Fig. 6.
Effects of different integration methods on accuracy for Markov models of ionic conductances. All traces are from a pure computer model, testing different time steps for model integration. The different time steps are distinguished by the durations of the horizontal steps (1, 10, 20, and 50 μs). The Markov model was the 12-state sodium channel model of Kuo and Bean (1994). Top trace: voltage step for the model. Bottom traces: 4th-order Runge-Kutta (RK4; black), exponential Euler (red), and implicit Euler (blue). The implicit Euler had better stability than Runge-Kutta for time steps >10 μs (asterisk) and better accuracy than exponential Euler for time steps as large as 50 μs. PO, open probability.