BDNF and migraine disorder: Based on our findings that the lung microbiome can activate pulmonary vagal afferent nerves through the pulmonary BDNF‐TrkB pathway to regulate migraine, we administered 7,8‐Dihydroxyflavone (7,8 DHF), a TrkB agonist, via intratracheal injection to the migraine group (Figure6A).