Race modifies default mode connectivity in Alzheimer's disease.

Area of Science:

• Neuroscience
• Medical Imaging
• Gerontology

Background:

• Older African Americans exhibit a higher Alzheimer's disease (AD) prevalence than Caucasians.
• Cerebrovascular and socioeconomic factors do not fully explain this racial disparity in AD.
• Previous research indicated lower cerebrospinal fluid (CSF) tau levels in African Americans with AD compared to Caucasians, despite similar beta-amyloid levels.

Purpose of the Study:

• To investigate racial differences in early functional magnetic resonance imaging (fMRI) biomarkers of the default mode network (DMN) in Alzheimer's disease.
• To correlate DMN functional connectivity with established AD biomarkers (CSF amyloid, tau) and cognitive performance across racial groups.

Main Methods:

• Analysis of functional connectivity within DMN subsystems using fMRI in older African Americans and Caucasians.
• Correlation of DMN imaging biomarkers with non-imaging AD biomarkers, including CSF amyloid-beta 1-42, total tau, phosphorylated tau, and cognitive test results.

Main Results:

• Race significantly modifies the association between DMN functional connectivity and cognitive performance.
• Racial differences were observed in the relationship between DMN connectivity and AD biomarkers like tau and amyloid levels.
• Specific inter-subsystem connections within the DMN were identified as being influenced by race.

Conclusions:

• These findings suggest that race influences Alzheimer's disease phenotypes beyond cerebral amyloid deposition.
• The study highlights the importance of considering race in understanding AD progression and developing targeted diagnostic and therapeutic strategies.
• Identifying race-specific DMN connectivity patterns offers potential for improved imaging and neuropathological characterization of Alzheimer's disease.