[FieldTrip] source statistics - spm_bwlabel error

[Malgorzata Wislowska]

Dear Julian,


thank you very much for your prompt response.

Yes, my numdims == 2 because my cfg.dim == [8196 1]
which comes from ft_sourcestatistics.m (code lines 131-132)

datdim = find(~strcmp(dimtok, 'subj') & ~strcmp(dimtok, 'rpt') &
~strcmp(dimtok, 'rpttap'));
datsiz = dimsiz(datdim);

calculated on the following input data:

varargin{1}:
       cfg: [1x1 struct]
    inside: [8196x1 logical]
       pos: [8196x3 double]
      time: 0.1750
       pow: [8196x1 double]
    dimord: 'chan_time'

The above source level structure comes from ft_sourceanalysis calculated
with cfg.method = 'mne'.

Averaging over time unfortunately doesn't help - the same error continues
to occur:
But data that is not averaged over time has numdims == 2 too, because
length(cfg.dim) == 2, even though that cfg.dim itself is different (for not
averaged data it's e.g cfg.dim == [8196 61], whereas for averaged data it's
cfg.dim == [8196 1]),

It helps (well, the function runs through without errors and produces some
output) if the line:

if numdims == 2 || numdims == 3 % if 2D or 3D data

gets replaced with:

if numdims == 3

In clusterstat.m, code line: 318 (and also 269, 215, 184)

Do you (or anybody else) have maybe any better idea how to fix it?


Thanks and best regards,
Malgorzata,
University Salzburg




> Subject: Re: [FieldTrip] source statistics - spm_bwlabel error
>


Dear Malgorzata,
>
> from a quick glance, it appears that in the call to spm_bwlabel "numdims"
> should be 3 to give you 2*numdims = 6.
> So, could you check what numdims is in your case?
> I suspect that you have 4-dimensional data (time by 3 spatial dimensions),
> so it might help to check where the dimensions are coming from and what
> happens if you average over time.
>
> Good luck,
>
> Julian
>
> Am 24.05.2017 um 16:34 schrieb Malgorzata Wislowska:
>
> Dear FT-community,
>
>
> when calculating cluster permutation statistics on the source level, I
> receive the following error:
>
> Error using spm_bwlabel
> spm_bwlabel: CONN must be 6, 18 or 26
>
> Error in clusterstat (line 319)
>         [negclusrnd, negrndnum] = spm_bwlabel(tmp, 2*numdims); % use
> spm_bwlabel for 2D/3D to avoid usage of image toolbox
>
> Error in ft_statistics_montecarlo (line 347)
>   [stat, cfg] = clusterstat(cfg, statrand, statobs);
>
> Error in ft_sourcestatistics (line 218)
>   [stat, cfg] = statmethod(cfg, dat, design);
>
>
> I used MNE method for the inverse problem. I have 8196 grid points 1555
> time points.
> But the error occurs also when I average across the time.
>
> Here is my configuration structure for the source analysis:
>
>
> design          = zeros(2, nb_of_sbj*2);
> design(1,:)   = [1:nb_of_sbj 1:nb_of_sbj];
> design(2,:)     = [ones(1,nb_of_sbj) ones(1,nb_of_sbj)*2];
>
> cfg                     = [];
> cfg.method              = 'montecarlo';
> cfg.statistic           = 'ft_statfun_depsamplesT';
> cfg.parameter           = 'pow';
> cfg.correctm            = 'cluster';
> cfg.clusterstatistic    = 'maxsum';
> cfg.design              = design;
> cfg.ivar                = 2;
> cfg.uvar                = 1;
> cfg.numrandomization    = 5000;
> cfg.tail                = 0;
> cfg.alpha               = 0.025;
>
> [stat]                  = ft_sourcestatistics(cfg,avg_co
> n_sel{:},avg_incon_sel{:});
>
>
> As far as I can see somebody had asked the same question last year, but
> the post doesn't seem to have been addressed:
> https://mailman.science.ru.nl/pipermail/fieldtrip/2016-August/010762.html
>
>
> Thank you for your help in advance.
>
> Best regards,
> Malgorzata Wislowska,
> University of Salzburg
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