TEMPO-INDUCED TRANSITIONS IN POLYRHYTHMIC HAND MOVEMENTS

We investigate the cognitive control in polyrhythmic hand movements as a model paradigm for bimanual coordination. Using a symbolic coding o f the recorded time series, we demonstrate the existence of qualitativ e transitions induced by experimental manipulation of the tempo. A non linear model with delayed feedback control is proposed, which accounts for these dynamical transitions in terms of bifurcations resulting fr om variation of the external control parameter. Furthermore, it is sho wn that transitions can also be observed due to fluctuations in the ti ming control level. We conclude that the complexity of coordinated bim anual movements results from interactions between nonlinear control me chanisms with delayed feedback and stochastic timing components.