Intraoperative brain mapping techniques are utilized in neuro-oncology to maximize the extent of tumor resection and seizure control, and minimize the operative morbidity. Direct stimulation mapping of the cortex and subcortical descending motor pathways will localize the rolandic cortex, dominant language speech zones and motor tracts in the internal capsule, cerebral peduncle and corticospinal tract/anterior horn cells. Electrocorticography identifies epileptogenic areas that histologically are distinctly devoid of neoplastic infiltration. Seizure control is maximal when seizure foci are resected in addition to the tumor nidus.