This study will look for evidence that a virus called HHV-6B may be related to seizures and to a form of brain injury called mesial temporal sclerosis that is associated with seizures. The study will use new, more sensitive brain scans to try to detect brain regions that might be affected by the virus and will examine cerebrospinal fluid (CSF, the fluid that bathes the brain and spinal cord) for evidence of the virus as well.

Healthy volunteers and people with seizures uncontrolled by anti-epileptic drugs who are between 18 and 45 years of age may be eligible for this study. Candidates are screened with a physical examination and laboratory tests.

Participants undergo the following procedures:

• PET scan. This test uses a radioactive chemical called 18FDG, which is detected by the PET scanner to obtain images of the brain. The subject lies on a table with his or her head positioned in the scanner. A swimming cap with a small light reflector is placed on the head to monitor the position of the head during the scan. A catheter (plastic tube) is inserted into an artery at the wrist or elbow crease of the arm for obtaining blood samples during the scan, and a second catheter is placed in a vein in the other arm for injecting the 18FDG. The scan takes up to 2 hours. A second scan may be done over an additional 15 minutes.
• MRI. This test uses a strong magnetic field and radio waves to obtain images of the brain. The subject lies on a table that can slide in and out of a metal cylinder surrounded by a magnetic field. Most scans last between 45 and 90 minutes.
• Lumbar puncture. The subject sits upright or lies on a table with the knees curled to the chest for this procedure. A local anesthetic is injected to numb the skin and a needle is inserted in the space between the bones in the lower back where the CSF circulates below the spinal cord. A small amount of fluid is collected through the needle.
• Blood tests. About 4 tablespoons of blood are drawn for viral tests.

Objectives: 1) to attempt to detect specific patterns of hippocampal injury in patients with temporal lobe epilepsy that may be associated with HHV-6B infection; 2) To attempt to detect evidence for persistent HHV6 infection in CSF in patients with refractory temporal lobe epilepsy. 3) to obtain preliminary pilot data on the ability of high resolution structural to detect abnormalities in epilepsy patients not seen with standard scanners.

Study Population: 45 patients with localization-related epilepsy; 45 healthy volunteers

Design: 1) imaging with a 7T MRI magnetic resonance scanner; 2) Lumbar puncture. 3) blood sampling

Main outcome measure: 1) Detection of evidence for HHV6 infection in CSF

• INCLUSION CRITERIA:

Patients will be avaluated for participation under screening protocol 01-N-0139.

Patients

Male and female subjects age 18 to 55

Subjects with seizures uncontrolled by antiepileptic drugs

Subjects with no other illnesses, or taking other substances or medicines that could interfere with the study

Healthy Controls

Male and female subjects age 18 to 55.

EXCLUSION CRITERIA:

Patient

Subjects who are pregnant or breast feeding.

Subjects with any medical condition that could interfere with the study.

Subjects who are taking drugs that significantly reduce blood clotting such as Coumadin or Warfarin.

Healthy Volunteers

Subjects who are pregnant or breast feeding

Subjects who have any medical condition or be taking any substance or medication that could interfere with the study

Subjects who are taking drugs that significantly reduce blood cloting such as Coumadin or Warfarin