The principle of epilepsy surgery is to remove the brain tissue at the site of the epileptic focus to prevent the generation of abnormal epileptic discharges, however, some important functional brain areas cannot be removed, otherwise complications of surgery will arise. Functional areas include the functional brain areas responsible for language, the central brain area responsible for limb movement and sensation, etc. Therefore, when epileptic foci overlap with or are very close to these functional areas, it is important to clearly delineate the boundaries between the epileptic foci and the functional areas. For this reason, some patients undergo additional preoperative tests, for example, to determine the dominant hemisphere for memory and language, an amytal test, which involves injecting a short-acting anesthetic into the internal carotid artery on each side to briefly inhibit brain function on one side, is required to simulate whether brain dysfunction will be demonstrated after partial brain tissue is removed from one side, and sometimes the function of different brain tissues within a very fine range needs to be This may be done using functional MRI to identify specific brain gyrus structures in relation to somatic movement and sensation, and may also help to identify the location of language areas. In addition, transcranial rapid magnetic stimulation is sometimes used to temporarily interfere with the function of a particular area of the brain using a rapidly shifting magnetic field to determine the function of certain parts of the brain, which can also help determine the function of different brain areas. In order to determine the range of functional areas more precisely, it is necessary to use intracranial electrodes for recording to determine the various sensory, visual, and auditory sensations of the somatic body to induce the corresponding parts in the brain, and it is also possible to use weak electric currents to stimulate different parts of the brain on both sides to determine the functional areas of the brain according to the different responses of the patient. Therefore, before locating the functional areas of the brain for some patients, the surgery cannot be performed casually, otherwise it will bring serious consequences.