Noble Model
for one cell

This model is used to simulate the activation of Purkinje fiber cells using the model of Noble. Purkinje cells are auto-oscillatory, so there is no need to use a stimulus to produce an action potential. However, they nonetheless respond to stimulation that occurs before they would self-excite.

To use the applet, click the Start button to initiate the simulation and the Reset button to return the parameters to their initial values. Check the box for each variable to plot it in the window. The final action potential duration (APD) and diastolic interval (DI) are calculated automatically. Press the Plot Currents button to view the individual transmembrane currents.

S1 and S2 indicate the timing of the first and second stimuli, respectively.

Things to try:

  • Uncheck the Voltage box and check the boxes for some of the other variables.
  • Change the timing of the second stimulus to determine the earliest possible time after the first stimulus when an action potential can be generated.
  • Changing parameter values to alter the dynamics from auto-oscillatory to purely excitable. For example, change gNa2 from 0.14 to 0.12. Then try setting S1 to 10 ms and S2 to 400 ms, 500 ms, or other values.

    Noble D. (1962) J Physiol 160, 317-352.