Afferent fiber membrane input resistance and EPSP decay kinetics. A, In current clamp, afferent fibers were hyperpolarized by injection of negative currents from −50 to −150 pA for 100 ms. Averages of membrane potential responses from one afferent fiber at 22°C and 31°C are shown in black and red, respectively. Red and black arrows indicate the absolute change in membrane potentials at 22°C and 31°C, respectively. Input resistance of an afferent fiber was calculated following Ohm's law, R_in = ΔV/ΔI. The decay phase of the membrane potential was fit by a double exponential function (gray dashed lines). B, τ_decay of EPSPs was plotted against R_in of the respective fibers. Each pair of data points recorded from the same afferent fiber is connected with a dashed line: room (black) and high (red) temperature (n = 5). A linear regression fit is shown in blue and indicates a positive correlation between EPSP τ_decay and R_in (slope = 0.018 ± 0.003, R² = 0.79, p = 0.0006).