Transformation from head to MEG coordinate

[Vladimir Litvak]

Dear Kaoru,

1) There is no requirement to provide the grid in head coordinates.
vol, grid and sensors can be in any coordinate system as long as it is
the same system.

2) What do you use to read sensor positions and fiducials for
Yokogawa? The code available in Fieldtrip at the moment is incomplete
and would not allow you to use the beamformer. If you have something
better, we'd be very interested in integrating your code.

3) There are some functions in Fieldtrip to do coregistration. Look at
electroderealign and interactiverealign.

4) SPM8b (http://www.fil.ion.ucl.ac.uk/spm/software/spm8b/) which is
very well integrated with Fieldtrip has some facilities for
coregistering sensors and head models using GUI. The resulting
coregistered volume in sensors can be used for beamforming in
Fieldtrip. But this wil only work with proper Yokogawa support which
we lack at the moment.

Best,

Vladimir


On Fri, Dec 12, 2008 at 6:02 AM, Kaoru Amano
<amano at brain.k.u-tokyo.ac.jp> wrote:
> Dear all
>
> We are using Yokogawa's MEG system and are trying to do source localization
> using fieldtrip.
>
> In "prepare_leadfield.m", dipole grid is supposed to be provided in head
> coordinate, while sensor location is defined in MEG coordinate. For the
> registration between head and MEG coordinates, we need to specify the
> information of head positioning, in which we get MEG coordinates of three
> markers.
>
> Could you tell me how we can specify the information of head positioning?
>
>
> Best,
> Kaoru
>
>
>
> --
> Kaoru Amano
> email: amano at brain.k.u-tokyo.ac.jp
> URL: http://www.brain.k.u-tokyo.ac.jp/~amano/
>
> ----------------------------------
> 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.