Brain aging differs with cognitive ability regardless of education.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Higher general cognitive ability (GCA) correlates with reduced neurodegenerative disease risk.
• The underlying neural mechanisms linking GCA to brain structure across the lifespan remain unclear.
• GCA may confer protection through brain reserve (larger cortical tissue) or brain maintenance (less atrophy).

Purpose of the Study:

• To investigate the association of GCA with brain reserve and brain maintenance mechanisms.
• To examine how GCA relates to cortical volume, area, and thickness throughout adulthood.
• To differentiate between GCA's role in maintaining cortical volume versus preventing atrophy.

Main Methods:

• Utilized longitudinal neuroimaging data from 3327 healthy adults (7002 MRI scans, ages 20-88).
• Analyzed GCA's association with cortical volume, area, and thickness over an 11-year follow-up.
• Controlled for education and polygenic scores for GCA and education.

Main Results:

• Found widespread positive associations between GCA and cortical characteristics (level-level effects).
• Identified specific brain regions where higher GCA was linked to reduced cortical atrophy over time (level-change effects).
• These associations persisted even after accounting for genetic predispositions for GCA and education.

Conclusions:

• Higher GCA is associated with greater cortical volume through both brain reserve and brain maintenance.
• These mechanisms contribute to preserving brain structure across the adult lifespan.
• Findings elucidate neural pathways linking cognitive ability to brain health and resilience.