Brief and long periods of maternal separation affect maternal behavior and offspring behavioral development in C57BL/6 mice

Abstract

For rats, maternal mediation of brief and longer term dam-pup separations were thought to account for pup differences in adult "emotionality." In this study, early handling (EH), maternal separation (MS), and maternal peer separation (MPS) groups were compared to an animal facility reared (AFR) group for maternal behavior and offspring adult open-field behavior in C57BL/6 mice. Although MS and MPS dams displayed higher levels of maternal behavior upon reunion, these group differences did not predict offspring open-field behavior. However, when offspring behavior was analyzed as a function of specific aspects of maternal behavior, irrespective of treatment group, pups that received high levels of quiescent nursing and activity, but not licking, were less "emotional." Individual differences in maternal licking of pups predicted variability of "emotional" behavior for AFR and EH pups. Thus, for this strain of mouse, individual and not treatment differences in maternal care predict offspring "emotional" development.

Keywords: C57BL; HPA axis; anxiety; early deprivation; early handling; maternal behavior; maternal deprivation; maternal separation; open field; social environment.