Ion channel and current fluctuations underlie waveform variability.

<p>Ion channel and current fluctuations in an AP travelling along 0.2 µm diameter axons. All traces are aligned at the instant when the rising AP crosses half-peak. Data from the squid giant axon model is on the left, while the right plots show data from the rat hippocampal interneuron model. Shaded areas in A–D are the 3×SD envelope around the mean curve (dark curve). Light curves in A–D represent a sample of individual traces. (A) Membrane potential waveforms (B) Number of open Na⁺ (red) and K⁺ (blue) channels (C) Current flowing through Na+ (red) and K⁺ (blue) channels (D) Net membrane current (sum of Na⁺, K⁺ and leak) (E) SD of Na⁺ (red), K⁺ (blue) and net membrane (green) currents.