Figure 4. The kinetics of Na⁺ and K⁺ channels are heavily dependent on temperature change in the model neuron.

A–C. The maximal value of Na⁺ activation time constant τ_m (A) and Na⁺ inactivation time constant τ_h (B), and K⁺ activation time constant τ_n (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⁺ activation variable m (D), Na⁺ inactivation variable h (E) and K⁺ activation variable n (F) for temperature T = 18°C, and 36°C, respectively. Note that at 36°C, the peak inactivation of the Na⁺ current is considerably more complete (e.g. attains a lower value) (E) and the K⁺ activation during the rising phase of the action potential is significantly less (F) than at 18°C.