Because PD patients display constipation prodromal symptoms but not stomach disorders, in our most recent study, we chose to inoculate preformed fibrils into the gut wall instead of the stomach, though the latter contains more vagus nerves than the former and revealed that colonoscopic injection of α-Syn N103/Tau N368 fibrils transport into the brain, resulting in PD-like pathologies and motor dysfunctions45. The gene discussed is MAPT; the disease is Parkinson disease.