This applet shows the voltage produce by a cell using the FHN model as
function of time after it is stimulated above its threshold.
The start button initiates the simulation and the reset button brings back
the parameters to the initial values.
The model parameters can be changed and observe the different dynamics
by clicking
For example by changing delta to 0.03 or bigger one can change the system
from excitable to auto-oscillatory.
By increasing epsilon the APD decreases and vise versa ( try 0.05 and 0.001).
The FHN model can be found in: Biophys. J. Vol 1 445-466, 1961 by R. FitzHugh
see also for example Physica D Vol 41 p173 1990, by M. Courtemanche and W. Skaggs and A.T. Winfree