White matter integrity and five-factor personality measures in healthy adults

Abstract

The five-factor model organizes personality traits into five factors: Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness. Measures of these personality traits predict people's behaviors and important outcomes of their lives. Therefore, understanding the neural correlates of these personality traits is important. This study assessed the relationships between white matter (WM) integrity and personality traits among 51 healthy participants using diffusion tensor imaging (DTI) and the revised NEO Personality Inventory (NEO-PI-R). Neuroticism correlated positively while Openness and Agreeableness correlated negatively with DTI mean diffusivity (MD) in the corona radiata and superior longitudinal fasciculus, tracts that interconnect prefrontal cortex (PFC), parietal cortex, and subcortical structures. Furthermore, Neuroticism correlated positively with MD in the anterior cingulum and uncinate fasciculus, tracts interconnecting PFC and amygdala. Openness correlated negatively with MD of WM adjacent to the dorsolateral PFC in both hemispheres. These findings suggest that greater Neuroticism associates with worse integrity of WM interconnecting extensive cortical and subcortical structures including the PFC and amygdala and that greater Openness associates with better integrity of WM interconnecting extensive cortical and subcortical structures including the dorsolateral PFC.

Figure 1

Correlations between scores on Neuroticism and values of MD. Red-Yellow color on Montreal Neurological Institute (MNI) T1 template indicates brain regions exhibiting significant correlations between scores on Neuroticism and values of MD. In this figure and all other figures in this paper, green color shows “group mean_FA_skeleton”, and the number below each brain image indicates Z coordinate in MNI space, and only clusters surviving correction for multiple comparisons of voxel-wise whole brain analysis are shown on brain images. Scatter-plots demonstrate correlations between mean MD values (y-axis) and scores on Neuroticism. Mean MD values in this figure and all other figures in this paper were calculated from all voxels from all significant clusters of each participant. Abbreviation: L: left.

Figure 2

Correlations between scores on Openness and MD values. Red-Yellow color on Montreal Neurological Institute (MNI) T1 template indicates brain regions exhibiting significant correlations between scores on Openness and MD values. Scatter-plots demonstrate correlations between mean MD values (y-axis) and scores on Openness. Abbreviation: L: left.

Figure 3

Correlations between scores on Agreeableness and values of MD. Red-Yellow color on Montreal Neurological Institute (MNI) T1 template indicates brain regions exhibiting significant correlations between scores on Agreeableness and values of MD. Scatter-plots demonstrate correlations between mean MD values (y-axis) and scores on Agreeableness. Abbreviation: L: left.