Magnetoencephalography evidence of semantic violations in auditory sentence comprehension by native speakers of Japanese

The present study examined whether both vowel-shortening and vowel-lengthening violations would elicit a semantic field component in native speakers of Japanese, and whether such a component would also be observed in phonemic violations. Stimuli contained semantically correct and incorrect versions of two types of vowel duration (shortening and lengthening), and semantically deviant words with phonemic violations. Five hundred Japanese sentences were aurally presented to each subject, while neuromagnetic fields were recorded using a dual 37-channel gradiometer system. A prominent magnetic field component, peaking at around 400 ms after the onset of the target word, was elicited by vowel-shortening and phonemic violations in the left hemisphere only, but not vowel-lengthening violations. This semantic field component was labeled the 'SeF-M400'. The results suggest that auditory semantic mechanism is more sensitive to vowel-shortening violations than to vowel-lengthening violations. (C) 2002 Published by Elsevier Science Ireland Ltd.