HHsim is a graphical simulation of a section of excitable neuronal membrane using the Hodgkin-Huxley equations. It provides full access to the Hodgkin-Huxley parameters, membrane parameters, stimulus parameters, and ion concentrations. To learn about the Hodgkin-Huxley equations, see:

• Channeling with Bard, an online tutorial by G. Bard Ermentrout.
• Biophysics of Computation: Information Processing in Single Neurons, by Christof Koch. (See chapter 6.)
• Theoretical Neuroscience, by Peter Dayan and Larry F. Abbott. (See chapter 5.)
• A Simple Sodium - Potassium Gate Model, by James K. Peterson.

In contrast with NEURON or GENESIS, which are vastly more sophisticated research tools, HHsim is simple educational software designed specifically for graduate or undergraduate neurophysiology courses. The user interface can be mastered in a couple of minutes and provides many ways for the student to experiment.

HHsim is free software distributed under the GNU General Public License. The official HHsim web site is at https://www.cs.cmu.edu/~dst/HHsim. The online documentation, including sample screen shots, is available on this web site, and also included with the program when you download it. Also included are sample exercises that use the simulator.

Download HHsim Now

HHsim is available as a Windows or MacOS executable file that does not require a Matlab license. Source code is included. It is also available in source-only form; use that version on Linux. The latest release of HHsim is version 3.7, released in August 27, 2025.

---

Installation Instructions (version 3.6)

Windows:

1. Unzip hhsim_36_win.zip to a directory of your choice.
2. Run HHsim_36.exe, which is the HHsim installer. You must have Administrator rights on the machine in order to run the installer.
3. Ignore the "Connection" option and just keep pressing the "Next" button.
4. The installer will first install the MATLAB Runtime Component, allowing you to run standalone MATLAB applications. It will then install HHSim and leave an icon on your desktop.
5. You are now ready to use HHSim.

Linux:

• Please run HHsim from source. You will need to install MATLAB first.

Mac (Intel Architecture):

1. Unzip HHsim3_6_Mac.zip into the directory of your choice.
2. Use the MCR_Installer dmg to install the MATLAB Runtime Component, allowing you to run standalone MATLAB applications. NOTE: be sure to use the default location: /Applications/MATLAB/MATLAB_Component_Runtime/v76
3. Use the HHSim dmg to install HHsim.

---

Sample screen shot:

Click here for HHsim User's Guide

---

This work was supported in part by National Science Foundation grant DGE-9987588. Any opinions, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Dave Touretzky

Last modified: Mon Jul 31 17:29:49 EDT 2017