Clinical features and significance of negative motor response in intraoperative language mapping during awake craniotomy

The negative motor area and anterior and posterior language areas were localized by intraoperative electrical cortical stimulation under the awake condition to evaluate the clinical significance of these areas. Thirty-seven awake craniotomies with language mapping were performed in 36 patients with brain tumors. The negative motor area was determined in 17 cases, and the anterior and posterior language areas were found in 12 and 6 cases, respectively. The negative motor area was located in the precentral gyrus inferior to the orofacial motor area in 16 cases, and in the inferior frontal gyrus anterior to the orofacial motor area in one case. Both the negative motor area and the anterior language area were determined in 8 cases. Anterior language areas in these 8 cases were located anterior and/or inferior to the negative motor areas. The negative motor area is an easily determined, important landmark for intraoperative language mapping.