EVENT-RELATED BRAIN POTENTIALS DURING NATURAL SPEECH PROCESSING - EFFECTS OF SEMANTIC, MORPHOLOGICAL AND SYNTACTIC VIOLATIONS

The present study investigated different aspects of auditory language comprehension. The sentences which were presented as connected speech were either correct or incorrect including a semantic error (selection al restriction), a morphological error (verb inflection), or a syntact ic error (phrase structure). After each sentence, a probe word was pre sented auditorily, and subjects had to decide whether this word was pa rt of the preceding sentence or not. Event-related brain potentials (E RPs) were recorded from 7 scalp electrodes. The ERPs evoked by incorre ct sentences differed significantly from the correct ones as a functio n of error type. Semantic anomalies evoked a 'classical' N400 pattern. Morphological errors elicited a pronounced negativity between 300 and 600 ms followed by a late positivity. Syntactic errors, in contrast, evoked an early negativity peaking around 180 ms followed by a negativ ity around 400 ms. The early negativity was only significant over the left anterior electrode. The present data demonstrate that linguistic errors of different categories evoke different ERP patterns. They indi cate that with using connected speech as input, different aspects of l anguage comprehension processes cannot only be described with respect to their temporal structure, but eventually also with respect to possi ble brain systems subserving these processes.