Test data and model predictions. (A and B) Whole-cell currents were simulated stochastically with the test model in Fig. 2 A, using a standard activation/inactivation protocol. The data were processed to extract the time course of activation/inactivation (black traces in A) and the steady-state activation and availability curves (black symbols in B). The time course and steady-state curves were fitted together (see Fig. 4). The predictions of the model at the beginning and at the end of optimization are shown by the blue and red traces, respectively. The fit curves correspond to run I in Fig. 2 B, but all runs resulted in virtually identical fits. The true, initial, and estimated parameters and properties of the model are shown in Table 1.