The Disconnected Brain and Executive Function Decline in Aging.
Higher order speeded cognitive abilities depend on efficient coordination of activity across the brain, rendering them vulnerable to age reductions in structural and functional brain connectivity. The concept of "disconnected aging" has been invoked, suggesting that degeneration of connections between distant brain regions cause cognitive reductions. However, it has not been shown that changes in cognitive functions over time can be explained by simultaneous changes in brain connectivity. We followed 119 young and middle-aged (23-52 years) and older (63-86 years) adults for 3.3 years with repeated assessments of structural and functional brain connectivity and executive functions. We found unique age-related longitudinal reductions in executive function over and above changes in more basic cognitive processes. Intriguingly, 82.5% of the age-related decline in executive function could be explained by changes in connectivity over time. While both structural and functional connectivity changes were related to longitudinal reductions in executive function, only structural connectivity change could explain the age-specific decline. This suggests that the major part of the age-related reductions in executive function can be attributed to micro- and macrostructural alterations in brain connectivity. Although correlational in nature, we believe the present results constitute evidence for a "disconnected brain" view on cognitive aging.
['Fjell|Anders M|AM|', 'Sneve|Markus H|MH|', 'Grydeland|Håkon|H|', 'Storsve|Andreas B|AB|', 'Walhovd|Kristine B|KB|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D001921:Brain D001931:Brain Mapping D000066492:Cognitive Aging D056324:Diffusion Tensor Imaging D056344:Executive Function D005260:Female D005500:Follow-Up Studies D006801:Humans D008137:Longitudinal Studies D008279:Magnetic Resonance Imaging D008297:Male D008609:Mental Status Schedule D008875:Middle Aged D009434:Neural Pathways D057190:Stroop Test D055815:Young Adult
executive function aging functional connectivity structural connectivity diffusion tensor imaging