Structural and Functional Hippocampal Changes in Subjective Cognitive Decline From the Community.

Area of Science:

• Neuroimaging
• Alzheimer's Disease Research
• Cognitive Neurology

Background:

• Subjective Cognitive Decline (SCD) represents an early risk state for Alzheimer's Disease (AD).
• Community-recruited individuals with SCD may be more vulnerable than clinic-based patients.
• Investigating early brain changes in SCD is crucial for disease intervention.

Purpose of the Study:

• To examine structural and functional connectivity alterations in the hippocampus of community-recruited individuals with SCD.
• Utilize structural and resting-state functional MRI (fMRI) for comprehensive brain analysis.

Main Methods:

• Recruited 35 individuals with SCD and 32 healthy controls.
• Acquired resting-state fMRI and high-resolution T1-weighted MRI data.
• Employed voxel-based morphometry for structural analysis and seed-based analysis (hippocampal tail and whole hippocampus) for functional connectivity.

Main Results:

• SCD individuals exhibited reduced gray matter volume in bilateral hippocampal tails and enlarged bilateral paracentral lobules.
• Decreased resting-state functional connectivity (rsFC) was observed between the hippocampal tail and the right medial prefrontal cortex (mPFC) and left temporoparietal junction (TPJ).
• Whole hippocampus rsFC was reduced with bilateral mPFC and TPJ; these changes correlated with Montreal Cognitive Assessment (MoCA) scores.

Conclusions:

• Community-sourced SCD is associated with significant hippocampal structural and functional changes.
• These observed hippocampal alterations may function as potential biomarkers for SCD.
• Findings highlight the hippocampus's role in the earliest stages of cognitive decline.