The training set that was used for training the model was electrophysiological recordings taken during the 10–21 differentiation days, as the differences between the NR and LR neurons are largest at these times. The model was trained with features extracted from the recordings of five patients each time, and the classification was done on the sixth patient. This procedure was followed repeatedly for each of the six patients (training on the recordings of the other 5). The features that were used by the classifier were (1) the total number of spikes in 30 current injections, stating from 12 pA below the current needed to hold the cell at −60 mV; (2) the spike height; (3) the threshold potential for evoking an action potential; (4) the number of spikes in the first three current injection steps starting with the smallest current injection needed to produce one spike; (5) the number determined in the fourth feature normalized by the total number of spikes as in the first feature; (6) the number of spikes in the first three current injections as in the
