Biophysical Phantom Model

This is a phantom bursting model, (see Bertram et al, Biophys. J. 79:2880-2892, 2000 ) for pancreatic beta-cells in which the role of s_1 is played by cytosolic calcium (c) and the role of s_2 is played by ER calcium (cer) and the ADP/ATP ratio (a).

Reference: Bertram and Sherman, Bull. Math. Biol., 66:1313-1344 2004.

XPP files by figure:

Master file

Making Your Own Animations

The best way to see the animations is with XPP and its animator.


  1. XPP file


  2. Animation script file

With these files you can view the moving slow manifold and nullcline in the V-w (omega) plane. The file is set to produce slow bursting with the ER/ATP model. To see animation choose View/Toons and read in the animation file from the animator File menu. File/Get set can be used to visualize other burst modes. You will need to adjust the parameters ttotal, wmin, and wmax to get the right scaling.

Saved Animations (Animated GIF files)

Warning: Some of these files are large, so make sure you have enough free memory (256 - 512 MB recommended). I recommend downloading the image file to your machine and playing there (eg., in Netscape right-click)

What you will see: Each animation has the time course in purple in the upper half and the v-w phaseplane in the lower half. The slow manifold (where v and n are at steady state) is in black and the w nullcline is in blue. The trajectory is red.