Personality and local brain structure: Their shared genetic basis and reproducibility

Area of Science:

• Neuroscience
• Behavioral Genetics
• Cognitive Science

Background:

• Cortical architecture is highly heritable, with specific genes linked to distinct brain regions.
• Total surface area correlates with cognitive abilities, suggesting brain structure as a link between genes and behavior.
• The genetic basis of local brain structure's association with cognitive and emotional functioning remains unclear.

Purpose of the Study:

• To investigate the genetic correlation between personality traits and local cortical structure.
• To determine if observed associations generalize across independent samples.
• To explore the functional implications of brain regions associated with personality.

Main Methods:

• Utilized a large-scale twin sample (Human Connectome Project) and two independent replication samples (BGSP, ENIGMA).
• Analyzed genetic correlations between personality traits and local cortical structure measures.
• Performed quantitative functional decoding to interpret the role of associated brain regions.

Main Results:

• Found a genetic overlap between personality and local cortical structure in 10 of 18 phenotypic associations, primarily in frontal cortices.
• Replicated the negative association between medial prefrontal cortex surface area and Neuroticism across all three samples.
• Functional decoding indicated the medial prefrontal cortex is involved in emotional and socio-cognitive processes.

Conclusions:

• Associations between local brain structure and personality are partially under genetic control.
• These associations are generally weak, with the frontal surface area-Neuroticism link being the most robust finding.
• The medial prefrontal cortex's surface area may serve as a genetic endophenotype for neuroticism, related to emotional processing.