Figure 10: Normalised objective surface reproduced by the RMS error between model and experimental APs, against two optimised parameters and representing reversal potential and maximum membrane conductance . Upper plot, 2D objective surface of multi-dataset based optimisation. Note the “noisy” local area indicated by the red arrow. The global minimum is labelled by the black arrow. Lower plot, 2D objective surface of single-dataset based optimisation. Inset: Zoomed 1D local objective surface near global minimum. When optimising the model to fit multiple datasets simultaneously, the number of local minima will be increased. However, each local minimum will be shallower compared to those of the single-dataset based surface.