Bursting in cerebellar stellate cells induced by pharmacological agents: Non-sequential spike adding
Fig 5
The effects of gHVA on the dynamics of the full system (1).
A) Bifurcation diagram of the full system (1) with respect to gHVA using the L2-norm of the state variables. The branch of equilibria (black) undergoes two Hopf bifurcations, labeled HB1 and HB2. The equilibria are unstable (dotted) between HB1 and HB2 and stable (solid) otherwise. The envelope of unstable periodic orbits (dotted dark green) emanating from HB1 undergoes a saddle-node bifurcation of periodic orbits (SNP) and terminates at a homoclinic bifurcation, denoted HC. The envelope of periodic orbits (dark olive) generated from HB2 is unstable, but becomes stable at a saddle-node bifurcation of periodic orbits (SNP) and terminates at a homoclinic bifurcation very close to the right of HB1 (not shown). The light olive line is the continuation of the dark olive line obtained by numerical integration of the full system (1). Both correspond to the envelope of pseudo-plateau BPOs (labeled PB). The ⊃-shaped curve (light green) is an isola of POs corresponding to tonic firing (labeled T); it consists of two branches separated by a saddle-node bifurcation of periodic orbits (SNP∞). The upper branch is stable and becomes unstable at a period-doubling bifurcation (PD). The set of (colorful) curves to the right of PD within the box shows a family of more isolas of square-wave BPOs (labeled SW) (for better visualization, see the magnification of this box in Fig 6A). B) Time course of a pseudo-plateau BPO for gHVA = 0.4 μS.cm−2.