[FieldTrip] About co-register the individual sudbject MRI and sensor locations

[jan-mathijs schoffelen]

Hi Xiaoxiao,

It looks as if your mri (from which you obtained the vol-variable) and the data in the hs_file are not expressed in the same coordinate system. The geometrical objects that you need to combine in order to compute leadfields should be defined in the same coordinate system. My guess is that you will first need to apply ft_volumerealign to your mri_nom variable, to get it back into the Bti-based coordinate system. 

Best,

Jan-Mathijs


On Jul 21, 2012, at 1:28 AM, Bai, XiaoXiao wrote:

> Dear Sir/Madam,
>  
> I am a new fieldtrip user and want to apply the beamformer method in Fieldtrip for the MEG data from 4D/BTI system. Now I can get a individual subject MRI in analysis/spm format from CURRY software.
>  
> This is my code for create volume head model for the beamformer,
>  
> mri_nom = ft_read_mri(mrifile);
>  
> cfg = [];
> [segmentedmri] = ft_volumesegment(cfg, mri_nom);
>  
> cfg = [];
> cfg.method = 'singleshell';
> vol = ft_prepare_headmodel(cfg, segmentedmri);
>  
> The vol and sensor locations were displayed and attached with here.
>  
> How can I co-register the vol with sensors based on headshpe file (hs_file) for computing lead field for next step?
>  
> Thanks a lot.
>  
> Best regards,
>  
> Xiaoxiao
> Division of Clinical Neurosciences, Department of Pediatrics
> University of Tennessee Health Science Center, College of Medicine &
> Neuroscience Institute, LeBonheur Children's Hospital
> 777 Washington Avenue, P335
> Memphis, TN 38105, USA
> Phone: 901-287-4612
> Fax: 901-287-5325
> <sensor and volume.png>_______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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