Figure 2.

Functional anatomy of taVNS in requlating cardiac activity. After activating the NTS and DMN, through efferent vagus nerve, taVNS reduces the expression of TGF-β1 by regulating the reninangiotensin-aldosterone system, thereby inhibiting the formation of angiotensin II and induce the expression of TIMP-1 and decrease the activation of the MMP-9. Collagen I and III synthesis are reduced, preventing distal heart fibrosis and glial deposition to protect heart function. DMN, dorsal motor nucleus; MMP-9, matrix metallopeptidase 9; NTS, nucleus tractus solitarius; taVNS, transcutaneous auricular vagus nerve stimulation; TGF-β1, transforming growth factor β1; TIMP-1, tissue inhibitors of metalloproteinase 1.