Sex differences for object location memory in rats : the contribution of the dentate gyrus

Abstract

Females exhibit superior object location memory (OLM) compared to males, but the reasons for this sex difference remains unknown. This thesis investigates the role of the dentate gyrus (DG) in an OLM task in normal rats (Experiment 1) and after bilateral adrenalectomy (ADX; Experiment 2). ADX is known to reduce volume of the DG and impair spatial learning. There was no sex difference for OLM in Experiment 1 but females exhibited superior OLM in Experiment 2. Experiment 2 found a significantly smaller DG due to ADX but this had no effect on behaviour. The male DG was significantly larger than the female DG in both experiments. Behaviour during the OLM task was not a predictor of DG volume, although a larger than average DG was related to poor OLM memory in females Thus, the DG involvement for OLM appears to differ between the sexes.