Mathematical Biosciences Institute

Signal Propagation Along Non-Uniform Axon
MBI Summer Project – 2003
  Group Leader:  Avner Friedman

Team members:  Stephen Clark, Yevgeniy Gokun, Hsiu-Tsun Hsieh,
Prasanna Karunanayaka, Namyong Lee, Mike Martin
Group Photo

In the summer of 2003, the Mathematical Biosciences Institute hosted their first educational summer program.  The theme of the program was on neuronal rythyms.  A select goup of faculty, graduate students, and undergraduate students took in very stimulating lectures on the requisite mathematics and the neurobiology that they model.  The mathematical and computer simulation lectures were delivered by David Terman and those on the neurosciences aptly given by Brian Smith.  Participants also had the opportunity to visit several research labs on the Ohio State University campus.  After a week of lectures, the participants were divided into four groups, each with a different project and focus.

This page is devoted to one of those groups whose study concerned signal propagation at abrupt changes in the diameter of an axon.  Avner Friedman, our group leader and MBI director, charged the group with investigating these properties both numerically and analytically.  We reviewed a great abundance of literature, realizing that a lot of work has been done in the area, but there are still many open questions.  Our simulations utilized the Fitzhugh-Nagumo, Morris-Lecar, and Hodgkin-Huxley models for action potentials along the length of an axon.  Using the first two of these models we observed signal transmission, signal blocking, signal reflection, and hybridizations of these phenomena.  Our work on the Hodgkin-Huxley system is ongoing as well as our pursuit of existence proofs for these phenomena.  Work in the area has potential applications for amyotrophic lateral sclerosis (ALS), diseased cardiac tissue, and mechanisms of "pain."

By creating and maintaining this page, we intend to share our work and resources with others, continue our work on the project (by giving pointers to our subsequent endeavors), provide an avenue for continued communications, and promote the important mission of the relatively young Mathematical Biosciences Institute.


Animated Numerical Simulation
– Transmission with Delay –

Continued Work and Additional Resources

  1. Original Powerpoint Presentation
    Presented at the MBI on 31 July 2003 – click here

  2. Fitzhugh-Nagumo ODE Simulation Tool
    on-line webMathematica web page  – click here

  3. Morris-Lecar ODE Simulation Tool 
    on-line webMathematica web page – click here

  4. Hodgkin-Huxley ODE Simulation Tool
    on-line webMathematica web page – click here

  5. Fitzhugh-Nagumo PDE Simulation Tool
    on-line webMathematica web page – click here

  6. Morris-Lecar PDE Simulation Tool
    on-line webMathematica web page – click here

  7. Hodgkin-Huxley PDE Simulation Tool
    on-line webMathematica web page – click here

  8. To Be Posted
    additional info

Links of Interest

Last updated: 15 October 2003
maintained by:  Mike Martin