EVENT-RELATED BRAIN POTENTIALS WHILE ENCOUNTERING SEMANTIC AND SYNTACTIC CONSTRAINT VIOLATIONS

The objective of the present study was to delineate brain-electrical c orrelates of semantic and syntactic integration processes during langu age comprehension. Twenty-eight subjects were engaged in a lexical dec ision task. The target item (a legal word or a pseudoword) was always preceded by a prime consisting of a sentence fragment that provided a particular context. With respect to the prime a word target could be e ither a correct completion, a violation of a semantic selection restri ction, or a violation of a syntactic subcategorization rule. An N400-l ike wave was elicited by both types of deviations. Syntactic anomalies evoked a negative shift predominantly over the anterior scalp with a preponderance over the left hemisphere, while semantic anomalies were accompanied by a much more widespread negativity with the maximum over posterior temporal areas. The amplitude of the semantic violation eff ect was found to be related to the strength of the priming constraints . The topographic difference is consistent with the idea that syntacti c and semantic aspects of comprehension are handled by different neura l subsystems.