Musical Training and Perceptual History Shape Alpha Dynamics in Audiovisual Speech Integration

Introduction: Speech perception relies on integrating auditory and visual information, shaped by both perceptual and cognitive factors. Musical training has been shown to affect multisensory processing, whereas cognitive processes, such as recalibration derived from a perceptual history, influence neural responses to upcoming sensory inputs. To investigate these influences, we evaluated cortical activity associated with the McGurk illusion focusing specifically on how musical training and perceptual history affect multisensory speech perception. Methods: Musicians and age-matched nonmusicians participated in electroencephalogram experiments using a McGurk task. We analyzed five conditions on the basis of stimulus type and participants’ responses and quantified the rate of illusory percepts and cortical alpha power between groups using dynamic imaging of coherent sources. Results: No differences in McGurk susceptibility were detected between musicians and nonmusicians. Source-localized alpha, however, revealed group-specific patterns: musical training was associated with frontal alpha modulation during integration, a finding consistent with enhanced top-down control, whereas nonmusicians relied more on sensory-driven processing. Additionally, illusory responses occurred in auditory-only trials. Follow-up analyses revealed no significant alpha modulation clusters in musicians, but temporal alpha modulations in nonmusicians depending on preceding audiovisual congruency. Conclusions: These findings suggest that musical training may influence the neural mechanisms of audiovisual integration during speech perception. Specifically, musicians appear to employ enhanced top-down control involving frontal regions, whereas nonmusicians rely more on sensory-driven processing mediated by parietal and temporal regions. Furthermore, perceptual recalibration may be more prominent in nonmusicians, whereas musicians appear to focus more on current sensory input, reducing their reliance on perceptual history.