Mapping the modulating effect of transcutaneous auricular vagus nerve stimulation on voxel-based analyses in patients with first-episode major depressive disorder: a resting-state fMRI study.

Abstract

Seed-based analysis find that transcutaneous auricular vagus nerve stimulation (taVNS) can modulate the dysfunctional brain network in patients with major depressive disorder (MDD). The voxel-based neuro-psychological mechanism of taVNS on patients with first-episode MDD is poorly understood. Twenty-two first-episode MDD patients accepted 8-week taVNS treatment. Resting-state fMRI were scanned before and after the treatment. Voxel-based analyses were performed to characterize the spontaneous brain activity. Health controls (n = 23) were recruited to minimize the test-retest effects. The analysis of covariance (ANCOVA) was performed to determine the treatment-related changes. Then the correlations between the changes of the brain activity and the Hamilton Depression Rating Scale (HAMD) / Hamilton Anxiety Scale remission rate were estimated. Significant group-by-time interactions on voxel-based analyses were observed in inferior ventral striatum (VSi) and precuneus. Post-hoc analyses showed that taVNS inhibited the higher brain activity in the VSi, while upregulated the precuneus. The functional connectivity (FC) between VSi and precuneus decreased. Positive correlations were found between the HAMD remission rate and the alterant brain activity in the VSi. TaVNS reduced the functional connectivity between VSi and precuneus by normalizing the abnormal spontaneous brain activity of VSi in first-episode MDD patients.