Fig. 8

Entrainment ranges for the neural and derived phase models as a function of the forcing strength. Left panel illustrates entrainment ranges as a function of the forcing strength for weak intersegmental coupling corresponding to \(A_{a}=0.0004\), \(A_{d}=0.0002\), and \(\lambda_{a}=\lambda_{d}=4\). Right panel illustrates entrainment ranges for 100 times stronger intersegmental coupling with \(A_{a}=0.04\) and \(A_{d}=0.02\). Note that for weak coupling the entrainment ranges for the neural and derived phase models match closely while for strong coupling the entrainment ranges start to differ as the forcing strength increases. The dashed line on both plots represents Hopf bifurcations that occur when entrainment is lost. Smooth lines denote saddle-node bifurcations. The arrows in right panel correspond to the forcing strength values \(\alpha _{\mathrm{f}}\) where loss of entrainment is depicted in Figs. 10 and 11