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Matrix Flashes

Posted: 10 Feb 2004, 00:17
by M_Wentz
I have been working with Matrix data in Matlab and I need to know how we find when the flashes occurred and which rows and colums were flashing at a certain time.

P300 Speller Matrix data ...

Posted: 10 Feb 2004, 08:31
by gschalk

We have described the data format for the P3 speller matrix quite extensively for a recent BCI data competition. Please find it on ... sc_ii.html

I hope this helps. Let me know if you have more questions.


conversion problems

Posted: 16 Feb 2004, 22:45
by M_Wentz
Gerv, thanks for posting that answer, however, i am having trouble accessing the files such as stimluluscode and Flashing, and signal for that matter, so I think the problem is that the program we have, P300toASCII.exe is the wrong one, and it is not converting correctly, and that is why i cant find the signal or variables. When I worked on yes/no this summer the conversions worked corerctly at the lab, and my programs worked corerctly as well, so that why i think it could be that i have the wrong version of the conversion program.
let me know what you think, and please forward a different version if one exists as soon as possible, I'd like to get stuff up and running and am getting sooooo frustrated at these little glitches.

BCI2000 data conversion

Posted: 17 Feb 2004, 08:37
by gschalk

The program you should use is BCI2000toASCII. It comes with the BCI2000 installation package.


Finding when and which flash occurred with BCI2000/Matlab

Posted: 28 Feb 2004, 11:14
by Brendan

First, I would recommend you dowloand the EEGLab toolkit from This is a free Matlab package designed for viewing and manipulating EEG data. I have a few little scripts I wrote for this that could help. This toolkit makes it much easier to visualize when and where different things happen.

If you are using ASCII files and then importing them to Matlab, a flash begins whenever the "Flashing" column changes from 0 to 1. The type of flash can be determined from "StimulusCode."