Electrophysiological correlates of conventional metaphor, irony, and literal language processing – An event-related potentials and eLORETA study

Conventional metaphor, irony, and literal language processing were compared. Thirty right-handed participants (21-34 years) performed a sequential-statement ERP-paradigm. A left-frontal Late Anterior Negative Slow Wave (LANSW, 450-1000 ms) was significantly greater for metaphors and by visual tendency greater for irony, compared to literal statements. A centroparietal N400 (300-450 ms) and a centroparietal right-dominant "Late N400" (450-600 ms) were by statistical and visual tendency greater for metaphors. Left PCC and left lingual gyrus activity was significantly higher in metaphors compared to literal statements (eLORETA; 450-1000 ms). A statistical trend indicated higher parahippocampal gyrus activity in metaphors and ironies. N400 results are discussed considering changing processing techniques and a renewed semantic conflict. The Late N400 was associated with the construct of "associativeness". The LANSW was related to metaphorical mapping, frame-shifting processes, integration of meanings, and memory processes. eLORETA results were discussed considering metaphorical mapping, creation of mental images, conventionality, valence, memory processes, and divergent thinking.