Diffusion MRI of gray matter microstructural profiles in healthy aging

Area of Science:

• Neuroimaging
• Neuroscience
• Gerontology

Background:

• Diffusion-weighted imaging (DWI) is a non-invasive MRI technique providing insights into brain microstructure.
• Historically focused on white matter, DWI is increasingly applied to study gray matter alterations, particularly in healthy aging.

Purpose of the Study:

• To review diffusion MRI studies examining age-related gray matter microstructural differences.
• To explore the implications of these changes for cognitive function in healthy older adults.

Main Methods:

• Narrative review of existing diffusion MRI literature.
• Analysis of studies investigating age-related microstructural changes in cortical, hippocampal, and subcortical gray matter.

Main Results:

• Widespread age-related microstructural differences observed in cortical (frontoparietal), hippocampal, and subcortical regions.
• These changes are behaviorally relevant, particularly for learning and memory domains.
• Gray matter microstructure is influenced by dementia pathology, physical activity, and sleep health.

Conclusions:

• Diffusion MRI is valuable for understanding age-related gray matter changes and cognitive function.
• Future research should incorporate longitudinal designs, multimodal diffusion MRI techniques, and investigate factors like sex, environment, and diet.
• More specific cognitive correlates, such as processing speed, should be defined in future studies.