Amyloid Plaque and Tangle Imaging in Aging and Dementia

Inclusion Criteria: * Agreement to participate in a clinical and brain imaging study * Age 30 years or older * No significant cerebrovascular disease - modified Ischemic Score of ≤ 4 * For volunteers with MCI or dementia, there must be a family member or potential caregiver available * Adequate visual and auditory acuity to allow neuropsychological testing * Screening laboratory tests and ECG without significant abnormalities that might interfere with the study. Exclusion Criteria: * Evidence of neurologic or other physical illness that could produce cognitive deterioration; in addition to a physical and neurological examination, volunteers will be screened for Parkinson's disease * History of myocardial infarction within the previous year or unstable cardiac disease * Uncontrolled hypertension (systolic BP\>170 or diastolic BP\>100), history of significant liver disease, clinically significant pulmonary disease, diabetes, or cancer * Major psychiatric disorders, such as bipolar disorder or schizophrenia * Because medications can affect cognitive functioning, volunteers needing medicines that could influence psychometric test results will be excluded; use of any of the following drugs will also exclude volunteers: centrally active beta-blockers, narcotics, clonidine, anti-Parkinsonian medications, benzodiazepines, systemic corticosteroids, and medications with significant cholinergic or anticholinergic effects, anti-convulsants, or warfarin * Current diagnosis or history of alcoholism or drug dependence * Evidence of untreated depression as determined by a HAM-D (Hamilton, 1960) score of ≥ 12 (17-item version) or untreated anxiety by a score of ≥ 8 on the Hamilton Anxiety Scale (HAM-A; Hamilton, 1959) * Use of any investigational drugs within the previous month or longer, depending on drug half-life * Contraindication for MRI scan (e.g., metal in body, claustrophobia)