Behavioral and electrophysiological effects of early repeated maternal separation

Abstract

AbstractMaternal deprivation or “lack of care” has been identified as one possible risk factor in the development of psychopathology. Animal models of maternal deprivation have been developed in order to better understand the mechanisms underlying its possible long‐term physiological and/or behavioral effects. The present study was designed to evaluate the effects of chronic early maternal separation on electrophysiology and behavior in adult male and female rats. Sprague‐Dawley rats were maternally separated 6 h each day from postnatal day 2 (PN2) to PN6 and from PN9 to PN13. Rats were evaluated at 15 to 18 weeks of age. Overall, adult female rats were found to have higher amounts of slow waves, displayed increased locomotor behavior in photocell cages, and exhibited decreased “anxiety” in novel environments. Adult rats who had experienced early maternal separation were found to have increases in slow wave sleep. Early, repeated maternal separation was also found to reduce the amplitude of the NI component of the event related potential. Behaviorally, the maternally separated rats were less “anxious” as revealed by the open field assessment, but not by the elevated plus maze test. This study suggests that early, repeated maternal separation of 6 h/day may produce behavioral and electrophysiological effects that may be long‐lasting, but not necessarily detrimental to sleep or behavioral regulation. Depression 2:43–53 (1994). © 1994 Wiley‐Liss, Inc.