[FieldTrip] MNI grid alignment in subjects for group comparison
johanna.zumer at donders.ru.nl
Fri Jan 11 17:50:32 CET 2013
I agree that sentence is not phrased ideally. It is refering to the
source data structure, i.e. the output of ft_sourceanalysis. Specifically,
copy the template_grid.pos to source.pos and then this updated source data
structure can be used in ft_sourcegrandaverage. Likewise,it can be
overlaid on the MNI brain. I'm not sure if the other fields are
necessary, if they are, maybe someone else can comment.
2013/1/11 Marco Curado <marco.curado at yahoo.com.br>
> Dear Fieldtrip experts,
> I have a question on MNI aligned grids for subjects head prior to source
> In my experimental design, there are three experimental conditions (A, B
> and C) I want to compare in one group of subjects at the source level. To
> be able to compare source activity (by LCMV beamforming) among them, I use
> the MNI grid warped in every subject's head (to allow comparison at the
> source level) as stated in the tutorial "Create MNI-aligned grids in
> individual head-space":
> Up to now, everything is ok. But as I am naive in beamforming, I am a bit
> confused on the last sentence of this tutorial, where it is stated:
> "You can use these single subjects' MNI grids in source analysis. After
> that you should put .pos, .xgrid, .ygrid, .zgrid, .dim field from the
> template_grid onto the subjects's source, which is thereby in MNI
> My question (indeed very basic) is what is exactly referred as the
> subject's source? Is it the final source localization after LCMV? I.e., do
> I need to insert such template_grid parameters in subject's parameter as
> last step after all source localization?
> Summing up: The procedure would be to use the .grid from the subject
> (already warped with MNI grid) for source localization with LCMV and after
> it I include these parameters from the template-grid?
> Thanks a lot for your comprehension and attention to my question - I hope
> I was clear in my issue.
> My best wishes of an excellent year to everybody,
> Marco Curado
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
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