Abstract

Arguments about the existence of language-specific neural systems and specifically about the indipendence of syntactic and semantic processing have focused on the event-related brain measures (ERPs) as tool to monitoring, moment-by-moment, the cognitive processes implicated. Some theoretical models predict that qualitatively different processing principles for syntax and semantic arise from the existence of qualitatively different neural processing. Other models have proposed that a semantic representation is assembled directly, without an intermediate syntactic representation. ERPs were recorded from 10 electrodes while subjects saw (Experiment 1) or listened (Experiment 2) to sentences containing semantic or syntactic anomalies. Final-word that was inconsistent with the sentence context elicited a negative-going wave at about 400 ms postimulus, whereas final-word incongruous with the grammatical structure (not agreement subject-verb) elicited a positive-going wave about 600 ms postimulus. In the current experiments (1 and 2), the available evidence indicates that the ERP response to semantic anomalies is at least partially distinct from the ERP response to syntactic anomalies and that a syntactic parser is a plausible process included in sentences comprehension. No difference were found based on the perceptive modality of the stimulus (visual or auditory) nor different ERP correlates as a function of the task-relevance (esplicit/ implicit task induction). Amodality and task independence for both N400/P600 effects were discussed.