Beat perception and frequency tagging to study the neural dynamics of multisensory binding and sensorimotor synchronization

Beat is one of the most fascinating musical dimension. Feeling the beat in music refers to the spontaneous and universal ability to extract periodicities from stimuli that are not strictly periodic in reality. Through several models (synthesized in the “Dynamic attending” model, and later developed in the “Resonance theory for beat perception”), theorists have hypothesized that beat perception is subtended by an entrainment of neuronal populations at the frequency of the beat. This neuronal entrainment would allow the binding of distant cortical areas through synchrony of their activity. For example, neural activity from auditory and motor cortices, frequency-tuned to the beat, would subtend sensorimotor synchronization to the beat when listening to music. Similarly, binding by synchrony would constitute the mean by which activities from distinct sensory cortices integrate into a unique multisensory percept. In such, studying the neural mechanisms underlying beat perception constitutes a unique opportunity to study the neural dynamics of multisensory binding and sensorimotor synchronization in the human brain. 

Currently, we are developping a novel approach to study beat perception, based on the recording of SS-EPs, and the use of  ‘frequency tagging’ to track the cortical activity elicited by each of several concurrent streams of sensory input. Using these novel methods, we recently showed that musical beats induce a widespread neuronal entrainment that can be captured directly in the human EEG, in the form of an SS-EP appearing at the frequency of the beat (Figure 1). Furthermore, we showed that temporally-congruent auditory and visual beats, as compared to incongruent auditory and visual beats, elicit markedly enhanced SS-EPs, due to an increased phase coherence of their activities. Finally, we showed that moving to the beat is related to an enhanced synchronization of sensory- and movement-related SS-EPs. Taken together, these different studies indicate that the coherent integration of multisensory inputs having matching temporal dynamics, as well as the synchronization of movement to the temporal dynamic of a sensory stimulus is subtended by a « binding by synchrony » of the dynamic activity of distant cortical areas. 

Figure 1