The Role of Serotonin in Seizures

Objective: To study serotonergic transmission in epilepsy and its relation to cerebral glucose metabolism, mesial temporal sclerosis, and depression. Study population: Patients with localization-related epilepsy with and without depression, and generalized epilepsy, and normal controls, ages 18-60. Design: This is a neuroimaging study using positron emission tomography with a 5HT(1A) receptor ligand, 18F-FCWAY, a serotonin transporter ligand, 11C-DASB, and 15O-H2O for cerebral blood flow estimation. Patients will have measurements of cerebral glucose metabolism using 18F-FDG as well. Magnetic resonance imaging will be performed for examination of hippocampal structure and partial volume correction. Screening for depression will be performed by NIMH investigators. We will measure cortisol and ACTH levels, which may affect hippocampal structure and function. Testing for genetic markers that may predict serotonin transporter activity and depression will be performed. Outcome measures: 5HT(1A) receptor binding, serotonin transporter activity, cerebral blood flow, and, in patients, glucose metabolism and hippocampal structure. Patients will be stratified by seizure type and depression ratings.