Amygdala-cingulate intrinsic connectivity is associated with degree of social inhibition

Abstract

The tendency to approach or avoid novel people is a fundamental human behavior and is a core dimension of social anxiety. Resting state fMRI was used to test for an association between social inhibition and intrinsic connectivity in 40 young adults ranging from low to high in social inhibition. Higher levels of social inhibition were associated with specific patterns of reduced amygdala-cingulate cortex connectivity. Connectivity was reduced between the superficial amygdala and the rostral cingulate cortex and between the centromedial amygdala and the dorsal anterior cingulate cortex. Social inhibition also modulated connectivity in several well-established intrinsic networks; higher social inhibition correlated with reduced connectivity with default mode and dorsal attention networks and enhanced connectivity in salience and executive control networks. These findings provide important preliminary evidence that social inhibition reflects differences in the underlying intrinsic connectivity of the brain in the absence of social stimuli or stressors.

Keywords: Anxiety; Inhibited temperament; Prefrontal cortex; Resting state; Social anxiety disorder; fMRI.

Fig. 1

Positive intrinsic connectivity is reduced in high social inhibition. Strength of intrinsic connectivity was negatively associated with social inhibition across each of three amygdala subnuclei. Top row: Significant t-maps are shown on standard template brains (FWE corrected p < .05). Middle row: Scatter plots illustrate the association between social inhibition scores and connectivity extracted from the overall significance map. R² values are provided as an effect size. Scatterplots show values for right superficial, left centromedial, and right laterobasal amygdala subnuclei, respectively. Filled circles represent participants with social anxiety disorder. Bottom row: Bar graphs show average positive connectivity by social inhibition tertile, with standard error bars, based on data presented in the scatterplots above.

Fig. 2

Negative intrinsic connectivity is reduced in high social inhibition. Strength of intrinsic connectivity was negatively associated with social inhibition across each of three amygdala subnuclei. Top row: Significant t-maps are shown on standard template brains (FWE corrected p < .05). Middle row: Scatter plots illustrate the association between social inhibition scores and connectivity extracted from the overall significance map. R² values are provided as an effect size. Scatterplots show values for left superficial, left centromedial, and left laterobasal amygdala subnuclei, respectively. Filled circles represent participants with social anxiety disorder. Bottom row: Bar graphs show average negative connectivity by social inhibition tertile, with standard error bars, based on data presented in the scatterplots above.

Fig. 3

Social inhibition is correlated with intrinsic connectivity in four well-established networks. Significant t-maps maps are shown on standard template brains (FWE corrected p < .05). Scatter plots illustrate the association between social inhibition scores and connectivity in each significant cluster. R² values are provided as an effect size. Filled circles represent participants with social anxiety disorder. Bar graphs show average positive connectivity by social inhibition tertile, with standard error bars, for each significant cluster.