Biomarkers

Area of Science:

• Neuroscience
• Medical Imaging
• Alzheimer's Disease Research

Background:

• Subjective cognitive decline (SCD) represents a high-risk group for preclinical Alzheimer's disease (AD).
• Neurovascular coupling (NVC), the relationship between neuronal activity and cerebral blood flow (CBF), offers insights into neurodegenerative diseases.
• Spatial navigation impairment is an early indicator in SCD, but its link to NVC changes assessed by ultra-high field MRI remains unclear.

Purpose of the Study:

• To investigate alterations in NVC and their association with spatial navigation function in individuals with SCD.
• To utilize advanced 5.0T MRI techniques, including arterial spin labeling (ASL) and multi-echo functional MRI (fMRI), for high-resolution imaging.

Main Methods:

• Recruited 30 normal controls (NC) and 29 SCD individuals for comprehensive assessments.
• Measured CBF using ASL and analyzed brain activity using fMRI (ALFF, fALFF).
• Compared NVC (CBF/ALFF, CBF/fALFF ratios) between groups and correlated findings with spatial navigation, cognitive performance, and plasma biomarkers.

Main Results:

• SCD individuals exhibited reduced NVC and poorer spatial navigation performance.
• Significantly lower CBF and CBF/ALFF, CBF/fALFF ratios were observed in specific brain regions in the SCD group.
• NVC ratios, plasma biomarkers, and spatial navigation performance showed significant correlations, with combined imaging and navigation data achieving high classification accuracy for SCD.

Conclusions:

• The SCD population demonstrates impaired NVC and spatial navigation deficits, significantly associated with each other.
• Brain NVC decoupling is proposed as a potential neuropathological mechanism underlying spatial navigation impairment in SCD.