Figure 2.

Strength–duration curves (A–C) and the respective electric charge thresholds (D–F) for unipolar cathodic pulses and bipolar pulses with the 2nd (anodic) phase 50% or 100% of the 1st (cathodic) phase. Electrodes were placed perpendicular to the nerve at a 5-mm distance to the cathode (A,D) or with the cathode touching the nerve (B,E). Panels (C,F) combine the thresholds measured at 5 mm (solid symbols) and those extrapolated from 0 mm to 5 mm (open symbols; see text for details). Dashed lines are data fits using the Lapicque formulation (A,D) or power function (B–F); solid lines just connect the mean values. Mean ± SE, n = 8–14 for most datapoints. Error bars may be not visible when they are smaller than the central symbol.