Figure 5.

Comparison of AP Waveforms in Mutant and Control

(A and B) Average phase plots, $\left(\frac{d\left(\Delta F/F\right)}{dt}\text{vs}\Delta F/F\right)$, from steps with nine action potentials, for (A) control and (B) SOD1 A4V cell lines. The first two spikes are highlighted in blue, after which the cells converged to a stable limit cycle.

(C and D) Average AP waveforms from all stimuli, which produced (C) two and (D) nine APs during a single stimulus epoch. APs from stimuli during which the cell entered depolarization block were excluded. Spikes were aligned in time by their peak and in $\Delta F/F$ by their pre-peak minimum. Average waveforms from stimulus epochs with different numbers of APs are quantified in Table S2.