Effects of exercise and enrichment on behaviour in CD-1 mice

A host of scholarly work has characterized the positive effects of exercise and environmental enrichment on behaviour and cognition in animal studies. The purpose of this study was to investigate the uptake and longitudinal impact of exercise and enrichment on the behavioural phenotype of male and female CD-1 mice. CD-1 mice housed in standard (STD) or exercise and enrichment (EE) conditions post-weaning were tested in the 3 chamber sociability test, open field, and elevated plus maze and exercise activity was monitored throughout the enrichment protocol. Male and female EE mice both showed reduced anxiety and activity in the open field and elevated plus maze relative to sex-matched STD mice. EE altered social behaviours in a sex-specific fashion, with only female EE mice showing increased social preference relative to female STD mice and a preference for social novelty only present in male EE mice. This sexual dimorphism was not observed to be a product of exercise uptake, as CD-1 mice of both sexes demonstrated a consistent trend of wheel rotation frequencies. These findings suggest the importance of considering variables such as sex and strain on experimental design variables in future work on environmental enrichment.