Effect of stimulus and feedback sensory modalities in paced finger tapping

The interaction between brain and body displays rich temporal and spatial dynamics. The temporal aspects of this interaction, unlike the spatial ones, are not yet very well understood, particularly with regard to how the brain processes temporal information at intermediate timescales, such as during synchronization with a periodic stimulus (i.e., sensorimotor synchronization, or SMS). Our experimental paradigm is the paced finger tapping task, where a participant is instructed to synchronize their finger’s movement with a periodic sequence of stimuli by tapping on a surface. Despite its apparent simplicity, this task involves numerous neural processes, such as temporal prediction (as the participant has to predict the next stimulus in order to achieve synchronization), temporal comparison/estimation (as the participant monitors their past performance in order to make corrections), and temporal production (as the participant must produce time intervals). SMS is a spontaneous phenomenon in humans and is quantified by the synchronization error, or asynchrony (that is, the time difference between each response and its corresponding stimulus in the sequence). There exist several conceptual models in the literature (e.g., Fraisse-Paillard and SAM) that attempt to explain the observed dependence of the mean asynchrony on the stimulus and feedback sensory modalities. In this work, we analyze the results of an experiment that casts doubt on these models’ predictions.