Investigating the correlation between cortical lateralization and personality traits in young Chinese adults through structural magnetic resonance imaging.

Background: Cortical lateralization is a fundamental aspect of human cognitive brain function, frequently conceptualized as an enduring neurobiological correlate of individual personality. However, a comprehensive and reliable assessment of cortical asymmetry, integrating multiple lateralization indices (LIs), remains elusive, limiting our understanding of the relationship between cortical asymmetry and personality traits. This study employed neuroimaging assessments in order to investigate potential associations between patterns of cortical lateralization and personality traits.

Methods: A well-characterized cohort of 215 healthy right-handed Chinese adults (age range, 20-30 years) participated in comprehensive behavioral assessments and high-resolution structural magnetic resonance imaging (sMRI) acquisition. Cortical LIs were systematically quantified across five morphometric parameters: surface area, cortical thickness, gray matter volume, mean curvature, and folding index. To rigorously investigate associations between structural hemispheric asymmetry and tridimensional personality traits [novelty seeking (NS), harm avoidance (HA), reward dependence (RD)], partial correlation analyses were conducted while controlling for age, sex, and total intracranial volume. This multivariate approach enabled isolation of lateralization effects from potential volumetric confounders, with statistical thresholds corrected for multiple comparisons using the false discovery rate (FDR) method.

Results: NS demonstrated significant positive associations with cortical thickness LIs in the caudal anterior cingulate cortex (r=0.144, P=0.036)​, while exhibiting inverse correlations with gray matter volume LIs in the postcentral cortex (r=-0.136, P=0.048)​. HA manifested distinct neuroanatomical signatures: negative correlations with LIs of mean curvature in the caudal middle frontal cortex (r=-0.174, P=0.011)​, surface area in the precuneus (r=-0.151, P=0.028)​, and the folding index of the inferior parietal cortex (r=-0.143, P=0.037)​. Conversely, positive associations emerged with cortical thickness LIs in the pericalcarine cortex (r=0.136, P=0.048)​. Additionally, RD displayed divergent cortical correlates: positive relationships with the LIs of mean curvature of the inferior temporal cortex (r=0.157, P=0.022)​, and negative associations between the folding index of the medial orbitofrontal cortex and this trait (r=-0.150, P=0.029).

Conclusions: The tridimensional personality traits are underpinned by corresponding anatomical structural bases, which not only demonstrate the close link between brain morphology and behavioral characteristics, but also provide neuroimaging evidence for personality trait theories. This holds significant implications for elucidating the neurobiological mechanisms of individual personality formation and offers a foundation for further research into structural and circuit abnormalities in individuals with personality disorders.