3. Functional connectivity reorganization over age and Alzheimer's disease

COEX 

Cognitive aging is a phenomenon that eventually affects most elderly individuals. This process is accelerated in neurodegenerative diseases like Alzheimer's disease (AD), which involve clinical impairment and decline in functional activities of daily living. Aging is accompanied by changes in brain functional network organization, with one of the hallmarks being decrease in system segregation (1). Similarly, nonlinear alterations to functional networks have been described in AD, posited as early neuronal responses to (and perhaps drivers of) AD pathophysiology (2). Functional changes in aging and AD have, however, mostly been studied in isolation, and the degree to which these phenomena interrelate is not well understood. Further, little is known about how variable such changes are in the population. In this exploratory study, we investigate how the brain's functional networks are reorganized at the individual level in aging and AD independently.