Effect of ATP on the rate constant. (A and B) Effect of ATP on 2πc in linear plot (A), and semi-log plot (B). Average and SEM are shown for n = 7 (Neb⁺ fibers) and n = 9 (Neb⁻ fibers). Continuous lines represent best fit curves to Eq. 3. c is the characteristic frequency of the fast exponential advance, and 2πc is its rate constant as defined in Eq. 1.