LEISURE ACTIVITIES SHAPE FUNCTIONAL BRAIN CONNECTIVITY ACROSS THE ALZHEIMER’S DISEASE CONTINUUM

Leisure activities (LA) are important proxy-measure of cognitive reserve (CR) and can influence brain network organization. This study examined the association between LA and resting-state functional connectivity (FC) across of Alzheimer's Disease (AD). Participants included individuals with AD (n=46), amnestic-Mild Cognitive Impairment (a-MCI; n =81), Subjective Cognitive Decline (SCD; n =79), and Healthy Subjects (HS; n=70). CR was assessed using the GE-I questionnaire, which evaluates cognitive, social, and physical LA throughout life. Resting-state fMRI data were acquired, and FC within three predefined networks associated with cognitive (default mode network), social (executive network), and physical (cerebellar network) functions. These networks were extracted using MELODIC. LA indices were reduced using principal component analysis. Only results surviving at FWE correction (p<0.05 at cluster level) were considered. Distinct patterns of associations emerged across different clinical stages. a-MCI patients showed inverse relationship between cognitive LA during midlife and social LA during youth, older age, and across the lifespan, DMN and executive networks connectivity, consistent with compensatory neural recruitment associated with CR. In contrast, SCD individuals showed direct association between cognitive LA during midlife and older age with the FC within DMN, suggesting preserved network integrity and brain maintenance mechanisms. In HS, physical LA during midlife and across the lifespan were directly associated with FC within the cerebellar network, indicating efficient network recruitment with preserved overall cognitive efficiency. Overall, these findings indicate that recreational activities differentially modulate brain FC at different stages of AD and healthy aging, supporting distinct reserve-related neural mechanisms.