Tau Pet Imaging in the Aging Brain Cohort Dedicated to Diversity Study

Inclusion Criteria:

1. Males and females African Americans ≥ 65 years of age.

2. Part of the ABCD2 longitudinal cohort, protocol 844047, of the PMC/ADCC withconsensus conference designation of normal cognition.

3. ABCD2 longitudinal visit must be completed or scheduled to be completed within 1year prior to the [18F]AV-1451 TAU PET scan.

4. A brain MRI must be performed within 1 year prior to their study [18F]AV-1451 TAUPET scan date and be deemed of adequate quality that the scan may be used for studyanalysis, including 3T high-resolution imaging of medial temporal lobe structures.

5. An amyloid PET scan completed or scheduled within 1year of their study [18F]AV-1451

6. Women must be post-menopausal or surgically sterile.

Exclusion Criteria:

1. Have any medical or psychiatric conditions that, in the opinion of the investigator,would compromise the subject's safety or successful participation in the study,including major depression and prior head trauma.

2. Have evidence of structural abnormalities such as major stroke or mass on MRI thatis likely to interfere with analysis of the PET scan.

3. Inability to tolerate or contraindication to imaging procedures in the opinion of aninvestigator or treating physician.

4. Have a history of significant ongoing alcohol or substance abuse or dependence basedon self-report.

5. Women of child bearing potential

• The inclusion / exclusion criteria will be ascertained through self-report inconjunction with any medical history available through the participant'smedical or research records (EPIC or the ADC database)*