[FieldTrip] Help with ft_sourcestatistics input

[Xavier Vrijdag]

Hi Tao,


I am not sure about the cfg.neighbours setting, but the error looks like a SPM version issue I had before as well. I solved it by adding:

cfg.spmversion       = 'spm12';

regards,

Xavier

From: fieldtrip <fieldtrip-bounces at science.ru.nl> on behalf of Tao Wang <wangtao0331 at tju.edu.cn>
Reply to: FieldTrip discussion list <fieldtrip at science.ru.nl>
Date: Friday, 24 July 2020 at 3:26 AM
To: "fieldtrip at science.ru.nl" <fieldtrip at science.ru.nl>
Subject: [FieldTrip] Help with ft_sourcestatistics input

Dear community,

My name is Tao Wang and I study at Tianjin University. My research direction is to explore ways(tDCS\tACS) to improve working memory. I’m looking to perform a cluster-based permutation test on my source data(the result from ft_sourceanalysis).

I carefully read the function help and the tutorial(http://www.fieldtriptoolbox.org/example/source_statistics/). However, I receive the following error message:

Error using spm_bwlabel
spm_bwlabel: CONN must be 6, 18 or 26
Error in clusterstat (line 191)
      [posclusobs, posnum] = spm_bwlabel(tmp, 2*numdims);
Error in ft_statistics_montecarlo (line 353)
  [stat, cfg] = clusterstat(cfg, statrand, statobs);
Error in ft_sourcestatistics (line 202)
  [stat, cfg] = statmethod(cfg, dat, design);

I am running the following:
cfg=[];
cfg.parameter='pow';
cfg.method='montecarlo';
cfg.statistic = 'ft_statfun_depsamplesT';
cfg.correctm = 'cluster';
cfg.clusteralpha = 0.05;
cfg.clusterstatistic = 'maxsum';
cfg.tail=0;
cfg.clustertail=0;
cfg.alpha=0.025;
cfg.numrandomization = 1000;
nsubj = 10;
cfg.design(1,:) = [1:nsubj 1:nsubj];
cfg.design(2,:) = [ones(1,nsubj)*1 ones(1,nsubj)*2];
cfg.uvar        = 1; % row of design matrix that contains unit variable (in this case: subjects)
cfg.ivar        = 2; % row of design matrix that contains independent variable (the conditions)

stat = ft_sourcestatistics(cfg, grandavgA{:}, grandavgB{:});

My data:
display (grandavgA{1})
time: [1×400 double]
inside: [8196×1 logical]
pos: [8196×3 double]
tri: [16384×3 double]
method: 'average'
avg: [1×1 struct]
cfg: [1×1 struct]
display(grandavgA{1}.avg)
  mom: {1×8196 cell}
  pow: [8196×1 double] %I used ‘8196×1 double’ instead of ‘8196×400 double’
  noisecov: {1×8196 cell}

Do I need to set cfg.neighbours, like the settings in the tutorial "Cluster-based permutation tests on event related fields"? (I noticed cfg.dim, but it doesn’t appear in my source struct)
Can someone tell me if there is something wrong with the cfg settings I use or if I am doing something wrong at any other place? Any tips anyone has would be very much appreciated!
Hope that helps!

    Best,
    Tao
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