Longitudinal assessment of default-mode brain function in aging.
Age-related changes in the default-mode network (DMN) have been identified in prior cross-sectional functional magnetic resonance imaging studies. Here, we investigated longitudinal change in DMN activity and connectivity. Cognitively intact participants (aged 49-79 years at baseline) were scanned twice, with a 6-year interval, while performing an episodic memory task interleaved with a passive control condition. Longitudinal analyses showed that the DMN (control condition > memory task) could be reliably identified at both baseline and follow-up. Differences in the magnitude of task-induced deactivation in posterior DMN regions were observed between baseline and follow-up indicating reduced deactivation in these regions with increasing age. Although no overall longitudinal changes in within-network connectivity were found across the whole sample, individual differences in memory change correlated with change in connectivity. Thus, our results show stability of whole-brain DMN topology and functional connectivity over time in healthy older adults, whereas within-region DMN analyses show reduced deactivation between baseline and follow-up. The current findings provide novel insights into DMN functioning that may assist in identifying brain changes in patient populations, as well as characterizing factors that distinguish between normal and pathologic aging.
Department of Psychology, Stockholm University, Stockholm, Sweden; Umeå Center for Functional Brain Imaging (UFBI), Umeå, Sweden; Aging Research Center (ARC) at Karolinska Institute and Stockholm University, Stockholm, Sweden. Electronic address: jonas.persson.1@ki.se.
Jonas
J
Persson
Department of Psychology, Stockholm University, Stockholm, Sweden; Umeå Center for Functional Brain Imaging (UFBI), Umeå, Sweden.
Sara
S
Pudas
Department of Psychology, Stockholm University, Stockholm, Sweden; Aging Research Center (ARC) at Karolinska Institute and Stockholm University, Stockholm, Sweden.
Lars-Göran
LG
Nilsson
Umeå Center for Functional Brain Imaging (UFBI), Umeå, Sweden; Department of Integrative Medical Biology (Physiology), Umeå University, Umeå, Sweden; Department of Radiation Sciences (Diagnostic Radiology), Umeå University, Umeå, Sweden.
Lars
L
Nyberg
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001921:Brain / Q000473:pathology* / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008568:Memory; D008875:Middle Aged; D013997:Time Factors
Aging; Connectivity; Default-mode; Longitudinal; Memory; fMRI