Synchronization of periodic movements with external events and interlimb coordination: phase entrainment or phase resetting?

The aim of this study is to investigate of the synchronization of periodic rhythmic movements with single discrete movements as reaction to external trigger signals. The underlying coordination principle derived from the experimental results is supposed to be either phase entrainment or phase reset. In phase entrainment, the response is more probable to occur during the phase, when the periodic rhythm is in the same direction as the discrete movement, but less probable, when directions are opposite. When the rhythm of the periodic movement is disturbed by the discrete movement, two types of phase reset can be obtained: type 1 resets provoked at weak perturbations show a small phase shift on the ongoing rhythm, whereas type 0 resets occur at strong perturbations and cause large phase shifts.