Effects of sensory modality and tempo of stimuli on behavior and cerebral activities during rhythmic production and perception

Sensorimotor synchronization (SMS) is a natural human behavior associated with the perception of predictable, isochronous and environmental rhythmic stimuli. The main objective of this study is to test the conditions that improve the behavioral stability and accuracy of rhythmic SMS. We tested the interaction between different sensory modalities and tempos on the behavior and cerebral activities related to the production and perception of rhythmic stimuli. To this aim, participants were required to produce a SMS and continuation task (production task) and a perception task with 4 modalities (unimodal auditory stimuli, unimodal visual stimuli, bimodal audio-visual congruent – presented simultaneously – or bimodal audio-visual incongruent – presented non-simultaneously – rhythmic stimuli) and 3 different tempos (500 ms, 700 ms and 900 ms). Firstly, both auditory and congruent audiovisual modalities led to more stable SMS compared to the visual modality. Compared to the SMS with incongruent audiovisual modality, SMS with the congruent audiovisual modality led to higher EEG spectral power in the α frequency band over the superior parietal cortex, suggesting lower involvement of attentional/cognitive processes. Secondly, compared to 500 ms, the 900 ms tempo led to the most stable SMS and higher EEG spectral power relative to sensorimotor and attentional/cognitive processes during both SMS and perception. Thirdly, the SMS was the least stable for the 500 ms tempo and for the visual modality. Our results highlight higher stability of SMS and/or lower involvement of sensorimotor and attentional processes for the slowest required tempo (here, 900 ms) and for congruent audio-visual stimuli, suggesting that these conditions are optimal for rhythmic production. These findings provide new cues to understanding the effects of rhythmic-based interventions, especially in the context of sports training and rehabilitation programs.