Hemispheric laterality in contextual recognition

Hemispheric dominance in contextual recognition is now under discussion. Au ditory event-related potentials (ERPs) with a contextual decision task were recorded to study hemispheric dominance by using the wave energy and ampli tudes of N400 for eight native volunteers. Two types of 80 sentences with f our clauses were used as the structure: [subject]+[object or complement]+[o bject]+[two-syllable verb]. One type was congruent and the other deviated a t the terminal clause as an incongruent sentence. Twenty-one channel ERPs w ere triggered at the verbs and recorded during -200 and 1,000 ms, with a no ncephalic reference from 0.05 to 30 Hz. The wave energy was calculated as m ean square potentials and was normalized with the background activity (pret rigger 200 ms). The amplitudes of N400 showed significant differences betwe en the incongruent and congruent sentences, but the hemispheric dominance f or the amplitudes of N400 was not significant between the incongruent and c ongruent sentences. Reaction times with the index finger to respond to the deviated verbs were 470.0 (mean)+/-42.5 (SD) ms. The maximum normalized wav e energy within the mean reaction time showed significant differences betwe en the incongruent and congruent sentences, and the left hemispheric energy was shown to be significantly higher than the right one.