Abstract
Brain age gap refers to the difference between chronological and brain age based on computational models derived from various neuroimaging phenotypes. Studies in humans have reported that brain age gap is a biological measure that is sensitive to the effects of genetic, environmental and health-related variables on the pace of aging. Here, for the first time, we tested whether estimates of brain age gap could be derived from neuroimaging data obtained in chimpanzees and whether they were associated with different cognitive and motor phenotypes. Archived measures of cortical thickness and surface area were obtained from 34 brain regions in a sample of 215 chimpanzees from the National Chimpanzee Brain Resource. Brain age gap values were computed and tested for their association with individual variation in cognition and motor function. The mean absolute average age gap was ~ 6 years in chimpanzees, a value that overlaps with reports in human subjects. Chimpanzees with "older" brain ages performed more poorly on a measure of cognition compared to individuals with "younger" brains, after controlling for the sex and rearing effects. Like in humans, brain age gap can be used as a valid biomarker of brain aging in chimpanzees and is sensitive to individual differences in cognition.