The brain awake surgery has recently boomed in neurosurgical oncology but also in epilepsy surgery. The goal of awake surgery is to allow a more precise localization of sensorimotor functions, languages and cognitive to better respect them. Indeed, the interindividual anatomo-functional variations, the lack of specificity of functional explorations radiological magnetic or nuclear, as well as the reorganization of the areas involved in these functions (mechanisms of brain plasticity) in epileptic patients or patients with cerebral tumor do not allow to identify them in preoperatively. Brain awake surgery allows an analysis and a precise real-time identification of areas and networks involved in these functions through a direct electrical stimulation (inhibitory or activatory). Thus, this surgical technique has become a gold standard in surgery of brain lesions located in functional areas.