Individual differences in neurocognitive aging in outbred male and female long-evans rats

Individual differences in biology as well as experience and exposures throughout life may contribute risk or resilience to neurocognitive decline in aging. To investigate the role of sex as a biological variable in cognitive function due to normal aging, we used substantial cohorts of healthy male and female aged outbred rats maintained under similar conditions throughout life to assess whether both sexes display a similar distribution of individual differences in behavioral performance using a water maze task optimized to assess hippocampal-dependent cognition in aging. We found both aged male and female rats performed poorer than young adults overall, but with no performance differences between sex in either young adults or aged groups in memory probe tests. In addition, aged male and female rats had similar distributions of individual differences such that the same proportion of male and female performed on par with (intact memory) or outside of (impaired memory) the benchmark of young rats of their respective sex. The data support the use of this outbred model with biological diversity to study the neurobiology of aging trajectories for variation in cognitive outcomes in both male and females. (PsycInfo Database Record (c) 2022 APA, all rights reserved).