Eligibility CriteriaINCLUSION CRITERIA:
The desired age range is 18 to 55 years.
Subjects will have no history of head injury or other neurological disease and must not be taking any medication.
Female subjects of childbearing potential will be administered a pregnancy test; these subjects will not be eligible for the study requiring 2 scans.
All volunteers will read and sign the consent form.
Patients will be selected from among those referred to the Clinical Epilepsy Section, NINDS for evaluation.
Patients with evidence of a progressive intracranial process, who are taking any drugs (except AEDs) that might affect the results, or active systemic disease will be excluded.