Stability of Default-Mode Network Activity in the Aging Brain
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Activity attributed to the default-mode occurs during the resting state and is thought to represent self-referential and other intrinsic processes. Although activity in default-associated regions changes across the lifespan, little is known about the stability of default-mode activity in the healthy aging brain. We investigated changes in rest-specific activity across an 8 year period in older participants in the Baltimore Longitudinal Study of Aging (BLSA) neuroimaging study. Comparison of resting-state and recognition memory PET regional cerebral blood flow conditions from baseline and 8-year follow-up shows relative stability of rest-specific activity over time in medial frontal/anterior cingulate, hippocampal and posterior cingulate regions commonly associated with the default-mode. In contrast, prefrontal, parahippocampal and occipital cortical regions, which are not typically associated with default-mode activity, show changes over time. Overall, activity in the major components of the default-mode network remains stable in healthy older individuals, a finding which may assist in identifying factors that discriminate between normal and pathological aging.
KeywordsFunctional imaging Brain function Activation Age fMRI Human Default activity
This research was supported in part by the Intramural Research Program of the NIH, National Institute on Aging and by Research and Development Contract N01-AG-3-2124. We are grateful to the BLSA participants and neuroimaging staff for their dedication to these studies and the staff of the Johns Hopkins PET facility for their assistance.
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