Aging is associated with declines in executive function. We examined how executive functional brain systems are influenced by clinically silent Alzheimer’s disease (AD) pathology and cerebral white matter hyperintensities (WMHs). Twenty-nine younger adults and thirty-four cognitively normal older adults completed a working memory paradigm while functional magnetic resonance imaging (fMRI) was performed. Older adults further underwent lumbar cerebrospinal fluid (CSF) draw for assessment of AD pathology and FLAIR imaging for assessment of WMHs. Accurate working memory performance in both age groups was associated with high fronto-visual functional connectivity (fC). However, in older adults, higher expression of fronto-visual fC was linked with lower levels of clinically silent AD pathology. In addition, AD pathology and WMHs were each independently related to increased fMRI response in the left dorsolateral prefrontal cortex, a pattern associated with slower task performance. Our results suggest that clinically silent AD pathology is related to lower expression of a fronto-visual fC pattern supporting executive task performance. Further, our findings suggest that AD pathology and WMHs appear to be linked with ineffective increases in frontal response in CN older adults.
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This study was supported by the National Institute on Aging and National Center for Advancing Translational Sciences of the National Institutes of Health (grant numbers RO1AG033036, P30AG028383, P01AG030128, TL1TR000115). In addition, JQT is supported by P30AG10124 and U01AG24904, and LMS is supported by U01AG24904.
Gold, Brian T.; Brown, Christopher A.; Hakun, Jonathan G.; Shaw, Leslie M.; Trojanowski, John Q.; and Smith, Charles D., "Clinically Silent Alzheimer's and Vascular Pathologies Influence Brain Networks Supporting Executive Function in Healthy Older Adults" (2017). Neuroscience Faculty Publications. 56.