text: Prior Parity Positively Regulates Learning and Memory in Young an...: Ingenta Connect
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  Authors: Zimberknopf, Erica1; Xavier, Gilberto F2; Kinsley, Craig H3; Felicio, Luciano F4
  Source: Comparative Medicine, Volume 61, Number 4, August 2011, pp. 366-377(12)
  Reproductive experience in female rats modifies acquired behaviors, induces long-lasting functional neuroadaptations and can also modify spatial learning and memory. The present study supports and expands this knowledge base by employing the Morris water maze, which measures spatial memory. Age-matched young adult (YNG) nulliparous (NULL; nonmated) and primiparous (PRIM; one pregnancy and lactation) female rats were tested 15 d after the litter's weaning. In addition, corresponding middle-aged (AGD) PRIM (mated in young adulthood so that pregnancy, parturition, and lactation occurred at the same age as in YNG PRIM) and NULL female rats were tested at 18 mo of age. Behavioral evaluation included: 1) acquisition of reference memory (platform location was fixed for 14 to 19 d of testing); 2) retrieval of this information associated with extinction of the acquired response (probe test involving removal of the platform 24 h after the last training session); and 3) performance in a working memory version of the task (platform presented in a novel location every day for 13 d, and maintained in a fixed location within each day). YNG PRIM outperformed NULL rats and showed different behavioral strategies. These results may be related to changes in locomotor, mnemonic, and cognitive processes. In addition, YNG PRIM exhibited less anxiety-like behavior. Compared with YNG rats, AGD rats showed less behavioral flexibility but stronger memory consolidation. These data, which were obtained by using a well-documented spatial task, demonstrate long lasting modifications of behavioral strategies in both YNG and AGD rats associated with a single reproductive experience.
  Affiliations: 1: Physiology and Pharmacology Laboratory, School of Veterinary Medicine, Centro Universitário da Fundação de Ensino Octávio Bastos, São João da Boa Vista, Brazil 2: Department of Physiology, Biosciences Institute, University of São Paulo, São Paulo, Brazil 3: Department of Psychology, University of Richmond, Richmond, Virginia, USA 4: Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil