This study aims to better understand how epilepsy alters brain function through neuroimaging of healthy people and people with epilepsy. The study investigates how changes in brain metabolism (sugar consumption, measured by positron emission tomography \[FDG-PET\], and blood flow, measured by functional magnetic resonance imaging \[fMRI\]) relate to abnormal interictal electrical activity associated with epilepsy (measured by electroencephalography \[EEG\]). The study will also compare how the three imaging modalities localize regions of abnormal function in the brain.