The clinical-scientific core is intended to be resource for all of the projects in this application. The Memory Disorders Clinic, a regional resource, in which Drs. Schneck, Filley, Kelly and Morgenstern work, will serve as a primary focus for identification of patients with probable AD who can then be studied as needed in Projects 2, 4 and 5. Elderly patients with dementia can also be made available to the projects from nursing homes in the Denver area, through the local Alzheimer Associations, and from the Geriatric Clinics at the Veterans Administration Hospital and University Hospital (Dr. Morgenstern). Patients with a variety of neuropsychiatric abnormalities can be derived from the Ft. Logan Mental Health Center and the Colorado State Hospital in Pueblo, where Dr. Kelly is a weekly consultant, for study in Project 4. Appropriate consent will be obtained from all patients. Neuropathological support for the projects will be supplied by Drs. Kleinschmidt-DeMasters and Schneck. AD autopsy material, as fresh as possible, will be supplied to investigators in Projects 1 and 5 when available, as will tissue from PD patients when available for Project 3. Appropriate brain biopsy material when available can be supplied for Projects 1 and 5. Statistical assistance and analyses for all projects will be obtained from Dr. Zerbe. Secretarial support will be used to correlate patient appointments, compile patient records and a data base, serve as a central focus for referrals for physicians and the community, and correlate neuropathological requirements and data. Manuscripts, reports and records from all investigators in all projects will be centralized in this secretarial office.