The objective of the study is to acquire a database of Single Photon Emission Computed Tomographic (SPECT) studies of the brains of normal human subjects in resting and concentrating states. The database will provide a basis for subsequent investigation of meaningful brain differences between clinical and normal subject groups

See brief summary.

Inclusion Criteria:

The study seeks to recruit 100 normal human subjects between ages 10 and 90 for SPECT brain imaging. Subjects will initially be screened for psychiatric and other major illnesses with a screening questionnaire; they will also be given a standard DSM-4 computer-administered questionnaire (The DISC for children and teens and the SCID for adults). They will also meet individually with a psychiatrist or psychological assistant for a screening interview.

Exclusion Criteria:

1. Suicidal thinking or behavior
2. Any psychiatric diagnosis assignable under contemporary DSM nosology
3. Unstable medical condition
4. epilepsy, serious head injury, or other significant neurological disorder or use of central nervous system medication.
5. Dementia, mental retardation, or coma
6. Substance abuse or alcoholism
7. Unreliability or inability to adhere to the requirements of the study
8. Inability to personally tolerate the requirements of the study
9. Significant exposure to occupational, diagnostic, or therapeutic radiation within the prior year
10. Pregnancy or breast-feeding
11. A first-degree relative meeting any of criteria 1 through 6.

The study seeks to recruit 100 subjects between ages 10 and 90 for SPECT brain imaging.