Interrelating differences in structural and functional connectivity in the older adult's brain

Area of Science:

• Neuroscience
• Cognitive Aging
• Brain Connectivity

Background:

• Normal aging restructures the brain's functional connectome, shifting towards greater integration.
• Age-related changes in structural connectivity may underlie functional reorganization and cognitive variability.
• The precise relationship between brain structure, function, and cognition in older adults remains unclear.

Purpose of the Study:

• To identify patterns of functional connectivity (FC) and structural connectivity (SC) associated with aging and cognitive performance in older adults.
• To investigate the interplay between FC, SC, and cognitive variability in aging.
• To characterize distinct aging profiles based on brain network organization.

Main Methods:

• Utilized diffusion-weighted and resting-state functional MRI data from 573 older adults (55-85 years).
• Applied partial least square regression to 400 regional FC and SC estimates across seven resting-state networks.
• Correlated connectivity patterns with cognitive performance data.

Main Results:

• Identified three distinct aging profiles in older adults.
• Observed that functional connectivity patterns varied with the severity of age-related structural connectivity decline.
• Found that a highly interconnected functional system, associated with minor structural connectivity loss, correlated with the most severe cognitive decline, suggesting dedifferentiation.

Conclusions:

• Increased functional network integration in older adults may represent dedifferentiation, particularly when structural connectivity declines.
• Functional integration appears to increase as structural connectivity deteriorates, but this does not necessarily preserve cognitive performance.
• The structure-function relationship in aging highlights neurobiological sources of cognitive variability.