Impact of Amyloid Burden on Regional Functional Synchronization in the Cognitively Normal Older Adults

Previous studies have shown aberrant functional connectivity in preclinical Alzheimer's disease (AD). However, the effects of beta-amyloid (A beta) retention on regional functional synchronization in cognitively normal older adults still remain unclear. The aim of this study was to explore the distinctive association pattern between A beta retention and regional functional synchronization in cognitively normal older adults. Sixty-one older adults with normal cognition underwent functional magnetic resonance imaging and regional functional synchronizations were quantified using regional homogeneity (ReHo). Subjects were dichotomized using F-18-Florbetaben positron emission tomography imaging into subjects with (A beta+; n = 30) and without (A beta-; n = 31) A beta burden. The A beta+ group exhibited significantly higher ReHo in the fusiform gyrus and lower ReHo in the precuneus compared with the A beta-group. We found significant negative correlations between global A beta retention and ReHo in the precuneus and medial prefrontal cortex and positive correlations between global A beta retention and ReHo in the bilateral lingual gyrus, left fusiform gyrus, and right middle temporal gyrus in the A beta+ group. Our findings suggest that regional functional synchronization might have distinctive association patterns with A beta retention in the cognitively normal older adults. These findings can enrich the functional characterization of early stages of disease progression in AD.