No Events from mne_brain_vision2fiff

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1

Hello,

We are trying to convert brain vision EEG files using mne_brain_vision2fiff, but the resulting fiff files do not contain any events. This is the command I run:

    $ mne_brain_vision2fiff --header R0026_eref3h.vhdr --out R0026_eref3h.fif

    mne_brain_vision2fiff version 1.7 compiled at Jan 7 2011 02:26:21

    header file : R0026_eref3h.vhdr
    output file : R0026_eref3h.fif

    Read header file : R0026_eref3h.vhdr
    Read header file : R0026_eref3h.vmrk

    nchan = 4
    sfreq = 500.0 Hz
    raw data file = R0026_eref3h.eeg
    raw binary = true
    raw binary type = 16
    raw endian = little
    raw nsamp = -1
    nevent = 0
    eXimia = false

    Data will be split into <= 1907.3 MByte pieces

    Writing header to R0026_eref3h_raw.fif ... [done]
    Writing raw data to R0026_eref3h_raw.fif ... Number of samples deduced from the raw file size : 628790
    [done]
    Wrote 1...628790 of 628790 samples total to R0026_eref3h_raw.fif
    Adding directory to R0026_eref3h_raw.fif...[done]

Eeglab finds the events so I assume the brain vision files are ok. Is this a known problem, or does anyone have an idea how to fix this? The files are small so if it helps I could upload them.

Thanks

-Christian

2

Hi Christian,

Please send the files so that I can have a look.

- Matti

3

Hi Christian,

Investigation of the code revealed that mne_brain_vision2fiff handles only events which are marked "Stimulus" and whose number is given by S<number>. In your file, the events are obviously user responses. The easy solution is to replace in R0026_eref3h.vmrk the word "Response" with "Stimulus" and "R128" with "S128". You can also simply change "Response,R" to "Stimulus,S".

I hope this helps.

- Matti

4

Thanks Matti! That solved the problem.

-Christian

5

hi Christian,

it would be great if you could send us a pull-request to add such info
to the doc:

http://www.martinos.org/mne/manual/convert.html#importing-brainvision-eeg-data

the corresponding doc file is:

https://github.com/mne-tools/mne-python/blob/master/doc/source/manual/convert.rst#importing-brainvision-eeg-data

thanks
Alex