Matlab EEG Toolbox

Download

SourceForge Logo
Please visit the sourceforge development and release service (see http://sourceforge.net/projects/eeg/). This provides a CVS repository and release versions. Please subscribe to the email list for users (eeg-users). If you would like to contribute to development of the toolbox, please subscribe to the developers email list (eeg-developers). Then follow the sourceforge instructions to register and to setup your ssh/cvs access to the toolbox source code. The ssh/cvs setup and development process is made easy by reading the introduction materials at http://sfsetup.sourceforge.net

Installation

The EEG toolbox download is a .tar.gz or .rar file, which can be extracted on windows, linux, unix platforms with rar software. On a unix/linux system, you might use the following command:

tar -zxvf eeg_toolbox_v1.5.tar.gz

Extract it to a folder on your matlab path or use the 'addpath [eeg_toolbox folder] -end' command to append a new folder to your matlab path.

Getting Started

See the documentation.

Full html documentation for eeg_toolbox.

There are now available some elementary functions for Analyze files. See the full html documentation for mri_toolbox.

The full html documentation provides html access to the information otherwise availabe using 'help [command]', once the toolbox is installed under matlab. In addition, it provides clear dependency links between functions in the toolbox.

Releases

There are now several releases of the toolbox available. See the release notes for a history of the development, if your curious. The latest release incorporates all previous releases.

Features

Please note this is not a signal processing toolbox. At present, there are no specific functions for processing raw EEG, such as filtering, averaging, etc. There are some functions in development for reading Neuroscan .CNT files, if you need these, please send email to the eeg-users email list. For examples of signal processing tools, please see the links below. This toolbox,at present, is useful for visualisation and measurement of ERP data and some MRI data.

The toolbox has been developed to facilitate quick and easy import, visualisation and measurement for ERP data. The toolbox can open and visualise ERP averaged data (Neuroscan, ascii formats), 2D/3D electrode coordinates and 3D cerebral tissue tesselations (meshes). All the features can be explored quickly and easily using the example data provided in the toolbox. The GUI interface is simple and intuitive. The following lists the features already available and some items that could be developed.

There are now elementary functions to load and visualize MRI volumes in Analyze format (or the Freesurfer COR- format). It is expected these functions, together with mesh functions, will provide the opportunity to visualize mesh overlays with MRI volumes. It is also hoped that this will create an avenue for conversion of MRI volumes into BrainStorm format. For MRI processing, see the matlab image processing toolbox, the SPM toolbox for matlab, and the FSL tools (in c/c++ with source code available).

ERP Visualisation

Data Import/Export

Topographic Mapping

If the electrode position data is available or created from the standardized electrode positions available, the toolbox can generate topographic maps. There are various topography options, including 2D/3D surface mapping with various controls for contour mapping, scaling, and colour maps. If a scalp tesselation is available, the toolbox can load and visualise the 'mesh' and interpolating from the electrodes onto the mesh (only when they are already coregistered - the functions for coregistration are in early stages of development).

The following graphic illustrates a recent addition to topographic mapping (interpolating from 124 electrode sites onto a scalp mesh). As of May 2002, the methods are integrated with the GUI interface (they are available in the mesh_laplacian.m and mesh_laplacian_interp.m functions). Many thanks to Robert Oostenveld for critical assistance in development and testing of these functions.
scalp interpolation

Data Transforms/Analysis

Batch Processing

Feature Wish List

Recently Done

In Development

System Requirements - Development Platform

The distribution of this toolbox is in its infancy. It is not clear what the system requirements are. Obviously a matlab installation is required. I understand from one report that the toolbox GUI does not work under matlab 5.x, but that is one report only. For most ERP plotting, the toolbox creates about 4-8Mb of data in the workspace and GUI. For more elaborate mesh plotting and interpolation, the toolbox can create up to 40Mb of workspace data (probably that much again in the GUI itself).

The toolbox has been developed on matlab 6.0 (R12) with a win98 system (PIII 733 MHz, 512Mb PC133 SDRAM, GeForce 32Mb graphics card). I have noticed some problems with mesh plotting and interpolation on systems with less powerful graphics.

GUI Layout Problems?

There is no guarantee that GUI interfaces will appear correctly on different matlab platforms. It is developed on windows98, matlab6.0 (R12), but some of the text and boxes may not scale correctly on other systems. The toolbox uses normalized scaling for all GUI widgets, which should display and resize OK on any platform, but the matlab handlers seem to work differently with different display systems (X, windows, etc). Please just try resizing the GUI window until it looks OK for you.

If you find the toolbox useful and wish to modify the GUI, please have a look at the gui*.m files to adjust the size of widgets, figures or whatever. If you do tidy up the code for your system, please email your modifications to me with an indication of what is modified for what system. If you have the time and inclination, please register as a sourceforge developer and make arrangements to integrate your development efforts with the cvs repository.

Licence

This toolbox is released under the GNU General Public Licence (GPL, see http://www.gnu.org/licenses/gpl.html). The toolbox is provided with no implied or express warranties. Please use and distribute/develop the toolbox in accordance with the GPL, entirely at your own risk.

Script and function names are intended to be loosely descriptive of their purpose. Most of these scripts and functions have been developed and tested on limited dataset specifications, please be careful to verify operations on your data. Some of these scripts are under development and will not work at all. I have done a reasonable job to ensure that all the GUI bells and whistles actually work OK, but some of the stand-alone scripts are another matter. It is best if you have some familiarity with programming in matlab so that you can modify some script variables, which are most likely defined for use with my data and there are currently no user prompts to define these variables at runtime. Most, if not all scripts, declare relevant variables at the outset.

Other EEG/ERP matlab links

Some MRI links