coordinate mismatch in ASA headmodel and *.nii -files

[Nathan Weisz]

dear gregor,

it seems like you left out some co-registration steps.

if you have the ASA vol, the mri (*.mri; read_asa_mri.m) then you still need the co-registered electrode positions. can't you just export those from ASA too? otherwise ft_volumerealign, then apply transformation matrix to you electrode positions so that they are in the same coordinate system as your vol & mri?

cheers & good luck,
n





On 28.09.2010, at 12:41, Gregor Volberg wrote:

> Dear fieldtrippers,
>
> thanks a lot for the helfulp comments on my former source analysis questions. This one is maybe not directly related to fieldtrip's source analysis functions:
> I use individual headmodels generated by ASA software (which reads and segments MRI images in Siemens DICOM format) for source reconstruction. The corresponding anatomical data is in an *nii-file, generated with the DICOM-import function if SPM5. Now, when I plot the individual functional data overlayed on the individual anatomical data, it seems that X and Y coordinates are exchanged, Y ist rotated by 90 or -90 degrees, and Z is shifted into positive direction for functional compared to structural data. I tried to normalize the volume data with ft_volumenormalise using the individual MRI as template file, but this warps both functional and anatomical data so that the mismatch between both is still there.
>
> Did some ASA-user have a similar problem - is there maybe a necessary transformation  that I have overlooked? Thanks again in advance -
> Gregor
>
>
>
> --
> Dr. rer. nat. Gregor Volberg <gregor.volberg at psychologie.uni-regensburg.de> ( mailto:gregor.volberg at psychologie.uni-regensburg.de )
> University of Regensburg
> Institute for Experimental Psychology
> 93040 Regensburg, Germany
> Tel: +49 941 943 3862
> Fax: +49 941 943 3233
> http://www.psychologie.uni-regensburg.de/Greenlee/team/volberg/volberg.html
> ----------------------------------
> 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/neuroimaging/fieldtrip.

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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/neuroimaging/fieldtrip.