Animal models attempt to mimic human diseases and thus allow testing of therapeutic strategies as well as the investigation of the disease course and underlying pathophysiology in a manner that is impractical or unethical in humans. Transgenic models now dominate approaches to animal modeling of human neurodegenerative diseases, including AD. In one sense, the models are limited by their requirement for a genetic modification. However, the discovery of genes for familial forms of AD has allowed transgenic models to be created that reproduce many critical aspects of the disease. These models have improved our understanding of the disease pathogenesis and have led to new therapeutic approaches. They will, without a doubt, continue to play central roles for years to come in preclinical testing and be used as tools for developing insight into the biological basis of AD.
