Summary: Francis et al. (2002)

It has long been known that maternal care variations in adult rats are associated with changes in neurochemistry and behaviour. When rats receive higher levels of maternal care behaviour as pups, they are less fearful as adults and tend to show higher levels of maternal behaviour themselves. It has been suggested that both oxytocin and vasopressin are important in the expression of anxiety and social behaviour. Francis et al. (2002) assessed whether the variations observed in maternal care behaviour were associated with differences in both oxytocin and vasopressin receptors in adult offspring brains. Oxytocin binding was increased in adult females (in both the central nucleus of the amygdala and the bed nucleus of the stria terminalis) that received higher levels of maternal care as pups. The same response was not observed in adult males. Francis et al. (2002) did, however, find that amygdala vasopressin increased in adult males that received higher levels of maternal care as pups and, again, this response was sex-specific. They suggest that maternal care influences the expression of oxytocin and vasopressin receptors in a sex-specific manner.