Neural networks and the anti-inflammatory effect of transcutaneous auricular vagus nerve stimulation in depression

• Published in: Journal of neuroinflammation Vol. 17; no. 1; pp. 54 - 11
• Main Authors: Liu, Chun-Hong, Yang, Ming-Hao, Zhang, Guang-Zhong, Wang, Xiao-Xu, Li, Bin, Li, Meng, Woelfer, Marie, Walter, Martin, Wang, Lihong
• Format: Journal Article
• Language: English
• Published: London BioMed Central 12.02.2020; BioMed Central Ltd; BMC
• Subjects: Acupuncture; Amygdala; Anti-inflammation; Biomedical and Life Sciences; Biomedicine; Brain; Brain network; Care and treatment; Circuits; Cytokines; Depression; Depression (Mood disorder); Immune system; Immunology; Inflammation; Mental depression; Neural circuitry; Neural networks; Neurobiology; Neurology; Neurosciences; Physiological aspects; Prefrontal cortex; Reinforcement; Review; Spleen; Testing; Transcutaneous auricular vagus nerve stimulation; Tumor necrosis factor-TNF; Vagus nerve; Vagus nerve stimulation; China; Depression; Transcutaneous auricular vagus nerve stimulation; Vagus nerve; Brain network; Anti-inflammation
• ISSN: 1742-2094; 1742-2094
• DOI: 10.1186/s12974-020-01732-5

Transcutaneous auricular vagus nerve stimulation (taVNS) is a relatively non-invasive alternative treatment for patients suffering from major depressive disorder (MDD). It has been postulated that acupuncture may achieve its treatment effects on MDD through suppression of vagal nerve inflammatory responses. Our previous research established that taVNS significantly increases amygdala–dorsolateral prefrontal cortex connectivity, which is associated with a reduction in depression severity. However, the relationship between taVNS and the central/peripheral functional state of the immune system, as well as changes in brain neural circuits, have not as yet been elucidated. In the present paper, we outline the anatomic foundation of taVNS and emphasize that it significantly modulates the activity and connectivity of a wide range of neural networks, including the default mode network, executive network, and networks involved in emotional and reward circuits. In addition, we present the inflammatory mechanism of MDD and describe how taVNS inhibits central and peripheral inflammation, which is possibly related to the effectiveness of taVNS in reducing depression severity. Our review suggests a link between the suppression of inflammation and changes in brain regions/circuits post taVNS.