Alterations in Dynamic Functional Connectivity in Individuals With Subjective Cognitive Decline

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Alzheimer's Disease Research

Background:

• Subjective cognitive decline (SCD) represents a preclinical stage of cognitive impairment.
• Understanding brain network alterations in SCD is crucial for early detection and intervention.
• Dynamic functional connectivity (DFC) offers insights into brain network flexibility beyond static measures.

Purpose of the Study:

• To investigate dynamic functional connectivity (DFC) and static graph theory parameters in individuals with SCD.
• To explore the association between DFC, topological properties, and cognitive performance in SCD.
• To identify potential neuroimaging biomarkers for preclinical Alzheimer's disease detection.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was performed on 32 SCD individuals and 33 controls.
• Group independent component analysis (ICA) identified 7 functional networks.
• Sliding window analysis and k-means clustering identified distinct DFC states, temporal properties, and transition counts. Graph theory analysis assessed static network parameters.

Main Results:

• Four distinct DFC states were identified across the cohort.
• SCD individuals exhibited altered DFC, including increased dwell time in a hypoconnected state (state 4) and decreased dwell time in a hyperconnected state (state 2).
• Reduced transitions between specific DFC states were observed in SCD. No significant differences in static graph theory metrics were found. Altered DFC correlated with cognitive performance.

Conclusions:

• Dynamic functional connectivity, not static network topology, is reconfigured in the SCD stage.
• These DFC alterations may underlie early cognitive decline in SCD.
• DFC patterns show promise as sensitive neuroimaging biomarkers for preclinical Alzheimer's disease detection.