Does macroscale grey matter morphometry have personality
Personality traits are key indices of inter-individual variation in complex behaviors. Large-scale neuroimaging studies have reported inconsistent results on the association between personality and local grey matter structure. In three large-scale datasets of personality and cortical structure in twins and unrelated individuals (N=2824) we replicate both positive and null-results in personality neuroimaging. Positive results were observed between agreeableness, neuroticism, and openness in predominantly frontal regions in the twin-sample, where phenotypical correlations were driven by additive genetic factors. In addition, spatial patterns of genetic correlation between cortical thickness and openness were mirrored by phenotypic patterns in all samples. Last, using a multivariate approach, we identified a robust, heritable, relation between a latent personality component, emphasizing extraversion and openness, and a unique cortical thickness signature stretching from unimodal to heteromodal cortices. While our observations provide evidence of a genetic origin of correlations between grey matter and personality, associations were weak and highlighted robustness of whole-brain spatial patterns in relation to latent personality components, rather than single regions and traits.