Altered salience network structure-function integration underlies the decline in cognitive flexibility during aging

Area of Science:

• Neuroscience
• Cognitive Aging
• Brain Connectivity

Background:

• Cognitive flexibility is vital for adapting to changing environments and maintaining general cognition during aging.
• This flexibility depends on the brain's ability to integrate functional dynamics with its structural architecture.
• How age-related changes in structure-function integration affect cognitive flexibility decline is not well understood.

Purpose of the Study:

• To investigate longitudinal aging-related changes in multimodal structure-function integration.
• To examine how these changes relate to cognitive flexibility decline in older adults.
• To identify specific brain networks (Executive Control Network, Default Mode Network, Salience Network) involved in these processes.

Main Methods:

• Utilized resting-state fMRI and diffusion MRI data from two independent datasets.
• Employed a graph signal processing framework to decompose fMRI signals based on structural connectomes.
• Quantified structure-function integration as functional signal coupling and decoupling within subnetworks.

Main Results:

• The salience network subnetwork (SN-A) showed decreased coupling and increased decoupling with aging.
• These SN-A changes were associated with a greater decline in cognitive flexibility over time.
• The default mode network subnetwork (DMN-A) exhibited opposite aging trends: increased coupling and decreased decoupling.

Conclusions:

• Revealed network-specific patterns of structure-function integration changes during normal aging.
• Highlighted the importance of preserved structure-function integration within the salience network for maintaining cognitive flexibility in older adults.
• Suggests that altered integration in specific networks contributes to age-related cognitive decline.