The Maternal Separation Paradigm and Adult Emotionality and Cognition in Male and Female Wistar Rats

• Published in: Pharmacology, biochemistry and behavior Vol. 64; no. 4; pp. 705 - 715
• Main Authors: Lehmann, J, Pryce, C.R, Bettschen, D, Feldon, J
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.1999
• Subjects: Active avoidance; Analysis of Variance; Animals; Avoidance Learning; Cognition - physiology; Conditioned freezing; Conditioning (Psychology); Elevated plus-maze; Emotions - physiology; Female; Male; Maternal Deprivation; Maternal separation; Maze Learning; Motor Activity; Open field; Rat; Rats; Rats, Wistar; Sex Characteristics; Sex differences; Water maze; Weaning; Conditioned freezing; Maternal separation; Rat; Water maze; Sex differences; Active avoidance; Open field; Elevated plus-maze
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/S0091-3057(99)00150-1

A single 24-h maternal separation (MS) in the rat during the stress hyporesponsive period alters adult behavior and neuroendocrine stress response. The age of the animal at MS might be a crucial factor for effects in adulthood. We report here on adult behavioral effects of MS performed on postnatal day 4 (MS4), 9 (MS9), or 18 (MS18) in male and female Wistar rats. Unrelated subjects were used to avoid confounding litter effects. Subjects were tested on paradigms of unconditioned fear/anxiety, i.e., open field and elevated plus-maze, and on paradigms involving learning in an aversive situation, i.e., conditioned freezing, active avoidance, and water maze. In line with our predictions we obtained (a) sex differences that were consistent with enhanced fear/anxiety in males relative to females, (b) evidence that MS4 yielded deficits in active avoidance learning and conditioned freezing (trend level), whereas MS9 yielded enhanced active avoidance and water maze learning, (c) evidence (at trend level) that these effects of MS are greater in males than in females. There was no evidence for an effect of MS on paradigms of unconditioned fear/anxiety. We conclude that MS, irrespective of the age at separation, does not provide a robust environmental model of modified behavior in aversive situations.