

Rhesus monkeys deprived for some period from their mother have often served as a model for the effect of adverse rearing conditions on social competence in humans. Social competence is the capacity to react in a species-specific way to social interactions. The current study assesses whether early deprivation from peers also affects the rates of behavior and social competence in rhesus monkeys. This was studied in groups of rhesus monkeys with different rearing conditions: subadult females that were mother-only reared during their first year of life and subsequently housed with peers were compared with subadult females from five naturalistic social groups. Socially deprived monkeys showed higher rates of submission and stereotypic behaviors than socially reared individuals. In addition, they show socially incompetent behavior, since they react with agonistic behavior to nonthreatening social situations. The results suggest that this socially incompetent behavior is rooted in a general feeling of anxiety toward group companions. The authors hypothesize that anxiety negatively affects social information processing, which results in socially incompetent behavior.

Differential effect of corticosterone on spatial learning abilities in apolipoprotein E knockout and C57BL/6J mice.

Previously, we found that repeated exposure to predator stress corrected the deficit in spatial learning of apolipoprotein E-knockout (apoE0/0) mice, but impaired cognitive performance of wild-type mice. Here we show that elevated corticosterone concentrations, accomplished by subcutaneously implanted pellets, results in similar genotype-related effects on water maze learning: while apoE0/0 mice improved their spatial learning abilities, wild-type mice (C57/Bl6J) became impaired. These results suggest that corticosterone mediates the lasting effects of environmental challenges on apoE-genotype related cognitive performance.