[FieldTrip] Quality of beamforming on MNI template vs single-subject MRI

[smoratti at psi.ucm.es]

Dear Andrea,

¿Did you normalize the volume of the individuals after source reconstruction and before doing statistics? If not, this might explain the difference.

best,

Stephan

________________________________________________________
Stephan Moratti, PhD

see also: http://web.me.com/smoratti/

Universidad Complutense de Madrid
Facultad de Psicología
Departamento de Psicología Básica I
Campus de Somosaguas
28223 Pozuelo de Alarcón (Madrid)
Spain

and

Center for Biomedical Technology
Laboratory for Cognitive and Computational Neuroscience
Parque Científico y Tecnológico de la Universidad Politecnica de Madrid
Campus Montegancedo
28223 Pozuelo de Alarcón (Madrid)
Spain


email: smoratti at psi.ucm.es
Tel.:    +34 679219982

El 04/04/2013, a las 14:18, Andrea Brovelli escribió:

> Dear all,
> 
> I used DICS and compared the quality of the beamforming using two different source spaces (3D grids):
> 
> 1) MNI template space as described in http://fieldtrip.fcdonders.nl/example/create_single-subject_grids_in_individual_head_space_that_are_all_aligned_in_mni_space
> 
> 2) Single subject 3D grid using anatomical MRI
> 
> The number of sources in the two models is similar (approx. 3500 sources). However, the results using the MNI template are less significant. That is, the statistical analysis testing a significant increase in power post-stimulus with respect to baseline give higher p-values (in some region of interest).
> 
> Questions:
> 
> Does anyone know why ?
> 
> Is the use of the MNI template the only (and best) way to allow statistical analysis across subjects in the source space ?
> 
> thanks a lot
> 
> Andrea
> 
> 
> 
> -- 
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