Linking personality and brain anatomy: a structural MRI approach to Reinforcement Sensitivity Theory

Abstract

Reinforcement Sensitivity Theory (RST) proposes a widely used taxonomy of human personality linked to individual differences at both behavioral and neuropsychological levels that describe a predisposition to psychopathology. However, the body of RST research was based on animal findings, and little is known about their anatomical correspondence in humans. Here we set out to investigate MRI structural correlates (i.e. voxel-based morphometry) of the main personality dimensions proposed by the RST in a group of 400 healthy young adults who completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). Sensitivity to punishment scores correlated positively with the gray matter volume in the amygdala, whereas sensitivity to reward scores correlated negatively with the volume in the left lateral and medial prefrontal cortex. Moreover, a negative relationship was found between the striatal volume and the reward sensitivity trait, but only for male participants. The present results support the neuropsychological basis of the RST by linking punishment and reward sensitivity to anatomical differences in limbic and frontostriatal regions, respectively. These results are interpreted based on previous literature related to externalizing and internalizing disorders, and they highlight the possible role of SPSRQ as a measure of proneness to these disorders.

Keywords: frontostriatal circuit; limbic system; personality; psychopathological predisposition; voxel-based morphometry.

Fig. 1

ROIs included in the SR and SP analyses. The anterior hippocampus corresponds to a previous manual segmentation. Red: amygdala; green: anterior hippocampus; blue: caudate; violet: nucleus accumbens.

Fig. 2

A) Correlation between SR scores and GM volume in the left lateral and medial prefrontal clusters derived from the voxel-wise multiple regression analysis in the whole sample (controlling for age, sex and years of education). B) Partial correlations for males and females showing a GM reduction in the left NAcc in males with high SR in comparison with females (after regressing out age and years of education). C) Partial correlation of the left amygdala GM volume with SP scores in the whole sample (after regressing out age, sex and years of education). NAcc, nucleus accumbens; PFC, prefrontal cortex.

Fig. 3

Negative correlation between scores on the SR scale and GM volume in the left lateral and medial prefrontal cortex and superior temporal regions (P < 0.05 FWE corrected, two-tailed). Bar color represents t-values. L, left; R, right.