Surface-based morphometry reveals the neuroanatomical basis of the five-factor model of personality

Abstract

The five-factor model (FFM) is a widely used taxonomy of human personality; yet its neuro anatomical basis remains unclear. This is partly because past associations between gray-matter volume and FFM were driven by different surface-based morphometry (SBM) indices (i.e. cortical thickness, surface area, cortical folding or any combination of them). To overcome this limitation, we used Free-Surfer to study how variability in SBM measures was related to the FFM in n = 507 participants from the Human Connectome Project.Neuroticism was associated with thicker cortex and smaller area and folding in prefrontal-temporal regions. Extraversion was linked to thicker pre-cuneus and smaller superior temporal cortex area. Openness was linked to thinner cortex and greater area and folding in prefrontal-parietal regions. Agreeableness was correlated to thinner prefrontal cortex and smaller fusiform gyrus area. Conscientiousness was associated with thicker cortex and smaller area and folding in prefrontal regions. These findings demonstrate that anatomical variability in prefrontal cortices is linked to individual differences in the socio-cognitive dispositions described by the FFM. Cortical thickness and surface area/folding were inversely related each others as a function of different FFM traits (neuroticism, extraversion and consciousness vs openness), which may reflect brain maturational effects that predispose or protect against psychiatric disorders.

Keywords: big five; cortical folding; cortical thickness; individual differences; surface area.

Fig. 1.

There was a significant positive association between neuroticism and cortical thickness in a series of fronto-parietal regions (regions in red) (A). In contrast, there was a significant negative association between neuroticism and surface area, cortical volume, and local gyrification index in frontal, parietal, temporal and occipital cortices (regions in blue) (B–D). Color bar: −log₁₀ (P value).

Fig. 2.

There was a significant positive association between extraversion and cortical thickness in the precuneus (in red) (A). In contrast, there was a significant negative association between extraversion and surface area and cortical volume in the superior temporal cortex and entorhinal cortex (regions in blue) (B and C). Finally, the local gyrification index in the fusiform gyrus was positively associated with extraversion (in red) (D). Color bar: −log₁₀ (P value).

Fig. 3.

There was a significant negative association between openness and cortical thickness in a series of frontal and posterior regions (in blue) (A). In contrast, there was a significant positive association between openness and the surface area, cortical volume, and local gyrification index in posterior as well as anterior brain regions (regions in red) (B–D). Color bar: −log₁₀ (P value).

Fig. 4.

There was a significant negative association between agreeableness and cortical thickness, surface area, cortical volume, and local gyrification index in a series of frontal and temporal regions (in blue) (A–D). The only region showing a positive association between openness and local gyrification index was the inferior temporal cortex (D). Color bar: −log₁₀ (P value).

Fig. 5.

There was a significant positive association between conscientiousness and cortical thickness in a series of frontal regions (A). There was also a negative correlation between conscientiousness and surface area, cortical volume and local gyrification index in occipital, temporal and frontal cortices (B–D). Color bar: −log₁₀ (P value).