Eduardo Sontag's Hodgin-Huxley equations using JOde, for classroom use.

I is the applied current (for a more interesting problem, make it a function!)

Am, etc are the alphas; Bm, etc the betas

gm, etc are the conductances

Em, etc the reversal potentials

u is the voltage

C (capacitance) has been set to one

*Student Assignment:
*

- Try various integer values for the applied current, I = 1, 2, 3, ... so that you find the largest value I for which only one voltage spike is produced (don't forget to "Submit All" each time that you change the current, so the program runs again!). Print two pictures: one of the plot with this "I" that you found, and one of the plot with "I+1".
- As the current is set respectively to the values 10, 20, 30, 40, 50, 60, the amplitude of the spikes remains roughly constant, but the number of spikes changes ("frequency modulation"); report how many spikes you see for each of these 6 values (in the window from t=0 to t=100).
- Bring the value of "I" again to the original 15.1 Now display only "n" and "h" (click on them and un-select "u"). Observe that n(t)+h(t) add up to a constant; report what is the value (approximately) of that constant. Explain how this relates to something discussed in the notes (someone observed something that allows a nice reduction to a 2D system... who was that?) Important: to see the scales of n and h (not u), you need to change the "u" to "m" or "h" in the upper right button.)
- Now display also "m", besides n and h. Note that "m" changes a bit faster than n and h, at least during some intervals. (To see the color of "m" as black, you may change the "u" to "m" in the upper right button.)
- Provide printouts for all of the above. (If you have problems printing, see printing help. If all fails, do a "print screen"; most computers allow you to do that.)

*View (General)
Instructions on using the JOde Applet*

JOde was written by Marek Rychlik (rychlik@u.arizona.edu)

*Author's Home Page:* http://alamos.math.arizona.edu