Elena Cocherová 1,2; Jozef Púčik 1; Martin Nováček 1
Institute of Electronics and Photonics, FEI STU, Bratislava, Slovak Republic
1; Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovak Republic
Lékař a technika - Clinician and Technology No. 2, 2012, 42, 57-60
Conference YBERC 2012
The software package described in this article is dedicated for educational and research purposes in the area of electrophysiological cell membrane properties modeling. The designed and created software package offers a selection of several models of nerve fibre membrane, cortical neuron models and various models of heart cells. The model properties and simulation conditions can be set interactively. Consequently, generation of an action potential (AP) on a particular membrane can be observed. The software allows computation and graphical visualization of actual time courses of model state variables, particularly the membrane potential, membrane currents and other model variables. Eventually, additional important characteristics are evaluated from the output data, such as AP duration (APD) of heart cells or AP frequency of cortical neurons.
Computational cell models are a very useful tool for
better understanding of cell function, furthermore, they
create powerful ability to predict cell behavior under
different conditions. Models of excitable nerve, heart
and muscle cells have been developed for more than
half a century. This began with the well-known
Hodgkin-Huxley model of the giant squid axon , and
other cell type models then followed.
Various models of nerve fibre membrane , ,
, ,  cortical neuron models  –  and
various models of heart cells ,  –  are included
in this software package:
Nerve fibre membrane models:
Schwarz-Eikhof model, and more;
Cortical neuron models:
Wilson regular spiking model,
Wilson fast spiking model,
Wilson bursting model, and more;
Heart ventricular cell models:
Hund-Rudy dynamic model,
O'Hara-Rudy model, and more;
Other heart cell models include:
Michaels model of the sinoatrial (SA) node,
Nygren model of the atrial cell.
The cell type branch and consequently the cell model
type is selected in the main window of the designed
program (Fig. 2, Fig. 4). The following two main
parameters can then be set: (1) the number of periods
(period is denoting the cycle length) and (2) the
duration of one period.
A stimulation current of
prescribed amplitude and duration is applied to the
membrane during each period.
LÉKAŘ Parameters related to stimulation current, as well as
many other cell model parameters, such as intracellular
and extracellular ion concentrations, ion channel
characteristics and dimensional attributes can be
changed in the “Model parameters” window. In the
“Initial conditions” window, the user can view and
change the values for the initial conditions of model
After pressing the “Compute” button, new
computation is achieved with actual parameter settings.
Results are graphically visualized on three panels: the
upper panel shows the time course of the membrane
potential, the middle one (“Subplot2”) shows the time
course of the selected state variable, such as
intracellular calcium concentration (Fig. 4) and the
bottom one (“Subplot3”) shows the time course of
selected membrane current or a different selected
derived variable, as exemplified in the evaluated APD
also in Figure 4. After pressing the “More info” button,
a new window with a description of the particular cell
model is opened.
Nerve fibre membrane models
The Hodgkin-Huxley model of an unmyelinated
nerve fibre is one of the most often used models .
This model consists of only two types of voltagesensitive
ion channels: the sodium channel and the
potassium channel; which are represented by nonlinear
conductances GNa and GK (in mS) in Figure 1.
The stimulation current Ist (in μA) across the
membrane is divided into the ionic current Iionic
and capacitive current through the membrane
capacity Cm (in μF):
The time change of the membrane potential (in mV)
where iionic and ist are the current densities
(in μA/cm2), cm is the membrane capacity per 1 cm2
(in μF/cm2) and t is time (in ms). For the Hodgkin-
Huxley model, the ionic current density is determined
only by the sodium, potassium and leakage ion flows:
The cortical neurons generate a train of nerve
impulses with frequency of 1 – 100 Hz or a burst-like
activity of nerve impulses (Fig. 2, upper trace: bursts of
APs generated by the Wilson bursting model) . The
cortical neuron membrane usually contains more types
of ion channels than the nerve fibre membrane.
Using the developed software package, the influence
of stimulation parameters and model parameters on the
AP frequency may be observed (Fig. 2, lower trace).
Heart ventricular cells
The ventricular heart cells (myocytes) comprise
many more types of membrane ion channels, ion
pumps and exchangers, as depicted in Figure 3. These
include channels for the L-type calcium current, the
slow and rapid delayed rectifier potassium current, the
calcium pump current and the sodium/potassium
Calcium ions play the primary role in the excitationcontraction
coupling in myocytes. Advanced models of
left ventricular myocytes, such as the Hund-Rudy
dynamic model , and the O'Hara-Rudy dynamic
model  contain different calcium buffers, including
calmodulin and troponin, and also calcium ion fluxes
through the sarcolemmal (cell) membrane and through
the membrane of the sarcoplasmic reticulum (SR)
which is the main reservoir of calcium ions.
In the software package, membrane and SR currents,
ion concentrations and membrane potential parameters
influenced by model parameters and other simulated
conditions can be evaluated and observed. These
include the AP duration depicted in the lower trace in
The presented software package can help researchers
and students to understand the basic and more complex
principles related to excitation in neuronal and cardiac
cells. This knowledge poses the basis of the
electrophysiology of the heart and the nervous system.
The described software package has been developed
in the Matlab programming environment and it can be
continuously extended by new models of various cell
types. This software package can find a great number
of applications in different branches of
The work has been supported by the Slovak Ministry
of Education under grants VEGA 1/0987/12,
VEGA 2/0210/10 and APVV-0513-10.
Elena Cocherová, Ph.D.
Institute of Electronics and Photonics,
Faculty of Electrical Engineering and
Slovak University of Technology
Ilkovičova 3, 812 19 Bratislava
Phone: +421 2 60291174
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