Fluency tasks generate beta-gamma activity in language-related cortical areas of patients during stereo-EEG monitoring

•Fluency task induce intracranial EEG frequency changes.•Focal increase in the beta-gamma frequency power range identified Broca area.•Intracranial EEG recording can help to identify and study language areas.

A quantitative method was developed to map cortical areas responsive to cognitive tasks during intracerebral stereo-EEG recording sessions in drug-resistant patients candidate for epilepsy surgery. Frequency power changes were evaluated with a computer-assisted analysis in 7 patients during phonemic fluency tasks. All patients were right-handed and were explored with depth electrodes in the dominant frontal lobe. We demonstrate that fluency tasks enhance beta-gamma frequencies and reduce background activities in language network regions of the dominant hemisphere. Non-reproducible changes were observed in other explored brain areas during cognitive tests execution.