Trajectory Formation in Timed Repetitive Movements

In skills as diverse as piano playing or swinging a racquet in tennis, movements comprise a pattern that involves going to and away from the target, anecdotally referred to as attack and release. Although all such voluntary actions involve timing, timed repetitive movements involve bringing an end effector periodically to a certain location in the workspace, in relation to a sensorimotor event. Research in this area has involved the characterization of synchronization errors, identification of sources of variability in synchronization, and determination of neural structures involved in organizing such behavior. While much is known about the timing errors made while synchronizing with respect to external beat, not much is understood about what kind of movement trajectories are needed for timing accuracy. In this chapter, I review some recent work that links the ideas from the trajectory formation literature to what we currently know about timing accuracy in repetitive movements. Additionally, I present a paradigm that offers to bring together the dynamical systems approach with the information processing accounts of movement timing.