<p>A–C. The maximal value of Na<sup>+</sup> activation time constant τ<sub>m</sub> (A) and Na<sup>+</sup> inactivation time constant τ<sub>h</sub> (B), and K<sup>+</sup> activation time constant τ<sub>n</sub> (C) as a function of temperature. Inset: Time constants of the variables as a function of membrane potential for temperature T = 18°C, 36°C and 42°C, respectively. D–F. Phase plots of membrane potential V vs. Na<sup>+</sup> activation variable m (D), Na<sup>+</sup> inactivation variable h (E) and K<sup>+</sup> activation variable n (F) for temperature T = 18°C, and 36°C, respectively. Note that at 36°C, the peak inactivation of the Na<sup>+</sup> current is considerably more complete (e.g. attains a lower value) (E) and the K<sup>+</sup> activation during the rising phase of the action potential is significantly less (F) than at 18°C.</p