Purvis LK, Smith JC, Koizumi H, Butera RJ (2007) Intrinsic bursters increase the robustness of rhythm generation in an excitatory network. J Neurophysiol 97:1515-26 [PubMed]

are available at the cellml.org website:

Figure 2A

https://models.cellml.org/exposure/baa78a664bd1f620acce7257883fc91a/purvis_smith_koizumi_butera_2007_npc.cellml/view

Figure 2B

https://models.cellml.org/exposure/baa78a664bd1f620acce7257883fc91a/purvis_smith_koizumi_butera_2007.cellml/view

Example: Open the model files in opencor. Change the ending point to 20000ms and Point interval to 0.1. To graph each model right-click Vm in membrane list (select Plot against integration variable). Finaly run each (click upper left play triangle) creates the following graphs similar to fig 2AB although the second current step from 0.2 to 0.8 is absent in the model