Fig. 2: Impact of a single mitochondrion on action potential conduction velocity.
A Schematic of the pathway between HVC and RA. Modified from50. B1 Longitudinal section of an axon bundle. B2 Histogram of measured mitochondrion lengths estimated from the major axis of an ellipse fit (n = 55 mitochondria). Bin size = 0.05 µm. C1 Schematic of the modeled 0.6 µm long section of an axon containing a mitochondrion. Amit, cross-sectional area taken up by a mitochondrion; Aax, area free from mitochondrion; L, mitochondrion length. C2 Equivalent circuit of the axial component used in our model. Rmit, resistivity of the mitochondrion; Rax, intracellular resistivity of the axon without the mitochondria. D Action potential conduction velocity decreases for cylinders containing a mitochondrion, as a function of cross-sectional mitochondrial occupancy of the axon for different axon diameters. The range of cross-section occupancies measured in our data is indicated with dashed lines. E Action potential latency increases for cylinders containing a mitochondrion, as a function of cross-sectional mitochondrial occupancy of the axon. The range of cross-sectional occupancies measured in our data is indicated with dashed lines. F1 Conduction velocity normalized to a mitochondria-free axon overlapped for all diameters. F2 Histogram of measured cross-sectional occupancies (n = 66 mitochondria). Bin size = 0.03. The corresponding range is marked with dashed lines on the graph above.
