Behavior and brain uptake of fluorodeoxyglucose in mature and aged C57BL/6mice

This paper describes regional brain energy metabolism, sensorimotor, and me mory functions in mature (12 months) and old (24 months) C57BL/6 mice. Male mice were tested across a variety of sensorimotor procedures and in the Mo rris water maze before evaluating brain uptake of fluorodeoxyglucose (FDG) in the resting state. Mature mice outperformed older mice during the diffic ult sensorimotor and memory tasks, but not the easier tasks. This suggested that the greater sensorimotor and memory demands of a task compromised the performance of the older mice. This conclusion was consistent with the rel ative FDG uptake decreases found in regions mediating sensorimotor coordina tion (vestibular, cerebellar, ventral thalamic regions) and some limbic reg ions linked to memory (mammillary body, posterior cingulate, and piriform c ortices). The inferior colliculus and flocculus had the greatest metabolism in mature mice, as shown by resting FDG uptake, and these regions showed t he most marked hypometabolism in the older mice. The data also showed that the neurobehavioral correlative pattern in older mice was modified. In conc lusion, brain regions with higher energy metabolism, and the behaviors to w hich they are related, were affected most greatly by aging in C57BL/6 mice- suggesting that these areas are more metabolically vulnerable to aging effe cts. (C) 2000 Elsevier Science Inc. All rights reserved.