[FieldTrip] is beamforming result correct?

[Rojas, Don]

Ion,

I do not think we can say definitively if your result is incorrect or not with the information provided. Can you provide a summary of your task, preprocessing and source analysis steps? There are MEG papers using beamformers that reveal cerebellar activity that is task consistent. If you do not have any a priori reason to expect it, however, then perhaps you are correct.

Best,

Don
-----------------------
Don Rojas, Ph.D.
Associate Professor of Psychiatry
U. of Colorado Denver Anschutz Medical Campus
Director, UCD Magnetoencephalography Lab


On Mar 22, 2012, at 10:13 AM, Ion Lavado wrote:

> I think the result i got doing the beamforming source reconstruction is not good as there is lot of activation at the bottom where the cerebellum is. Can anyone confirm me it is incorrect? Possible mistake?
> 
> This is the code i used for the headmodel:
> 
> mri = ft_read_mri('/home/ilavado/ilavado/mutiT1/T1_02.mgz');
> cfg = [];
> cfg.interactive    = 'yes';
> cfg.coordsys    = 'neuromag';
> mri_real           = ft_volumerealign(cfg,mri); 
> [segmentedmri]   = ft_volumesegment(cfg, mri_real)
> cfg = [];
> cfg.sourceunits='cm';
> cfg.coordsys       = 'neuromag';
> vol02 = ft_prepare_singleshell(cfg, segmentedmri);
> ft_plot_vol(vol02);
> mri_real = rmfield(mri_real, 'pnt');
> 
> sourceDiff = source_post;
> sourceDiff.avg.pow = (source_post.avg.pow - source_pre.avg.pow) ./ source_pre.avg.pow;  
> cfg            = []
> cfg.downsample = 2;
> sourceDiffInt  = ft_sourceinterpolate(cfg, sourceDiff , mri_real);
> cfg = [];
> cfg.coordsys      = 'ctf';
> cfg.nonlinear     = 'no';
> sourceDiffIntNorm = ft_volumenormalise(cfg, sourceDiffInt);
> 
> Thank you very much. 
> 
> Best,
> 
> Ion
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