PET STUDIES OF CEREBRAL GLUCOSE-METABOLISM IN CONSCIOUS RHESUS MACAQUES

A growing body of evidence suggests that rhesus macaques may be a good model of human brain aging. We used positron emission tomography (PET ) and F-18-fluorodeoxyglucose (FDG) to measure regional cerebral metab olic rates for glucose (rCMRglc) in young and aged rhesus macaques to determine if age-related decreases, such as those reported in humans, also occur in macaques. Whereas the aged animals had lower metabolic r ates in every brain region studied, the largest differences were in le ft temporal cortex. The largest differences were also observed in left temporal cortex when relative rCMRglc values were used. Both rCMRglc and relative rCMRgle were marked by substantial individual variation w ithin the aged group. This variation may parallel the variation observ ed in behavioral studies. Future studies that include both PET and beh avioral measures should help determine if there is a relationship betw een age-related changes in rCMRgle and behavior.