The goal of this paper was to overview functional brain mapping for intraoperative motor evoked potentials recorded from muscles (cortico-muscular MEPs) and corticospinal MEPs recorded from the cervical epidural space (corticospinal MEPs) to assess their efficacy in the intraoperative monitoring of motor function. Validation for preoperative mapping and intraoperative evaluation with mapping-based cortico-muscular MEPs were discussed. Patients showed a substantial decrease in the amplitude of the muscle MEP without deterioration in the corticospinal D wave, and exhibited severe immediate postoperative motor dysfunction. This indicates dysfunction of the cortical gray matter, including the motor cortices and/or supplementary motor or other extra-motor cortical areas, which are supposed to configuration of I waves. Multimodal method (DTI, fMRI) combined with TMS-based preoperative mapping of primary motor cortex could helpful for integrated general intraoperative evaluation.