[FieldTrip] beamforming - normilise issue

["Jörn M. Horschig"]

Dear Davide,

I was hesitant to answer, because I thought others know more than me. 
But since none responded, I can try to help with my limited knowledge.

 From my knowledge of source reconstruction, I can just say that if all 
your source reconstructions are in the same space (say, MNI), you can 
use the .pos from your template to overcome this problem. I am not using 
ft_volumenormalise, so I have no experience what is exactly going on 
there. I would assume, however, that volumenormalise will transofmr your 
source structures to a common space.
However, I stick to normalizing the following way:
http://fieldtrip.fcdonders.nl/example/create_single-subject_grids_in_individual_head_space_that_are_all_aligned_in_mni_space

Hope it helps at least a little bit.
Best,
Jörn

On 10/19/2011 6:12 PM, Davide Rivolta wrote:
> Hi Michael,
> I am using the single shell (Nolte).
> The grid has 2340 positions, but I am not still using mni.
> Thanks,
> Davide
>
> On Wed, Oct 19, 2011 at 5:44 PM, Michael Wibral <michael.wibral at web.de 
> <mailto:michael.wibral at web.de>> wrote:
>
>     Hi davide,
>
>     what headmodel and grid are you using?
>
>     Michael
>
>
>         ------------------------------------------------------------------------
>         *Von:* "Davide Rivolta" <drivolta81 at gmail.com
>         <mailto:drivolta81 at gmail.com>>
>         *Gesendet:* Oct 19, 2011 3:54:37 PM
>         *An:* "Email discussion list for the FieldTrip project"
>         <fieldtrip at donders.ru.nl <mailto:fieldtrip at donders.ru.nl>>
>         *Betreff:* [FieldTrip] beamforming - normilise issue
>
>
>         Dear all,
>         I am trying to use beamforming for some MEG data.
>         I have 1 condition, and I wish to compare it against the
>         baseline. Ideally I wish to have the average of all group and
>         statistically compare stimulus agains baseline..
>         As such, for each subject I calculate the source for the
>         baseline and the source for the stimulus (using a common
>         filter as indicated on the website).
>         I then call ft_sourceinterpolate and, since I wish to have a
>         group analysis, ft_volumenormalise.
>         In order to compute the average, I call ft_sourcegrandaverage.
>         Even though the help tells me that it is fine, the
>         grandaverage does not work if the input is from the
>         ft_volumenormalise. It is because there is not the ".pos" field!
>         Am I doing something wrong?
>         Any advice would be great.
>         Thanks a lot,
>         Davide
>
>
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>
>
>
>
> -- 
> Davide Rivolta, PhD
>
>
>
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-- 
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group

P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands

Contact:
E-Mail: jm.horschig at donders.ru.nl
Tel:    +31-(0)24-36-68493
Web: http://www.ru.nl/donders

Visiting address:
Trigon, room 2.30
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NL-6525 EN Nijmegen
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