Neural correlates of resynchronization in a paced finger tapping task

JUAN KAMIENKOWSKI; LG CACERES; RODRIGO LAJE; MARIANA LUZ BAVASSI

San Diego

Congreso; Society for Neuroscience, 2018 Annual Meeting; 2018

Society for Neuroscience

Few animal species have the ability of sensorimotor synchronization (SMS), that is keeping pace with an external metronome as in finger tapping to a beat. SMS in humans is a spontaneous and very robust behavior, and it is the basis of music and dance. However, after many decades of research mostly focused in isochronous sequences, the search for neural correlates of the behavior has just begun, e.g. neural signatures of the asynchrony and the stimulus period, and a mechanistic explanation of the behavior in terms of neural processes and brain regions is still missing. The description of neural activity during resynchronization after a perturbation is even scarcer. Here we report an analysis of EEG recordings during a paced finger tapping experiment with tempo perturbations.Ten subjects, all right handed and with musical training, participated in the experiment comprising four sessions. Subjects had to perform a paced finger-tapping task with unexpected step-change perturbations of +10% and -10% of the stimulus period. We simultaneously recorded the tapping asynchronies (time difference between every response and the corresponding stimulus) and the EEG activity. The resulting epochs were arranged in three groups according to the tertiles of the asynchrony distribution at the moment of the perturbation. Our results suggest a novel frontal neural component that spans a few periods while the subject is resynchronizing and that distinguishes among the asynchrony groups. A second finding is that alterations to the time shape of a component of central origin resembling an N1-P2 complex also span several periods after the perturbation and depend on the direction of the perturbation (+10% vs -10%). In addition, a counterintuitive result is that the number of taps it takes to the subject to go back to synchrony after a perturbation only partially correlates with the asynchrony at the time of perturbation (i.e. how far from synchrony the subject is when the period changes). In summary, we take a step towards finding the neural correlates of resynchronization by showing EEG components that span several periods after a tempo perturbation and whose latencies and/or amplitudes do not correlate with either purely motor or sensory events. The time course of resynchronization at the behavioral level can be predicted by looking at the neural activity at fronto-central locations.