Figure 1
From: Bifurcation structure of adaptation versus depolarization block
Spike Failure via Adaptation. (A) Time course of the membrane potential (top) and slow Na+ channel inactivation, middle), during spike failure after a depolarizing current step (bottom). (B) Phase plane for fast/slow analysis. The N shaped voltage nullcline (black curve) is calculated at a constant value of slow channel inactivation corresponding to spike failure (dashed line in panel (A)). The middle branch is the effective spike threshold. The red trajectory corresponding to the red waveform in the left two traces exceeds this threshold but not the blue one.