Distinct Genetic Influences on Cortical and Subcortical Brain Structures

Area of Science:

• Neuroscience
• Behavioral Genetics
• Human Genetics

Background:

• Understanding the genetic basis of brain structure is crucial for neuroscience.
• Twin studies are a powerful tool for estimating heritability.
• Previous research has explored brain structure heritability, but complex patterns require further investigation.

Purpose of the Study:

• To examine the heritability of brain grey matter structures in older adult twins.
• To identify genetic correlations between different brain regions and hemispheres.
• To elucidate the genetic architecture of human brain structures.

Main Methods:

• Utilized a subsample of older adult twins (93 monozygotic and 68 dizygotic pairs) from the Older Australian Twins Study.
• Estimated heritability for subcortical and cortical brain regions.
• Analyzed genetic correlations between homologous structures in different hemispheres and across various brain regions.

Main Results:

• Heritability estimates for subcortical regions ranged from 0.41 (amygdala) to 0.73 (hippocampus).
• Heritability estimates for cortical regions ranged from 0.55 (parietal lobe) to 0.78 (frontal lobe).
• Identified three main genetically correlated clusters: cortical lobes, basal ganglia, and a cluster including amygdala, hippocampus, thalamus, and nucleus accumbens.

Conclusions:

• Human brain possesses a complex, patterned, and clustered genetic architecture.
• Cortical and subcortical structures, particularly the basal ganglia, have divergent genetic determinants.
• Genetic factors influencing homologous brain regions in both hemispheres are largely shared.