Fig. 4: AP propagation relies on axonal morphology.
From: Membrane mechanics dictate axonal pearls-on-a-string morphology and function
a, Schematic showing the model setup. APs were modeled in real geometries using a generalized cable equation to calculate the spatial and temporal distribution of channel current, membrane voltage and gating variables. b, Voltage responses at 270 µm from cylindrical axons (left) and pearled axons (right) when NaVs are distributed either uniformly (dark color) or periodically (lighter color). Note that the distribution of NaVs only matters if axons are pearled. c, Plot of the relationship between AP velocity and the diameter of cylindrical axons. Dots are fitted with a simple linear regression curve. d–g, Plots of the relationship between AP velocity and the connector width (d), connector length (e), NSV width (f) and NSV length (g). Dots are fitted with a simple linear regression curve, except for f, which is fitted by a nonlinear Gaussian curve. h, Plot of predicted AP conduction velocity based on the dimensions of NSVs and connectors in neurons treated with sham (control) or 5 mM MβCD. i, Schematic of the electrophysiology recording setup. Schaffer collaterals were stimulated from the end of CA1 to measure the back-propagating AP in the CA1. j, Example traces from recordings in acute slices of mouse hippocampus treated with either sham (control) or 5 mM MβCD for 30 min. The solid vertical line marks the peak. k, Plot of AP conduction velocity from the experiments in j. Data were analyzed by Mann–Whitney U-test (two sided) and are shown as mean ± s.d.; N = 8 animals each, n = 14 slices for DMSO, and n = 12 slices for MβCD.
