Changes in white matter functional networks across late adulthood.

Area of Science:

• Neuroscience
• Neuroimaging
• Aging Research

Background:

• The aging brain exhibits reduced neuronal density and white matter (WM) integrity, impacting inter-regional communication.
• Blood oxygenation level dependent (BOLD) signals in WM are increasingly recognized as indicators of functional brain organization.
• Previous research has not systematically investigated age-related changes in WM BOLD signals.

Purpose of the Study:

• To comprehensively quantify WM BOLD signals across different scales to assess their potential as functional aging markers.
• To investigate how resting-state WM BOLD signals and their functional connectivities change with normal aging.

Main Methods:

• Spatial independent component analysis (ICA) was used to identify functional units within WM from resting-state BOLD data.
• Functional connectivities (FCs) within and between WM units were measured.
• Graph theory metrics were calculated to model WM as a complex network and assess aging effects on network properties.

Main Results:

• Aging significantly altered spectral powers of BOLD signals in over half of the analyzed WM units.
• A significant decrease in functional connectivities (FCs) within and among WM units was observed with aging.
• Widespread reductions in graph-theoretical metrics indicated diminished information exchange capacity between remote WM regions.

Conclusions:

• WM BOLD signals and their regional interactions demonstrate potential as reliable imaging biomarkers for assessing brain aging.
• These findings highlight the utility of WM BOLD signal analysis for understanding age-related functional changes in the brain.