Figure 5

V -nullclines (green), the three-branched c -nullcline (orange), and singularities for g _BK = 0.4 nS and different values of g _K (units in nS). Filled circles represent stable singularities and unfilled circles represent unstable singularities. Red circles (filled or unfilled) are ordinary singularities. Filled and unfilled circles in blue are folded nodes and folded saddles, respectively. Filled circles in cyan are folded foci. The points TR1 and TR2 are transcritical bifurcations (type II folded saddle-node bifurcations) and SN1 and SN2 are standard saddle-node bifurcations (type I folded saddle-node bifurcations).