Progressive Bidirectional Age-Related Changes in Default Mode Network Effective Connectivity across Six Decades.

Area of Science:

• Neuroscience
• Cognitive Aging
• Brain Imaging

Background:

• The default mode network (DMN) is crucial for resting-state brain function and implicated in cognitive disorders.
• Investigating DMN changes in normal aging is essential due to its role in age-related cognitive decline.

Purpose of the Study:

• To examine age-related alterations in the functional connectivity of the DMN in healthy adults.
• To identify patterns of change in DMN connectivity across the lifespan.

Main Methods:

• Utilized blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) during rest.
• Analyzed data from 120 healthy participants across six decade cohorts (20s to 70s).
• Employed structural equation modeling (SEM) to assess inter-regional connectivity within the DMN.

Main Results:

• Found significant, progressive changes in 8 out of 13 DMN connectivity paths.
• Observed bidirectional changes: four paths increased, and four decreased with age.
• Identified early onset of these changes, often significant by the 30s or 40s.
• Noted paired increases and decreases in connectivity, suggesting compensatory mechanisms.

Conclusions:

• Age-related changes in DMN functional connectivity are bidirectional, progressive, and begin early in adulthood.
• These physiological shifts are integral to the normal aging process.
• The findings provide insights into the neural basis of cognitive aging.