Possible mechanisms of auricular acupoint stimulation in the treatment of migraine by activating auricular vagus nerve. / 从耳迷走神经探讨耳穴治疗偏头痛的可能机制.

Under the guidance of traditional Chinese medicine theory, the clinical research of auricular acupoint stimulation in the treatment of migraine has gained a lot, and the curative efficacy is definite, but its mechanism remains unclear. In the present paper, we discussed the efficacy of auricular acupoint stimulation including "transcutaneous auricular vagus nerve stimulation" (taVNS) in the treatment of migraine in recent years. Through bibliometric analysis, we screened out top 10 auricular acupoints (Shenmenï¼»TF4ï¼½, Pizhixiaï¼»AT4ï¼½, Jiaoganï¼»AH6aï¼½, Ganï¼»CO12ï¼½, Yidanï¼»CO11ï¼½, Neifenmiï¼»CO18ï¼½, Shenï¼»CO10ï¼½, Nieï¼»AT2ï¼½, Zhenï¼»AT3ï¼½ and Eï¼»AT1ï¼½) which were the most frequently used for migraine. Majority of these auricular acupoints just distributed in the region innervated by auricular vagus nerve. Thus, we thought that the analgesic effect of needling these auricular acupoints for migraine was produced by triggering the auricular vagus nerve, and concluded that the central mechanism underlying induction of analgesic effect by activating auricular vagus nerve may be achieved by activating the descending pain regulation pathway of the locus coeruleus nucleus and dorsal raphe nucleus. In addition, taVNS-induced 1) regulation of the activities of brain's default network and pain matrix, 2) activation of the cortical descending pain regulation pathway, and 3) inhibition of the neuroinflammatory response may also contribute to its ameliorating effect of migraine. This paper may provide ideas for the future research on the mechanism of auricular acupoint treatment of migraine.

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 functional magnetic resonance imaging study

Introduction: Seed-based analysis has shown that transcutaneous auricular vagus nerve stimulation (taVNS) can modulate the dysfunctional brain network in patients with major depressive disorder (MDD). However, the voxel-based neuropsychological mechanism of taVNS on patients with first-episode MDD is poorly understood. The objective of this study was to assess the effects of an 8-week course of taVNS on patients with first-episode MDD. Methods: Twenty-two patients with first-episode MDD accepted an 8-week course of taVNS treatment. Resting-state functional magnetic resonance imaging (rs-fMRI) scans were performed before and after treatment. Voxel-based analyses were performed to characterize spontaneous brain activity. Healthy controls (n=23) were recruited to minimize test-retest effects. Analysis of covariance (ANCOVA) was performed to ascertain treatment-related changes. Then, correlations between changes in brain activity and the Hamilton Depression Rating Scale (HAM-D)/Hamilton Anxiety Scale (HAM-A) remission rate were estimated. Results: Significant group-by-time interactions on voxel-based analyses were observed in the inferior ventral striatum (VSi) and precuneus. Post-hoc analyses showed that taVNS inhibited higher brain activity in the VSi, while upregulating it in the precuneus. Functional connectivity (FC) between the VSi and precuneus decreased. Positive correlations were found between the HAM-D remission rate and changes in brain activity in the VSi. Conclusion: taVNS reduced the FC between VSi and precuneus by normalizing the abnormal spontaneous brain activity of VSi in first-episode MDD patients.