[FieldTrip] Cannot read the events of a .BDF file exported from an EGI .RAW

Thu Jun 5 17:56:38 CEST 2014

Hi Ana, During our last fieldtrip meeting, we discussed about the triggering issues with the *RAW file format and here some thoughts: 1) What you reported is not a fieldtrip problem per se. The way NETSTATION is configured in your lab allow you to record the triggers in bits, not in decimal numbers. I don't know how but there should be a way to configure your acquisition device in such a way that triggers are not transform from decimal to binary representation. 2) Make your own trialfun to solve the conversion problem. I created a FAQ titled "How can I transform trigger values from bits to decimal representation with a trialfun?" on where you'll find code to make the transition from bits to decimals again. This FAQ could also be useful for other users having similar problems (binary to decimal conversion) with other acquisition systems. I hope this helps Diego ----- Original Message -----
> From: "Ana Laura Diez Martini" <diezmartini at gmail.com>
> To: "Diego Lozano" <d.lozanosoldevilla at fcdonders.ru.nl>, "FieldTrip
> discussion list" <fieldtrip at science.ru.nl>
> Sent: Tuesday, 27 May, 2014 12:25:39 AM
> Subject: Re: [FieldTrip] Cannot read the events of a .BDF file
> exported from an EGI .RAW
> Thank you Arjen, Diego and Chungki Lee!
> I tried with the .RAW and it reads the event. The problem is that my
> triggers have the following format "11,12,13,14,15,21,22...." .
> Netstation instead of saving them as they are, returns them in this
> way: say my trigger is 12, I get "DIN4" and "DIN8". or 11 is DIN1 +
> DIN8 + DIN2. so I had to convert them into my original triggers. After
> that I can either save the set (I tried this but it didn't work) or
> export it to bdf. When I open the exported file in EEGlab, it reads
> the events correctly, but fieldtrip doesn't.
> Any ideas? Thanks!!
> On Mon, May 26, 2014 at 9:44 PM, Lozano Soldevilla, D. (Diego) <
> d.lozanosoldevilla at fcdonders.ru.nl > wrote:
> > Dear Ana,
> > Sorry for my file extension confusion: edf instead of bdf. However,
> > I
> > don't know a way to read events coded in BDF format exported by
> > NETSTATION. I encounter this problem in the past but I had no
> > problems
> > with RAW file format
> > Dear Chungki,
> > Fieldtrip can read events in *.bdf but from BIOSEMI eeg system but
> > Ana
> > was refering to a different eeg system that has the same fileformat
> > extension.
> > best,
> > Diego
> > > From: "Chungki Lee" < dr.chungki.lee at gmail.com >
> > > To: "FieldTrip discussion list" < fieldtrip at science.ru.nl >
> > > Sent: Monday, 26 May, 2014 11:18:34 AM
> > > Subject: Re: [FieldTrip] Cannot read the events of a .BDF file
> > > exported from an EGI .RAW
> > > Dear all
> > > Fieldtrip can read events in BDF format !
> > > Hear simple examples
> > > example #1
> > > %%
> > > cfg = [];
> > > cfg.dataset = '~~~ '; % your filename with file extension;
> > > cfg.trialdef.eventtype = 'STATUS'; % Status notation maybe
> > > Biosemi's
> > > tigger name
> > > cfg.trialdef.eventvalue = 1; % your event value
> > > cfg.trialdef.prestim = 4; % before stimulation (sec), only use
> > > positive value
> > > cfg.trialdef.poststim = 8; % after stimulation (sec) , only use
> > > positive value
> > > cfg = ft_definetrial(cfg);
> > > cfg.method = 'trial';
> > > data = ft_preprocessing(cfg);
> > > %%
> > > example #2
> > > %%
> > > % if you executed these command lines
> > > cfg = [];
> > > cfg.dataset = '~~~ '; % your filename with file extension;
> > > cfg.trialdef.eventtype = '?'; % Status notation maybe Biosemi's
> > > tigger
> > > name
> > > cfg = ft_definetrial(cfg);
> > > % result example #2
> > > the following events were found in the datafile
> > > event type: 'CM_in_range' with event values:
> > > event type: 'Epoch' with event values:
> > > event type: 'STATUS' with event values: 1 2 3 4 255 <-----------
> > > "this
> > > indicate your file configuration for trigger information"
> > > no trials have been defined yet, see FT_DEFINETRIAL for further
> > > help
> > > found 255 events
> > > created 0 trials
> > > the call to "ft_definetrial" took 8 seconds
> > > have fun~!!
