Investigation of functional connectivity differences based on anxiety tendencies

Abstract

Introduction: Anxiety is an emotion necessary for human survival. However, persistent and excessive anxiety can be clinically challenging. Increased anxiety affects daily life and requires early detection and intervention. Therefore, a better understanding of the neural basis of mild anxiety is needed. However, previous studies have focused primarily on resting-state functional magnetic resonance imaging (rs-fMRI) in patients with psychiatric disorders presenting with anxiety. Notably, only a few studies have been conducted on healthy participants, and the relationship between anxiety and functional brain connectivity in the healthy range remains unclear. Therefore, in this study, we aimed to clarify the differences in functional brain connectivity at different degrees of anxiety among healthy participants.

Methods: This study included 48 healthy participants with no history of psychiatric disorders. Participants were administered The General Health Questionnaire (GHQ) 60, a psychological test for assessing anxiety, and the Manifest Anxiety Scale (MAS). The participants then underwent rs-fMRI. Based on the results of each psychological test, the participants were classified into normal and anxiety groups, and the functional connectivity between the two groups was compared using a seed-to-voxel analysis.

Results: Comparison of functional brain connectivity between the normal and anxiety groups classified based on the GHQ60 and MAS revealed differences between brain regions comprising the salience network (SN) in both psychological tests. For the GHQ60, the anxiety group showed reduced connectivity between the right supramarginal gyrus and insular cortex compared with the normal group. However, for the MAS, the anxiety group showed reduced connectivity between the right supramarginal and anterior cingulate cortical gyri compared with the normal group.

Conclusion: Functional connectivity within the SN was reduced in the group with higher anxiety when functional brain connectivity at different anxiety levels was examined in healthy participants. This suggests that anxiety is involved in changes in the functional brain connectivity associated with emotional processing and cognitive control.

Keywords: anterior cingulate cortex; anterior insula; anxiety; functional connectivity; resting-state functional MRI; salience network.

Figure 1

Brain regions that showed differences in functional connectivity between the normal and anxiety groups. This indicates the brain regions where a significant difference in functional connectivity strength was observed between the normal and anxiety groups when the right supramarginal gyrus was used as the seed region. Cold clusters indicate lower functional connectivity in the anxiety group than in the normal group. (A) Functional connectivity between the right supramarginal gyrus and the right insular cortex was reduced when the GHQ60 was used. (B) Functional connectivity between the right supramarginal gyrus and the anterior cingulate cortex was reduced when MAS was used. Abbreviation: ACC, anterior cingulate cortex; GHQ60, General Health Questionnaire 60; MAS, Manifest Anxiety Scale.

Figure 2

Relationship between each psychometric test psychological test score and functional connectivity. This represents correlations between Z-scores and psychological test scores between brain regions with significantly different functional connectivity strengths between the normal and anxiety groups. (A) There was no significant correlation between the strength of functional connectivity of the right supramarginal gyrus and right insular cortex and the GHQ60 scores (r = −0.232, p = 0.112). (B) There was a significant negative correlation between the strength of functional connectivity of the right superior marginal gyrus and anterior cingulate cortex and MAS scores (r = −0.424, p = 0.003).