Neural basis of sentence processing in which incoming words form a sentence.

This study examined the neural basis underlying the sequential involvement of sentence processing and determined the point at which the processing cost for an object-initial sentence was observed. We presented each phrase in a Japanese object-initial sentence to Japanese participants one by one using an event-related functional MRI technique and compared with our previous subject-initial experiment. We found that the left lingual gyrus was activated upon presentation of the first noun phrases, and the left inferior frontal gyrus upon presentation of the second noun phrases. The processing cost for an object-initial sentence was observed during verb recognition. Our results suggest that the syntactic complexity of an object-initial sentence is processed by the human brain upon verb recognition.