Extraoperative electrical cortical stimulation: characteristics of motor responses and correlation with anatomical motor strip

Background: Extraoperative cortical stimulation (CS) of motor function is used to map the primary motor cortex in the setting of preoperative evaluation for epilepsy surgery. We aimed to characterize the properties and stimulation thresholds of extraoperative CSs with respect to the anatomical area stimulated. Furthermore, we studied the occurrence of afterdischarges (ADs) and the latency between cortical stimulation onset and occurrence of clinical signs in primary motor cortex compared to other cortical areas. Methods: Retrospective review of 1496 bipolar extraoperative CSs in 4 patients with frontal lobe epil…