For instance, EA improves neuropathic pain by blocking BDNF/TrkB (tropomyosin-related kinase B) signaling pathway-mediated central sensitization (9), and acupuncture activates PI3K (phosphoinositide 3-kinases) /Akt (protein kinase B) and MEK (mitogen activated protein kinase kinase) /ERK (extracellular signal–regulated kinases) signaling pathways downstream of BDNF, thereby promoting the survival of dopaminergic neurons and improving the symptoms of Parkinson’s disease (10). Here, NTRK2 is linked to Parkinson disease.