title: Transitions in neural oscillations reflect prediction errors generated in audiovisual speech.
abstract: According to the predictive coding theory, top-down predictions are conveyed by backward connections and prediction errors are propagated forward across the cortical hierarchy. Using MEG in humans, we show that violating multisensory predictions causes a fundamental and qualitative change in both the frequency and spatial distribution of cortical activity. When visual speech input correctly predicted auditory speech signals, a slow delta regime (3-4 Hz) developed in higher-order speech areas. In contrast, when auditory signals invalidated predictions inferred from vision, a low-beta (14-15 Hz) / high-gamma (60-80 Hz) coupling regime appeared locally in a multisensory area (area STS). This frequency shift in oscillatory responses scaled with the degree of audio-visual congruence and was accompanied by increased gamma activity in lower sensory regions. These findings are consistent with the notion that bottom-up prediction errors are communicated in predominantly high (gamma) frequency ranges, whereas top-down predictions are mediated by slower (beta) frequencies.
authors.affiliation: Inserm U960 - École Normale Supérieure, Paris, France.
authors.forename: Luc H
authors.initials: LH
authors.lastname: Arnal
authors.forename: Valentin
authors.initials: V
authors.lastname: Wyart
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Giraud
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways; D013060:Speech / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*