Epilepsy is a variety of symptoms caused by repeated abnormal discharges of nerve cells in the brain. Abnormal discharges can originate in different parts of the brain, and they can spread and conduct on the surface of the brain, with a wide range of clinical manifestations due to different sites of origin and inconsistent pathways. In epilepsy, abnormal discharges can start in one part of the cerebral cortex and spread only in a small area, or they can spread to other areas of the brain, which is clinically manifested as focal seizures. Therefore, the area where the abnormal discharge starts is the epileptic focus that causes the seizure. If the seizure causing focus can be surgically removed, the seizure can be eradicated and controlled.