Extraversion and neuroticism related to the resting-state effective connectivity of amygdala

Abstract

The amygdala plays a key role in emotion processing. Its functional connectivity with other brain regions has been extensively demonstrated to be associated with extraversion and neuroticism. However, how the amygdala affects other regions and is affected by others within these connectivity patterns associated with extraversion and neuroticism remains unclear. To address this issue, we investigated the effective connectivity of the amygdala using Granger causality analysis on the resting-state functional magnetic resonance imaging data of 70 participants. Results showed that extraversion was positively correlated with the influence from the right inferior occipital gyrus (IOG) to the left amygdala, and from the bilateral IOG to the right amygdala; such result may represent the neural correlates of social interactions in extraverts. Conversely, neuroticism was associated with an increased influence from right amygdala to right middle frontal gyrus and a decreased influence from right precuneus to right amygdala. This influence might affect the modulations of cognitive regulation function and self-referential processes in neurotic individuals. These findings highlight the importance of the causal influences of amygdala in explaining the individual differences in extraversion and neuroticism, and offer further insights into the specific neural networks underlying personality.

Figure 1. Regions of EC showing correlation with extraversion.

(A) Extraversion was positively associated with the EC from the right IOG to the left AMG, the EC from the left IOG to the right AMG, and the EC from the right IOG to the right AMG. The hot color indicates the EC of the amygdala that show positive associated with extraversion. The color scale represents t values. (B) The scatter plots represent individual mean EC estimates from extraversion after regressing age, gender, FD, and neuroticism scores. The red circles are the outliers detected by bootstrapping the Mahalanobis distance. EC, effective connectivity; AMG, amygdala; IOG, inferior occipital gyrus.

Figure 2. Regions of EC showing correlation with neuroticism.

(A) Positive association between neuroticism and the EC from the right AMG to the right MFG. (B) Negative association between neuroticism and the EC from the right PCu to the right AMG. The hot and cold colors indicate the EC of amygdala that show positive and negative associated with neuroticism, respectively. The color scale represents t values. Right scatter plots represent individual mean EC estimates from neuroticism after regressing age, gender, FD, and extraversion scores. The red circles are the outliers detected by bootstrapping the Mahalanobis distance. EC, effective connectivity; AMG, amygdala; MFG, middle frontal gyrus; PCu, precuneus.