NEUROFIT: Software for Fitting Hodgkin-Huxley Models to Voltage-clamp Data

Thumbnail Image
Willms, Allan R.
Journal Title
Journal ISSN
Volume Title

I introduce publicly available software for accurate fitting of Hodgkin-Huxley models to voltage-clamp data. I describe the model and nonlinear fitting procedure employed by the software and compare its results with the usual method of fitting such models using potassium \mbox{A-current} data from a pyloric dilator cell of the lobster {\em Panulirus} {\em interruptus} and sodium current data from an electrocyte cell of the electric fish {\em Sternopygus macrurus}. The set of parameter values for the model determined by this software yield current traces that are substantially closer to the observed data than those determined from the usual fitting method. This improvement is due to the fact that the software fits all of the parameters simultaneously utilizing all of the data rather than fitting steady-state and time constant parameters disjointly using peak currents and portions of the rising and falling phases. I analyze the convergence properties of the software's fitting algorithm using simulated data showing that accurate parameter values are obtained for most of the parameters using any reasonable initial values. The software also incorporates a linear pre-estimation procedure to help in determining reasonable initial values for the full nonlinear algorithm. I illustrate and discuss some of the inadequacies of voltage-clamp data.

Hodgkin-Huxley model fitting, Computer software, Voltage-clamp data, Inactivating current