Gonadal hormones and voluntary exercise interact to improve discrimination ability in a set-shift task.

Exercise has been demonstrated to improve multiple facets of health, including cognitive function. Rodent studies have suggested that exercise has robust effects on the hippocampus and on tasks that require the hippocampus. However, studies of the effects of exercise in humans often focus on the benefits to cognitive processes that engage areas outside of the hippocampus, such as executive function. Additionally, when exercise's cognitive benefits are examined, consideration of both males and females, and gonadal hormones, is rarely made. Here we looked at the interaction of gonadal hormones and exercise in terms of the ability of male and female rats to learn to discriminate rewarded from unrewarded arms in a T maze based on either brightness (white vs. black) or texture (rough vs. smooth) and then to set-shift (a measure of executive function), where this required discrimination is based on the opposite dimension. Gonadectomized or intact males and females had access to running wheels for 2 weeks before being tested. Intact males and females given access to unlocked running wheels performed better at the initial discrimination (Set 1) compared with intact males and females with locked running wheels but not at the set shift (Set 2). No advantage of exercise was observed in gonadectomized rats.