Voluntary exercise does not ameliorate context memory and hyperarousal in a mouse model for post-traumatic stress disorder (PTSD)

Abstract

Objectives. We investigated the effects of voluntary wheel running as model for intervention on the development of contextual fear and hyperarousal in a mouse model of post-traumatic stress disorder (PTSD). Physical exercise in general has been associated with improved hippocampus-dependent memory performance both in animals and humans. However, studies that have tried to link physical exercise and contextual conditioning in an animal model of PTSD, revealed mixed findings. Methods. Here we tested contextual fear conditioning, generalized fear response, acoustic startle response and emotionality in C57BL/6NCrl mice which had free access to a running wheel for 28 days, compared with control animals which did not run and mice which did not receive a shock during the conditioning phase. Results. We found no significant effects of voluntary running on the above-mentioned variables, except for enhanced anxiety levels in the Dark-Light-Box and O-Maze tests of running mice. Conclusions. Our results suggest that running as a model for intervention does not ameliorate contextual aversive learning but has the potency to change emotional behaviours.