[FieldTrip] error in source parcellation and source connectivity analysis

velmurugan jayabal velmurugan.nimhans at gmail.com
Sun Apr 9 02:54:43 CEST 2017


Dear Field-trip community,

I am having the following errors when computing connectivity
analysis. Please any help in this regard would be highly appreciated.
Thanks in advance.

1. How to compute atlas based source model grid, from MMP atlas?. Since MMP
atlas doesn't contain the *dim *field, the ft_volumelookup function doesn't
work prompting me the same error.


2. Alternatively, I had created AAL atlas based source model grid and used
to compute source connectivity (img.coh) from PCC beamformer source output.
But, I am unable to compute the connectivity value for each parcel using
ft_sourceparcellate. I am writing the codes used to derive the same.

3. Is there any acronym or a clear explanation for the parcellation label?.
I had read Glasser et al 2016 paper and their resource site. But, I
couldn't get complete names or explanation for all the ROIs.


CODE:
%source is the output of pcc beamformer results.
cfg         = [];
cfg.method  ='coh';
cfg.complex = 'absimag';
source_conn_imcoh = ft_connectivityanalysis(cfg, source);

atlas =ft_read_atlas ('ROI_MNI_V5.nii');
atlas.pos =source_conn_imcoh.pos;
cfg =[];
cfg.method ='mean'
cfg.parameter ='cohspctrm';
cfg.parcellation = 'tissue';
parc_conn= ft_sourceparcellate(cfg,source_conn, atlas);

I had even tried computing source connectivity interpolation on the atlas
before parcellation. But, I am getting a huge array > 50 GB, which exceeds
my MATLAB and system limit.


-- 
- sincerely,
*Velmurugan Jayabal,*
*Magnetoencephalography (MEG) research centre,*
*Department of Clinical Neurosciences,*

*National Institute of Mental Health and Neurosciences (NIMHANS),*
*Bangalore - 560029, Karnataka, India*
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