Auditory stimuli extend the temporal window of visual integration by modulating alpha-band oscillations

Abstract

AbstractIn the multisensory environment, the interactions between inputs from different sensory modalities are not fully understood. Here, we conducted an electroencephalography (EEG) experiment to investigate how auditory stimuli shape the temporal window of visual integration in human subjects. Participants were presented with two consecutive visual flashes, either accompanied by an auditory beep or without, and were asked to report their perception of one or two flashes. Behaviorally, we found that the introduction of auditory input induced a longer temporal window for integration. Alpha frequency analysis further revealed that the presence of auditory stimuli led to poststimulus alpha frequency degradation, positively correlating with the prolonged temporal window, supporting the idea that alpha oscillations represent the temporal window of visual integration. Further exploration of prestimulus alpha oscillations revealed that auditory stimuli diminished the predictive role of prestimulus alpha frequency while enhancing the predictive role of prestimulus alpha phase in determining perceptual outcomes. To unveil the underlying mechanism, we developed a computational model based on the phase-resetting hypothesis and the perceptual cycle theory, successfully replicating key behavioral and neural findings. Together, our results suggest that concurrent auditory input extends the temporal window of visual integration by resetting the phase of alpha oscillations in the visual cortex, leading to alpha frequency degradation.Significance StatementTo reduce the complexity of our world, visual perception operates within temporal windows, where stimuli falling within the same temporal window become integrated, as evidenced by alpha-band oscillations. However, it is unclear how these temporal windows can be changed, especially when dealing with multiple senses simultaneously. This EEG study reveals that introducing auditory input prolongs the temporal window of visual integration by reducing alpha frequency. A computational model proposes auditory input-induced phase resetting as the underlying mechanism, influencing the predictive roles of alpha phase and frequency in perception. These findings offer a novel perspective on multisensory processing, providing new insights into the different roles of alpha frequency and phase in shaping temporal perception.