Age-related cognitive decline in rats is sex and context dependent

Previously, we had observed age-related cognitive decline in male rats compared to adolescent and adult rats. This was shown in both a multi-branched maze test (MBM), as well as in the Morris water maze test (MWM). In the present study, we compared the behavior of similar age groups in both male and female rats using the same paradigms. The results confirmed the increase in errors and time spent in MBM in aged male rats compared to other age groups. However, no such differences were observed in female rats. In the acquisition phase of MWM, aged male rats did not differ significantly from the other two groups in terms of time spent in quadrants, whereas aged female rats spent significantly more time in quadrants compared to the other 2 age groups. Aged male rats also travelled significantly more than the other 2 age groups during the acquisition phase, whereas no such differences were observed in female rats. In both short term (30 min post acquisition) and long term (24 h after acquisition) retrieval phases of MWM, significant gender-related differences were also observed in all age groups. These findings suggest gender- and context-dependent alterations in cognitive functions during aging.