Figure 3From: Synchrony of hand-foot coupled movements: is it attained by mutual feedback entrainment or by independent linkage of each limb to a common rhythm generator?Synchrony of separate or antidirectionally coupled hand and foot oscillations with the external clock. A. When the hand and the foot were moved either separately or antidirectionally coupled, the clk-mov delay remained constant (no significant effect of frequency) as the frequency increased from 0.4 to 1.8 Hz. Same representation and symbols as in Fig. 2. Constancy of the clk-mov was achieved despite the increasing lag of the hand and foot movements with respect to the EMG activation (mech curves, filled symbols in B), thanks to the progressive phase-advance of the motor activation with respect to the clock signal (neur curves, open symbols in B). All curves obtained during antidirectionally coupled hand-foot oscillations virtually overlap the corresponding curves obtained during separate oscillations of the two segments (green lines). Vertical bars in A and B = Standard Error of the Mean (covered by the symbol in most instances).Back to article page