Proactive inhibition enhances sensorimotor synchronisation

Sensorimotor synchronization (SMS) is the coordination of movement with an external rhythm. The idea that SMS tasks require proactive inhibition comes from a robust phenomenon observed in these studies; when tapping in time to a beat humans tend to make their responses about 20 to 80 ms prior to the beat [referred to negative mean asynchrony (NMA)]. Interestingly, trained musicians
generally have less NMA than novices. How might this reduction in NMA be achieved? One clue comes from experiments that have used explicit performance feedback to train non-musician subjects to tap closer to the beat. In such studies subjects have been shown to be able to significantly reduce their NMA by learning to “hold themselves back” in order to delay the tap. Such self-reports suggest that in order to tap closer to a beat (as musicians do) one must learn to
overcome a natural tendency (i.e. prepotent response) to anticipate the beat.
To test this idea we developed a new task that combined the SST and the tapping task thereby measuring synchronisation whilst also manipulating proactive inhibition and tested two effector systems: manual and vocal. Manual responding in an irrelevant stop condition was significantly ahead of the beat whereas vocal responding was not. In the relevant stop condition we found that
manual responding, but not vocal responding, was significantly delayed compared to RTs in the irrelevant stop condition. These results support the interpretation that proactive inhibition increases sensorimotor synchronisation in a finger tapping task.