Figure 8.
Activation thresholds for axons in 3D FEMs of nerves and cuff electrodes across different values of endoneurial resistivity (see illustration of methods in Figure 2). The default resistivities (red asterisks) were 12 Ω-m for ρendo-transverse and 1.75 Ω-m for ρendo-long. In the last column, the ratio of the transverse resistivity to the longitudinal resistivity was constant at 12 Ω-m/1.75 Ω-m = 6.9. All simulations used 2 μm axons and ρperi = 1149 Ω-m (DC, 37°C). First and second rows: Thresholds for the nerve model with two fascicles for different cuff electrode geometries. Third row: Thresholds for the nerve model with 10 fascicles and the bipolar circumneural cuff geometry. Data with four axon locations per fascicle – with the addition of thresholds for 2 and 10 μm axons placed in all fascicles of the multifascicular model – are provided in Supplement F.