INCLUSION CRITERIA:
All subjects must be healthy and aged 18-65 years.
EXCLUSION CRITERIA:
PART 1 (WHOLE BODY IMAGING STUDIES):
1. Current psychiatric disease, substance abuse or severe systemic disease based on history and physical exam, poor vision or hearing.
2. Laboratory tests with clinically significant abnormalities.
3. Prior participation in other research protocols or clinical care in the last year such that radiation exposure including that from this protocol would exceed a half of the annual limits. Because human dosimetry of (R)-[(11)C]rolipram has been estimated using rhesus monkeys, the total exposure including that from the (R)-[(11)C]rolipram whole body imaging study will be limited to a half of the RSC guidelines.
4. Pregnancy and breast feeding.
5. Positive HIV test.
6. Positive urine drug screen.
PART 2 (TEST RETEST BRAIN IMAGING STUDIES):
1. Current psychiatric disease, substance abuse or severe systemic disease based on history and physical exam, poor vision or hearing.
2. Laboratory tests with clinically significant abnormalities.
3. Prior participation in other research protocols or clinical care in the last year such that radiation exposure would exceed the annual limits. Results of part 1 will be used to calculate total radiation exposure within a year.
4. Pregnancy and breast feeding.
5. Claustrophobia.
6. Presence of ferromagnetic metal in the body or heart pacemaker.
7. Positive HIV test.
8. A history of brain disease.
9. Positive urine drug screen.