Resting-state functional connectivity abnormalities in subjective cognitive decline: A 7T MRI study.

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Geriatric Medicine

Background:

• Resting-state functional connectivity (FC) MRI detects early Alzheimer's disease (AD) changes.
• Studies on FC in subjective cognitive decline (SCD) yield conflicting results.
• No 7 Tesla (7T) MRI studies have investigated FC in SCD.

Purpose of the Study:

• To investigate functional connectivity (FC) alterations in individuals with SCD using 7T fMRI.
• To assess the association between FC in canonical brain networks and cognitive/clinical features in SCD.

Main Methods:

• Sixty-six participants (24 controls, 14 SCD, 28 cognitively impaired [CI]) were recruited.
• Participants underwent 7T fMRI to evaluate FC in default mode network (DMN) and ventral attention network (VAN).
• Cognitive assessments, clinical evaluations, and AD biomarker analysis were performed.

Main Results:

• SCD participants exhibited normal cognition and AD biomarkers, with a trend for higher depressive symptoms.
• Compared to controls and CI groups, SCD individuals showed increased FC in frontal DMN and VAN nodes.
• Elevated FC in DMN and VAN correlated with poorer cognitive performance, independent of depressive symptoms.

Conclusions:

• Hyper-connectivity in the DMN and VAN may represent a signature of age-related cognitive decline in SCD.
• These findings suggest potential utility of 7T fMRI for characterizing early cognitive changes in at-risk individuals.
• SCD individuals with higher FC may have a lower risk of progressing to Alzheimer's disease.