The present invention is a non-transgenic rodent exhibiting signs and symptoms associated with Alzheimer's disease. The animal of this invention is produced by acutely injecting .beta.-amyloid (25-35) peptide into the lateral ventricles of a rodent. Animals produced in accordance with this invention can be used in a method of identifying a therapeutic agent for the prevention or treatment of Alzheimer's disease and to study the etiology of this disease.