Alzheimer's Disease (AD) is the most common form of neurodegenerative disease and was first diagnosed by the German psychiatrist, Alois Alzheimer in 1906. AD is characterized pathologically by the presence of senile plaques, neurofibrillary tangles, and massive loss of neurons in selected brain regions. The amyloid peptides deposited in senile plaques are produced by proteolytic processing of amyloid precursor protein.