Figure 8.

Field amplitude and extracellular resistivity effect on the propagation time delay and speed. a, Relationship between simulated action potential traveling delay time (from Row A to Row C) and endogenous field amplitude generated with various SF values in 4-AP/no Ca condition. For each d_c-c group, the time delay decreases linearly as field amplitude increases. b, Propagation speed increases with extracellular resistivity (R_ex; n = 3 for each R_ex with d_c-c = 2, 3, and 4 μm) but there is no significant differences among groups (p > 0.05 with one-way ANOVA). Within the physiologic range or R_ex (250∼380 Ωcm, Anatassiou et al., 2011), the speed ranges from ∼0.1 to ∼0.4 m/s. c, Endogenous field amplitude increases with R_ex (n = 3 for each value of R_ex with d_c-c = 2, 3, and 4 μm) but there is no significant differences among groups (p > 0.05 with one-way ANOVA). Within physiologic R_ex range, field amplitude ranges from ∼4 to ∼5 mV/mm.