Alterations in functional connectivity in individuals with subjective cognitive decline and hippocampal atrophy

Abstract

Objectives The aim of this study was to determine whether individuals with Subjective Cognitive Decline (SCD), particularly those with a neurostructural marker of risk for AD (SCD+), exhibit differences in the functional connectivity of the Default-Mode Network (DMN) relative to controls, as this network is known to be altered in the AD continuum. Design Cross-sectional study. Setting Galicia, Northwest Spain. Participants The sample compromised 133 participants: 69 controls, 51 SCD and 13 SCD+. Measurements Seed-to-voxel analysis was conducted using four DMN ROIs. Dynamic independent component analysis of the DMN was also performed. Results The SCD and SCD+ groups exhibited DMN hyperconnectivity, which was more extensive in the SCD+ group. Increased anti-correlations between DMN and task-positive parietal regions were related to poorer executive scores in SCD+ and a tendency for higher DMN recurrence in SCD+. Conclusions Hippocampal atrophy as a SCD+ biomarker is associated with extensive DMN hyperconnectivity and increased anti-correlations between DMN and task-positive network regions.