Excitability in the AHH model.

(A) traces following brief (0.1 ms) cathodal and (B) anodal stimulus pulses, for different values of . Threshold indicated in each panel. (C) Cathodal and anodal strength-duration curves for different values of . (D) Cathodal and anodal threshold (for 0.1 ms stimuli), rheobase, and chronaxie, as functions of . Current pulse amplitudes in (A): 64-66 (left); 633-635 (middle); 600, 800, 1000 (right); in (B): 198-200 (left); 397-399 (middle); 400, 600, 800 (right); in .