Exploring Neuronal Bistability at the Depolarization Block
Figure 5
Two-parameter bifurcation diagrams of the DA neuron and the HH neuron in vnh/vhh/vmh and Iapp planes.
The hysteresis regions are shaded gray. A) Hysteresis is strong in the DA neuron. Parameters are from Table 1. B) Hysteresis is removed and the oscillatory region expands in the DA neuron with the increase in the half-inactivation of the Na+ current. Parameters are from Figure 4B. C) Hysteresis is not reduced with the decrease in the half-activation of the Na+ current. Parameters are from Figure 4B. D) Hysteresis is weak in the HH neuron. Parameters are from Table 1. E) Hysteresis is removed in the HH neuron with an increase of vhh. Parameters are from Figure 4D. F) Hysteresis is weak in the HH neuron with an increase of vmh. Parameters are from Figure 4D. A solid curve represents an Andronov-Hopf bifurcation, a dashed curve – a saddle-node bifurcation of limit cycles. Horizontal dotted lines in A) and D) represent the values of half-activation of the K+ current taken in B), C) and E), F), correspondingly. Horizontal dotted lines in B), C) and E), F) represent the values of half-(in)activations from Table 1 for the DA and HH neurons, correspondingly.