High-resolution structural connectivity mediates age-related differences in functional connectivity and fluid...

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Human Lifespan Studies

Background:

• Age-related cognitive decline is linked to white matter degradation.
• Higher resolution diffusion-weighted imaging may offer more precise white matter connectivity estimates than standard resolution.

Purpose of the Study:

• Compare age-related white matter structural connectivity differences using standard vs. high-resolution diffusion-weighted imaging.
• Assess the ability of these measures to explain age-related functional connectivity and cognitive changes.

Main Methods:

• Cross-sectional study of 140 healthy adults (ages 18-88).
• Acquired standard and high-resolution diffusion-weighted imaging and resting-state functional MRI.
• Assessed cognition (memory, executive function, perceptual-motor speed) and connectivity using graph theory.

Main Results:

• High-resolution imaging showed greater age-related decreases in sensorimotor, ventral attention, and sub-cortical networks.
• Age-related functional connectivity decline was mediated by high-resolution structural connectivity in the default mode network.
• High-resolution imaging uniquely mediated age-related fluid cognition decline via within-network connectivity.

Conclusions:

• High-resolution diffusion-weighted imaging better captures age-related white matter changes.
• These changes constrain age-related alterations in brain function and cognitive performance.
• Findings highlight the importance of imaging resolution for studying cognitive aging.