Age-related differences in test-retest reliability in resting-state brain functional connectivity

Area of Science:

• Neuroscience
• Neuroimaging
• Brain Connectivity

Background:

• Resting-state functional MRI (rs-fMRI) is crucial for studying brain functional connectivity (FC).
• Previous research focused on FC reliability in younger adults, leaving older adults understudied.
• Test-retest reliability of resting-state functional connectivity (RSFC) in older adults remains unexamined.

Purpose of the Study:

• To investigate age-related differences in RSFC reliability and stability.
• To examine the impact of global signal regression (GSR) on RSFC reliability and stability.
• To compare RSFC reliability between younger and older adults.

Main Methods:

• Utilized rs-fMRI data from 29 younger and 26 older adults from the ICBM dataset.
• Defined 92 regions of interest (ROIs) across key brain networks.
• Calculated RSFC using z-transformed correlation coefficients from three scans per subject, with and without GSR.

Main Results:

• Younger adults demonstrated significantly higher RSFC reliability than older adults, both with and without GSR.
• Both age groups exhibited high multi-scan stability of RSFC, with no significant age-related differences.
• GSR reduced overall RSFC reliability but increased stability in both groups, potentially affecting group comparisons.

Conclusions:

• Aging is associated with reduced RSFC reliability, though within-subject stability remains high across scans.
• GSR influences RSFC reliability and stability differently across age groups.
• Findings highlight the importance of considering age and preprocessing methods when interpreting RSFC findings.