The NEURON and XPP code is available for the paper:

Coggan JS, Ocker GK, Sejnowski TJ, Prescott SA (2011) Explaining pathological changes in axonal excitability through dynamical analysis of conductance-based models. J Neural Eng 8:065002

from the authors and at the authors web site:

as well as in this modeldb archive. The XPP code is the ode file in the top-level folder and the NEURON code is in the NEURONcode folder.

The XPP file was contributed by Steve Prescott and the NEURON code was contributed by Jay Coggan.