The purpose of this experiment is to demonstrate the mechanism of Lewy body aggregation and formation in DMV by gene modification and injection of exogenous preformed fibrils, and how this relates to Parkinson's disease. Through a series of work such as cardiac perfusion, frozen section, and immunohistochemical staining, the existence of cholinergic neurons and Lewy bodies at the DMV was finally confirmed by 63x laser confocal microscopy, which explained the symptoms of the digestive system during the early stage of Parkinson's disease.