Voltage traces showing output of a simple single-compartmental model of a rhythm generating neuron in the pre-Bötzinger complex . A. Reference traces used to fit the model to. B. A trace showing the output generated by increasing the persistent sodium current conductance by only 20% compared to the original data. C. Result obtained after automatic parameter fitting using Evolutionary Strategies D. Result found by a Mesh Adaptive Search that started with the best result obtained using Evolutionary Strategies.