> > > 2014-05-26 17:58 GMT+09:00 Diego Lozano Soldevilla <
> > > d.lozanosoldevilla at fcdonders.ru.nl > :
> > > > Hi Ana,
> > > > Fieldtrip does not read events in BDF format. Take a look to our
> > > > wiki:
> > > > http://fieldtrip.fcdonders.nl/getting_started/egi
> > > > •
> > > > EDF+ (.edf) All channels, including PIB channels, are read in
> > > > correctly, including channel labels. However, the events, which
> > > > are
> > > > stored on the annotation channel, are written in a way by Net
> > > > Station
> > > > that is not compatible with the edf+ reading implementation in
> > > > FieldTrip. So, events do not come out properly. Also
> > > > discontinuous
> > > > epochs are “glued” together as one “continuous” data stream.
> > > > As Arjen suggested, with *.RAW you shouldn't have any problem.
> > > > event = ft_read_event('*.RAW')
> > > > If you encounter it, please let us know.
> > > > best,
> > > > Diego
> > > > On 26 May 2014 08:59, Arjen Stolk < a.stolk8 at gmail.com > wrote:
> > > > > Hi Ana Laura,
> > > > > Have you tried importing the .RAW file directly? That is, by
> > > > > specifying cfg.dataset = 'XXX.raw'?
> > > > > Best regards,
> > > > > Arjen
> > > > > 2014-05-26 2:30 GMT+02:00 Ana Laura Diez Martini <
> > > > > diezmartini at gmail.com > :
> > > > > > Hi all!
> > > > > > This is the .BDF file of one of my EEG subjects. For my last
> > > > > > experiment I used a Biosemi system and now I'm using an EGI
> > > > > > system
> > > > > > which gives me .RAW files. I exported the .RAW file with
> > > > > > EEGlab
> > > > > > to
> > > > > > .BDF format and I tried using the scripts I use to analise
> > > > > > the
> > > > > > data
> > > > > > of
> > > > > > my previous experiment but I realised that it was not
> > > > > > reading
> > > > > > the
> > > > > > events:
> > > > > > cfg = [];
> > > > > > cfg.dataset = ' (location)';
> > > > > > cfg.trialdef.eventtype = '?';
> > > > > > definetrial(cfg);
> > > > > > Warning: no trialfun was specified, using trialfun_general
> > > > > > > In definetrial at 79
> > > > > > evaluating trialfunction 'trialfun_general'
> > > > > > no events were found in the datafile
> > > > > > no trials have been defined yet, see DEFINETRIAL for further
> > > > > > help
> > > > > > found 0 events
> > > > > > created 0 trials
> > > > > > EEGlab does read them. Any idea of what could be wrong?
> > > > > > Thank you all!!
> > > > > > _______________________________________________
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> > > > > > fieldtrip at donders.ru.nl
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> > > --
> > > ----------------------------------------------------------------
> > > Chungki Lee, Ph.D.
> > > Post-doc
> > > Biomedical Research Institute
> > > Korea Institute of Science and Technology
> > > E-mail: chungki at kist.re.kr
> > > Tel: +82-2-958-5636 , C.P: +82-10-5223-7309
> > > ----------------------------------------------------------------
> > > _______________________________________________
> > > fieldtrip mailing list
> > > fieldtrip at donders.ru.nl
> > > http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> > --
> > PhD Student
> > Neuronal Oscillations Group
> > Donders Institute for Brain, Cognition and Behaviour
> > Centre for Cognitive Neuroimaging
> > Radboud University Nijmegen
> > NL-6525 EN Nijmegen
> > The Netherlands
> > http://www.ru.nl/people/donders/lozano-soldevilla-d/
> > _______________________________________________
> > fieldtrip mailing list
> > fieldtrip at donders.ru.nl
> > http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
-- PhD Student Neuronal Oscillations Group Donders Institute for Brain, Cognition and Behaviour Centre for Cognitive Neuroimaging Radboud University Nijmegen NL-6525 EN Nijmegen The Netherlands http://www.ru.nl/people/donders/lozano-soldevilla-d/
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