Is the N400 category-specific? A face and language processing study.

N400 event-related potential (ERP) components have been observed during semantic incongruity detection in language, face identity and/or expression. However, it is still unclear whether semantic processing is functionally equivalent, since no study has directly investigated within the same participants the occurrence of the N400s for language and faces. We recorded ERPs while subjects performed incongruity detection on words, facial identities and facial expressions, with conditions matched to involve context integration. N400s were identified on central-parietal electrodes only for language and face identity processing. Scalp topographies of these N400s differed but a LORETA inverse solution identified a common functional generator in the left lateral frontal cortex, suggesting a general role of this brain region in selecting and contextually integrating semantic information.