Abstract
The auditory and motor systems are strongly coupled, as is evident in the specifically tight motor synchronization that occurs in response to regularly occurring auditory cues compared with cues of other modalities. Timing of rhythmic action is known to rely on multiple neural centers including the cerebellum and the basal-ganglia which have access to both motor cortical and spinal circuitries. To date, however, there is little information on the motor mechanisms that operate during preparation and execution of rhythmic vs. non-rhythmic movements. We measured acceleration profile and muscle activity while subjects performed tapping movements in response to auditory cues. We found that when tapping at random intervals there was a higher variability of both acceleration profile and muscle activity during motor preparation compared to rhythmic tapping. However, the specific rhythmic context (cued, self-paced, or syncopation) did not affect the motor parameters of the executed taps. Finally, during entrainment we found a gradual as opposed to episodic change in low-level motor parameters (i.e., preparatory muscle activity) that was strongly correlated with changes in high-level parameters (i.e., shift in the reaction time to negative asynchrony). These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters that are related to its production. These changes in motor output were insensitive to the specifics of the rhythmic cue: although it took subjects different times to become entrained to different types of rhythmic cues, the motor actions produced once entrainment was obtained were indistinguishable. These findings suggest that motor entrainment involves not only adjusting the timing of movement but also modifying parameters related to its production. The reduced variability of muscle activity during the preparatory period could be one mechanism used by the motor system to enhance the accuracy of motor timing.
Highlights
The auditory and motor systems are tightly coupled via direct and indirect anatomical pathways
reaction time (RT) measured during rhythmic tapping, when cues were presented at fixed intervals, fell into two different subgroups (Figure 2B)
We showed that the auditory context substantially affects motor actions, as expressed in reduced variability in both acceleration and muscle activity when preparing for the ensuing tap, but not during the actual tap
Summary
The auditory and motor systems are tightly coupled via direct and indirect anatomical pathways. A common paradigm to study motor entrainment to rhythmic cues is finger tapping: a simple discontinuous rhythmic task through which auditory-motor coupling can be probed (Michon and van der Valk, 1967). In this task, motor synchronization to the auditory cue occurs very rapidly. Within 2–3 stimuli, subject tapping-times become predictive so that the tap occurs several tens of milliseconds before the auditory cue is delivered This property, which is often referred to as negative asynchrony (Aschersleben and Prinz, 1995; Miyake et al, 2004; Pollok et al, 2004), shows that the motor command is generated before the onset of the auditory stimulus through an anticipatory timing control (Thaut et al, 1999). While the perceptual aspects of this rhythmic entrainment have been studied extensively (Thaut, 2003; Repp, 2005), much less is known about concurrent changes in motor preparation and motor performance during entrainment and after negative asynchrony is achieved
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
