Problem using .eeg-files

Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Mon Mar 13 20:45:46 CET 2006

Hi Carina,

What kind of file is the *.eeg that you mention? Is it Neuroscan or
EEProbe? Both should be supported, however, today I did notice a bug
in code for neuroscan *.eeg files.

Regarding the configuration. The "xxx.ds" directory is special for
CTF MEG data, and contains a whole bunch of files (e.g. a seperate
header and data file, and other files containing the marker events).
If you want to run the tutorial, you should download the demo data
from teh ftp server.

In your case you should not make a xxx.ds directopry, but instead
   cfg.datafile = 'Ken_data.eeg'
   cfg.headerfile = 'Ken_data.eeg'
since the data and header information are both in the same file.
Furthermore, the
   cfg3.trialdef.includeTrigger = 3;
   cfg3.trialdef.excludeConditions = {'BAD'};
are also specific for CTF. You should read eth help of DEFINETRIAL,
specifically the
   cfg.trialdef.eventtype = '?'
will be of interest (since it shows you what you can actually use).


On 13 Mar 2006, at 0:53, Carina Graversen wrote:

> Hi. I just downloaded the Fieldtrip program to use it for my thesis
> as biomedical engineering, and I'm now trying to use it on a .eeg-
> file, which causes some problems for me. I have created the
> directory Ken_data.ds where I have the file Ken_data.eeg. I use the
> following configuration (taken from the tutorial and previous
> answers from this forum): cfg3 = []; cfg3.dataset = 'Ken_test.ds';
> cfg3.trialdef.includeTrigger = 3; cfg3.trialdef.excludeConditions =
> {'BAD'}; cfg3.blc = 'yes'; cfg3.blcwindow = [-0.2 0]; cfg3.lpfilter
> = 'yes'; cfg3.lpfreq = 35; cfg3.padding = 0; cfg3.datafile =
> 'Ken_test.eeg'; cfg3.headerfile = 'Ken_test.eeg'; =
> 'all'; I then call the preprocessing function: dataFIC =
> preprocessing(cfg3); Unfortunately I get the following errors:
> Warning: could not determine filetype of Ken_test.ds\Ken_test.meg4
> > In fieldtrip-20060306\private\filetype at 524 In definetrial at
> 109 In preprocessing at 270 evaluating trialfunction
> 'trialfun_ctf_epoched' ??? Error using ==> fieldtrip-20060306
> \private\read_ctf_meg4 could not open datafile Which I guess means
> that I haven't used the correct configuration, since the program is
> searching for a .meg4-file. I hope someone can help me by giving
> the correct configuration when working on .eeg-files :o). Thanks in
> advance. Regards, Carina Graversen Aalborg University, Denmark

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