Of five epilepsy patients with implanted subdural electrodes, electrical cortical stimulation (ECS) on left posterior inferior frontal gyri (LPIFG) of dominant language hemisphere, did not elicit language production related symptoms. These patients were then subjected to six language production tasks with simultaneously electrocorticographic (ECoG) recording. Dada analysis revealed several cortical sites showed event-related cortical high gamma activities. These sites were linked to certain functions, e.g., auditory, visual, and sensorimotor, according to their different activation patterns among tasks. Sites labeled as sensorimotor-related by ECoG showed high accordance with those identified via ECS. Yet ECoG identified few extra crucial sites in LPIFG either. These results demonstrated consistency between ECS and ECoG and reaffirmed the utility of ECoG in preoperative functional cortical mapping. (C) 2017 Elsevier Ltd. All rights reserved.