Fig. 4. Coupling strength of rules 1 and 2 between contralateral legs. Likelihood of protraction in receiver legs of one side relative to time to of touch-down (t–t_trans10) in sender legs of the other side. Same plot details as in Fig. 3. (Top) Outer legs are sender legs, inner legs are receiver legs; (bottom) inner legs are sender legs, outer legs are receiver legs. For middle legs, likelihood values deviate little from the baseline, indicating complete lack of contralateral coupling. Coupling strength of rules 1 and 2 between intrasegmental front and hind legs is a lot weaker than for ipsilateral leg pairs. During curve walking the observed changes are in the same range as the shift of the baseline, indicating little or no context dependence.