Figure 2.

In healthy conditions, normal vagal tone can protect gut barrier and inhibit macrophages releasing pro-cytokine, TNF-α. While in response to stressors, vagal tone is depressed, promoting gut barrier impairment and releasing of TNF-α. Compromised gut barrier facilitate bacterial translocation, which activates immune system and induces immune mediators. Through the circulation system, gut and system inflammation ultimately results in neuroinflammation. TNF-α, tumor necrosis factor alpha. By Figdraw.