 Design: This is a neuroimaging study, using positron emission tomography PET with 11Cflumazenil, to measure GABAA binding potential, and 18Ffluorodeoxyglucose, to measure glucose utilization reflective of neuronal glutamate release. Magnetic resonance spectroscopy MRS will be used to measure GABA and glutamate in the mesial temporal cortex and corroborate the PET results. Structural magnetic resonance images MRI will be obtained for MRS localization and partial volume correction of PET images. 