EEG theta and gamma responses to semantic violations in online sentence processing.
We explore the nature of the oscillatory dynamics in the EEG of subjects reading sentences that contain a semantic violation. More specifically, we examine whether increases in theta ( approximately 3-7 Hz) and gamma (around 40 Hz) band power occur in response to sentences that were either semantically correct or contained a semantically incongruent word (semantic violation). ERP results indicated a classical N400 effect. A wavelet-based time-frequency analysis revealed a theta band power increase during an interval of 300-800 ms after critical word onset, at temporal electrodes bilaterally for both sentence conditions, and over midfrontal areas for the semantic violations only. In the gamma frequency band, a predominantly frontal power increase was observed during the processing of correct sentences. This effect was absent following semantic violations. These results provide a characterization of the oscillatory brain dynamics, and notably of both theta and gamma oscillations, that occur during language comprehension.
Hald
Lea A
LA
Max Planck Institute for Psycholinguistics, P.O. Box 310, 6500 AH Nijmegen, The Netherlands.
Bastiaansen
Marcel C M
MC
Hagoort
Peter
P
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D032882:Comprehension / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D011578:Psycholinguistics; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D012660:Semantics; D013826:Theta Rhythm