This study is being done to look at the relationship between brain structure and brain function in patients with epilepsy or focal brain lesions (abnormal areas) that require surgery. This study will look at an imaging technique called magnetic resonance imaging (MRI) for looking at the brain. Specifically, the study will look at functional MRI, which is an imaging technique that can map brain function by taking pictures of the brain as it performs different tasks such as reading, thinking, or moving a body part and diffusion tensor imaging (DTI), which will look at brain structure. These types of imaging may help us learn more about different areas of the brain and how those areas of the brain are used in children with epilepsy. We plan to study 30 children with epilepsy.