Structural brain imaging correlates of general intelligence in UK Biobank

Area of Science:

• Neuroscience
• Cognitive Science
• Genetics

Background:

• Associations between brain structure and intelligence are not well understood due to limited, small-scale studies.
• Previous research has yielded inconsistent findings regarding brain structure-intelligence relationships.

Purpose of the Study:

• To investigate the relationship between brain structure and general intelligence (g) using a large UK Biobank cohort.
• To identify specific brain regions and white matter tracts associated with general intelligence.

Main Methods:

• Utilized brain MRI and cognitive test data from over 18,000 UK Biobank participants (aged 44-81).
• Derived a general intelligence factor (g) from four cognitive tests.
• Analyzed associations between global brain volumes, grey/white matter microstructure, and g, examining age and sex differences.

Main Results:

• A moderate positive correlation (r=0.276) was found between total brain volume and general intelligence (g).
• Brain structure measures explained significantly more g variance in older (13.6%) versus middle-aged (5.4%) participants.
• Specific regions like the insula, frontal, temporal, occipital cortices, and thalamus, along with certain white matter tracts, showed strong associations with g.

Conclusions:

• Brain structure, particularly total brain volume and regional grey/white matter characteristics, is associated with general intelligence.
• These associations are more pronounced in older adults and show stable predictive power across different samples.
• Findings highlight specific neuroanatomical correlates of intelligence, advancing our understanding of its biological underpinnings.