Figure 1. Mechanisms by which gut bacteria maintain a healthy balance in the gut-brain axis.

Hodan Qasim, the first author, created this figure. The paper Gut-brain Axis and migraine headache: a comprehensive review [3]​​, an article distributed under the terms of the Creative Commons Attribution 4.0 International License, served as the source for the figure.

CGRP: Calcitonin gene-related peptide, CRH: Corticotrophin-releasing hormone, HPA: Hypothalamic pituitary adrenal axis, LPS: Lipopolysaccharides, IL: Interleukin, TNFα: Tumor necrosis factor-alpha