Fig. 13

Impact of \(ca_{i}\) on \((v, h)\) system. Impact of \(ca_{i}\) on the nullclines and fixed points of the \((v, h)\) system. (A) v-nullcline (red) and h-nullcline (cyan) of the layer system (8a)–(8b) intersect at a single stable fixed point denoted by the circle. (B) Increasing \(ca_{i}\) moves the v-nullcline to the upper left and eventually induces a cusp bifurcation but a unique fixed point remains for all \(ca_{i}\). A solution trajectory of (7a)–(7e) projected into \((v,h)\)-space (black) stays near the stable fixed point location for a transient period and then jumps away