Alzheimer's disease, Parkinson's disease and Lewy body disease are the
most commonly found neurodegenerative disorders in the elderly. The
invention is a transgenic mouse that contains two transgenes, human
.alpha.-synuclein and human amyloid precursor protein, which are
responsible for the formation of the neuritic plaques, Lewy bodies and
neurodegeneration seen in the above mentioned diseases. The transgenic
mouse is an accurate model for disease by both functional and
pathological assays.