Nullclines (left) and time course trajectories (right) of the 2 variable system for various values of kappa in the u-v plane. The values of kappa were chosen to give similar results to figure 4 in the original publication, but as the exact values used are not known, they only show approximately the same results. The right graph shows time courses trajectories (200 time units) for the various values of kappa, and the u-nullcline (orange). the high and low values of kappa (kappa = 0.13, blue and kappa = 0.0075, green)lead to stable steady states, the intermediate one (kappa=0.018, yellow) approaches a limit cycle.

The results were calculated and plotted using XPPaut and the Biomodels.net sbml2xpp converter.