Résumé
The role of the frontal lobe in cross-modal visual–auditory processing has been documented in experiments using incongruent/congruent paradigms. In this study, 4 patients with left frontal World Health Organization Grade II glioma were assessed during pre-, intra-, and postoperative sessions with picture-naming and verbal–visual task requiring judgment of congruence between pictures and words. During awake brain surgery, the naming and cross-modal tasks were coupled with electrical stimulation inactivating restricted specific regions. For all patients, focal brain stimulation in the dorsolateral prefrontal cortex elicited picture–word matching disturbances but no naming impairment, and the elicited errors exclusively appeared in incongruent and not congruent conditions. The dissociation observed between correct picture naming and disturbed cross-modal judgment shows that electrical stimulation of a discrete cortical area within the left dorsolateral prefrontal cortex can inhibit the simultaneous processing of visual–verbal information without disturbing larger networks involved in the naming process.