Relationship between Basal Forebrain Resting-State Functional Connectivity and Brain Amyloid-β Deposition in Cognitively Intact Older Adults with Subjective Memory Complaints

Purpose: To evaluate the association between the global fibrillary amyloid-beta pathology and the basal forebrain connectivity at rest in cognitively intact older adults at risk for Alzheimer disease. Materials and Methods: This retrospective study was approved by the local ethics committee and written informed consent was obtained from all participants. Resting-state functional connectivity (RSFC) of anterior and posterior basal forebrain seeds was investigated, as well as PET-measured global amyloid-beta load by using standardized uptake value ratio (SUVR) in 267 older cognitively intact individuals with subjective memory complaints (age range, 70-85 years; overall mean age, 75.8 years; 167 women [mean age, 75.9 years] and 100 men [mean age, 75.8 years]). The participants were from the Investigation of Alzheimer's Predictors in Subjective Memory Complainers (INSIGHT-preAD) cohort (date range, 2013-present). The relationship between SUVR and the basal forebrain RSFC was assessed, followed by the effects of apolipoprotein E (APOE) genotype and sex on the basal forebrain RSFC. Results: Higher SUVR values correlated with lower posterior basal forebrain RSFC in the hippocampus and the thalamus (Pearson r = -0.23; P<.001 corrected for familywise error [FWE]). Both sex and APOE genotype impacted the associations between basal forebrain RSFC and the global amyloid deposition (t values >3.59; P<.05 corrected for FWE). Conclusion: Data indicate a distinct in vivo association between posterior basal forebrain dynamics and global fibrillary amyloid-beta pathology in cognitively intact older adults with subjective memory complaints; both apolipoprotein E and sex moderate such association. (c) RSNA, 2018