MAPT and Alzheimer disease: Here, we evaluated the behavioral phenotypes of the tauopathy mouse model from 3 months of age, before they developed NFT-like tau pathology, neuronal cell death and motor weakness, and delineated a novel behavioral phenotype, increased prepulse inhibition (PPI), that is observed in the prodromal stage of AD, at the earliest stages of disease onset in our tauopathy model mice.