Problem with data from BESA

Stephan Moratti stephan.moratti at UNI-KONSTANZ.DE
Wed Nov 16 13:13:33 CET 2005

Hi Michael,

I often use BESA exported data with many different tools. One problem I
encountered often, is that the coordinate system applied was not
compatible. Sometimes I had to shift the whole thing by 90 degrees or so.
As you are using sfp files (containing x,y,z coordinates), this could be
the problem. But I am not sure as I havent't imported to fieldtrip yet.
Maybe just a hint, maybe not.


At 12:21 16.11.2005 +0100, you wrote:
>    Hi,
>  EEG data from BESA (std 81 electrodes, average refrence) using the .mul
>format and the corresponding .sfp file to import the electrode locations.
>The import into fieldtrip seems to work fine with these formats (it didn't
>when I tried .avr and .elp...). However, the maps look very different from
>what I see in BESA (more like something differentiated / inverted from the
>BESA maps - the foci are clearly shifted). Do I have to tell Fieldtrip
>somewhere that this is EEG data, so that it doesn't do the things it would
>when dealing with MEG gradiometer data? Or is there something I have to do
>to let fieldtrip know that the data are average reference data. I can't
>find anything in the tutorials on this matter.
> Thank you very much for any help on this,
> Michael Wibral
> M. Wibral Dipl. Phys.
> Max Planck Institute for Brain Research
> Dept. Neurophysiology
> Deutschordenstrasse 46
> 60528 Frankfurt am Main
> Germany
>      +49(0)69/6301-83849
>             +49(0)173/4966728
>        +49(0)69/96769-327

Dr. Stephan Moratti (PhD)
Dept. of Psychology
University of Konstanz
P.O Box D25
Phone: +40 (0)7531 882385
Fax: +49 (0)7531 884601
D-78457 Konstanz, Germany
e-mail: Stephan.Moratti at

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