Interactive Modeling

Physical System

Giant axon from Loligo pealei
Image from http://www.mbl.edu

Conceptual Model

Hodgkin-Huxley cable equations

Simulation

Computational implementation of the conceptual model

	create axon
	axon {
		nseg = 43
		diam = 100
		L = 20000
		insert hh
	}
Use the CellBuild tool to create the model.
Save the model in hhaxon.ses using NEURONMainMenu/File/savesession.

Using the computational model

If starting from a fresh launch of nrngui, you can load the saved ses file from NEURONMainMenu/File/loadsession.

Alternatively one can use NEURON to execute interactive_modeling/hhaxon.ses

Linux/OS X terminal
cd interactive_modeling
nrngui hhaxon.ses
OS X GUI
drag and drop hhaxon.ses onto nrngui icon
MSWin
double click on hhaxon.ses

Exercises

1) Stimulate with current pulse and see a propagated action potential.

The basic tools you'll need from the NEURON Main Menu :
Tools / Point Processes / Manager / Point Manager to specify stimulation
Graph / Voltage axis and Graph / Shape plot to create graphs of v vs t and v vs x.
Tools / RunControl to run the simulation
Tools / Movie Run to see a smooth evolution of the space plot in time.

2) Change excitability by adjusting sodium channel density.

Tool needed:
Tools / Distributed Mechanisms / Viewers / Shape Name

3) Use two current electrodes to stimulate both ends at the same time.

4) Up to this point, the model has used a very fine spatial grid calculated from the Cell Builder's d_lambda rule.
Change nseg to 15 and see what happens.

Help reference


NEURON hands-on course
Copyright © 1998-2012 by N.T. Carnevale and M.L. Hines, all rights reserved.