Magnetoencephalography Reveals Mismatch Field Enhancement from Unexpected Syntactic Category Errors in English Sentences

•The syntactic category error of bare infinitival structures against structural predictions was noticed robustly in MEG.•This error activated the anterior superior temporal sulci in the left hemisphere with a peak latency of approximately 200 ms. The type of syntactic operations that increase neuronal activation in humans as a result of syntactically erroneous, unexpected lexical items in hearing sentences has remained unclear. In the present study, we used recordings of magnetoencephalographic (MEG) activity to compare bare infinitive and full infinitive constructions in English. This research aims to identify the type of syntactic deviance that may trigger an early syntax-related mismatch field (MMF) component when unexpected words appear in sentences. Six speakers of English as a first language were presented with auditory stimuli of sentences or words in a passive odd-ball paradigm while watching a silent movie. The experimental protocol included four sessions, specifically investigating the sentential (structural) versions of full (with the ‘to’ infinitival particle) and bare infinitival structures (without the particle) and the lexical (non-structure) versions of the verb either with or without the particle to determine whether the structure processing of sentences was a more crucial factor in the detection of the MMF than the simple processing of lexical items in verb-only conditions. The amplitude analysis of the resulting evoked fields showed that the presence of the syntactic category error of bare infinitival structures against syntactic predictions evoked a significantly larger MMF activation with a peak latency of approximately 200ms in the anterior superior temporal sulci in the left hemisphere, compared with the lexical items that did not have any syntactic status. These results clearly demonstrate that syntactically unexpected, illegal input in the bare infinitival structure is likely to be noticed more robustly in the brain while processing the structural information of the entire sentence than the corresponding verb-only items.