Fig. 4

Basic structures of subsystems for the Jasinski model. Basic structures of subsystems for the Jasinski model (5a)–(5g). (A) Projection onto \(({na_{i}}, v)\)-space of the bifurcation diagram for the fast subsystem of the voltage compartment with \(na_{i}\) as a bifurcation parameter, along with the \(na_{i}\)-nullcline shown in cyan. The black curve represents the critical manifold S of the fast subsystem (solid for stable fixed points, dashed for unstable), and the blue curve shows the maximum of v along the family of periodics P. (B) Nullsurfaces of \(ca_{i}\) for the calcium compartment with v at its minimum (upper surface) and maximum (lower surface), in \((ca_{i}, c_{\mathrm{tot}}, l)\)-space. The black curve denotes the SB solution trajectory of the nondimensionalized Jasinski model. The right branches of these two nullsurfaces lie close to each other. (C) A zoomed-in and enlarged view of (B)