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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Dear fieldtrip users,
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<div>I'm working with source estimations of EEG data. At the moment, I have estimated the sources at the individual level with individual MRIs. I've used ft_sourceinterpolate and ft_volumenormalise to transform the resulting estimation maps into a template
for comparison, and I do this for every subject: </div>
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<div> cfg = [];</div>
<div> cfg.parameter = 'avg.pow';</div>
<div> source = ft_sourceinterpolate(cfg, source, mri);</div>
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<div> cfg = [];</div>
<div> cfg.template = '\spm8\templates\T1.nii';</div>
<div> cfg.parameter = 'all';</div>
<div> cfg.nonlinear = 'yes';</div>
<div> cfg.coordsys = 'spm';</div>
<div> source = ft_volumenormalise(cfg, source); </div>
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<div>Once I have the estimated sources for all the subjects, I use ft_sourcestatistics:</div>
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<div>cfg = [];</div>
<div>cfg.dim = sourcePre_con{1}.dim;</div>
<div>cfg.method = 'montecarlo';</div>
<div>cfg.statistic = 'depsamplesT';</div>
<div>cfg.parameter = 'avg.pow';</div>
<div>cfg.correctm = 'cluster';</div>
<div>cfg.numrandomization = 'all';</div>
<div>cfg.alpha = 0.05;</div>
<div>cfg.tail = 0;</div>
<div>cfg.design(1,:) = [1:num 1:num];</div>
<div>cfg.design(2,:) = [ones(1,num) ones(1,num)*2];</div>
<div>cfg.uvar = 1;</div>
<div>cfg.ivar = 2; </div>
<div>stat = ft_sourcestatistics(cfg,sourcePost_con{:}, sourcePre_con{:});</div>
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<div>And I get this error:</div>
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<div><font color="#ff0000">Reference to non-existent field 'pos'.</font></div>
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<div><font color="#ff0000">Error in statistics_wrapper>get_source_avg (line 643)</font></div>
<div><font color="#ff0000"> fprintf('only selecting voxels inside the brain for statistics (%.1f%%)\n', 100*length(varargin{1}.inside)/size(varargin{1}.pos,1));</font></div>
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</font></div>
<div><font color="#ff0000">Error in statistics_wrapper (line 206)</font></div>
<div><font color="#ff0000"> [dat, cfg] = get_source_avg(cfg, varargin{:});</font></div>
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</font></div>
<div><font color="#ff0000">Error in ft_sourcestatistics (line 107)</font></div>
<div><font color="#ff0000"> [stat, cfg] = statistics_wrapper(cfg, varargin{:});</font></div>
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<div>I check the data structure and the structure of the sources at the individual level, before interpolating and normalising has the pos field, but after these steps, it's gone. How can I work around this error? Do I have to keep the pos field and transform
it according to the template?</div>
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<div>Thank you in advance for your help.</div>
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<div>Best regards,</div>
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<div>Laura Rueda</div>
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