eep and brainvision definetrial

Susana Silva zanasilva at GMAIL.COM
Tue May 6 19:33:57 CEST 2008


Hi Robert,
Thank you very much for the information.
In the mean time, I finally succeed in reading all brainvision files (yes,
there should have been a problem with bv format, because I had to change the
name of a field - to nChans- in the m file).

However, after rereading the documentation, I still have a local (and very
basic) question on the cfg for definetrial: what is a "dataset" when we are
using brainvision files? Can it be replaced by the header file, the data
file and the event/marker file? If so, what should bi included in the cfg
(cfg.datafile, cfg.headerfile, cfg.event?) I tried that but it did not work
out.

Concerning the arrangement of data so as to match definetrial output, I also
did this, based upon the documentation. However, this solution does not give
a prestimulus time, to be seen in each trial as referenced to a negative
time (eg: time -0.2 up to time 0) . I believe this is necessary to view the
baseline later.

Thank you again.
Best regards,
Susana Silva


On 5/6/08, Robert Oostenveld <r.oostenveld at fcdonders.ru.nl> wrote:
>
> Hi Susana,
>
> Your problem might well be to the file being exported in a non-standard
> brainvision format.
>
>
> On 27 Apr 2008, at 0:01, Susana Silva wrote:
>
> > My questions are:
> > -       In my position – someone who has eep files and brainvision
> > files,
> > what is the most simple option: try to use eep or brainvision (at the
> > moment, I can use neither!)
> >
>
> Reading the eep files requires mex files, and that requires additional
> software from ANT (a librarry with the low0-level routines). Since that
> software is not open source, it is not possible to recompile the MEX file on
> your platform. You could complain about the file format with ANT and/or get
> another Matlab version (an old matlab on windows should work). As such, the
> brainvision format seems the most pragmatic solution to me.
>
> -       Can you give me an example of a trial definition based upon a
> > brainvision file, let us say s1.eeg (data), s1.vhdr , s1.vmrk, where
> > 's33'
> > (eventvalue) is the 'Stimulus' (eventtype)?
> >
>
> Example trial definitions are given in the documentation on the fieldtrip
> website.
>
> -       In case I can not do the trial definition, how exactly should I
> > arrange my data so that they are equivalent to the output of
> > "definetrial"?
> >
>
> You should specify a trl matrix as cfg.trl to the preprocessing function,
> that matrrix is explained in the documentation on the website and in the
> definetrial function help.
>
> best regards,
> Robert
>
> ----------------------------------
> The aim of this list is to facilitate the discussion between users of the
> FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG
> and EEG analysis. See also
> http://listserv.surfnet.nl/archives/fieldtrip.html and
> http://www.ru.nl/fcdonders/fieldtrip.
>

----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/fcdonders/fieldtrip.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20080506/fc17a6bd/attachment-0002.html>


More information about the fieldtrip mailing list