Neural representations of sentence processing: event-related components and oscillations

Event-related fields (ERFs) and rhythmic oscillations represent two measures that quantify the electrophysiological brain activity in response to a stimulus. Using MEG, we analyzed both measures in a sentence processing task to clarify the relationship between these measures. We presented participants with sentences and matched word sequences. Results indicated a partial spatial overlap on the sensor level between the two measures, with a wider area of activity present for oscillations. Within the common region, the effect for each measure was in a different time window. Relating the results to the literature reveals furthermore a functional distinction between the results observed in the two respective measures. The sustained left dominant eventrelated field peaking around 400 ms is most likely related to lexical processing whereas the rhythmic activity of 13-30 Hz (beta rhythm) captures some aspects of sentence unification. We conclude that the ERFs and the rhythmic activity provide a complementary view of brain function during sentence level language processing.