Freqstatistics Yields Zero Significant Clusters?

[Charles Cook]

Hi Eric,

Yes that did seem to a further unusually high number, especially since
they're all standard-81! Let me give you an idea of where our code is
presently at:

============================================

cfg = [];
cfg.neighbourdist    = 4;
cfg.elec             = elec;
cfg.statistic        = 'indepsamplesT';
cfg.minnbchan        = 0;
cfg.clusteralpha     = 0.05;
cfg.alpha            = 0.05;
cfg.clustertail      = 0;
cfg.numrandomization = 5000;

cfg.latency          = [250 500];
cfg.frequency        = [4 7];
cfg.avgovertime      = 'no'; 
cfg.avgoverfreq      = 'no';
cfg.avgoverchan      = 'no';

cfg.correctm         = 'cluster';
cfg.method           = 'montecarlo';
cfg.feedback         = 'gui';
cfg.design           = [1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
21 22;   % subject number
                        1 1 1 1 1 1 1 1 1 1  1  2  2  2  2  2  2  2  2  2  2
 2]; % condition number
                          
cfg.uvar = 1;                                   % "subject" is unit of
observation
cfg.ivar = 2;                                   % "condition" is the
independent variable
stat = freqstatistics(cfg, malefeat_all, femloc_all);

%cfg = [];
%[freq_maleloc] = freqdescriptives(cfg, maleloc_all);
%[freq_femloc]  = freqdescriptives(cfg, femloc_all);

cfg = [];
cfg.zlim = [-6 6];
cfg.alpha = 0.05;
clusterplot (cfg, stat); <----still failing here

============================================

Reading power on 81 channels
not computing grand average, but keeping individual power for 11 subjects
not computing grand average, but keeping individual power for 11 subjects
selected 81 channels
selected 6 time bins
selected 4 frequency bins
Warning: PACK can only be used from the MATLAB command line.
> In fieldtrip\private\prepare_timefreq_data at 310
  In fieldtrip\private\statistics_wrapper at 206
  In freqstatistics at 132
  In CMCWM2_std81_junk_with at 144
Obtaining the electrode configuration from the configuration.
there are on average 83.0 neighbours per channel
using "statistics_montecarlo" for the statistical testing
using "statfun_indepsamplesT" for the single-sample statistics
constructing randomized design
total number of measurements     = 22
total number of variables        = 2
number of independent variables  = 1
number of unit variables         = 1
number of within-cell variables = 0
number of control variables      = 0
using a permutation resampling approach
repeated measurement in variable 1 over 22 levels
number of repeated measurements in each level is 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 
computing a parmetric threshold for clustering
estimated time per randomization is 0 seconds
found 2 positive clusters in observed data
found 1 negative clusters in observed data
using a cluster-based method for multiple comparison correction
the returned probabilities and the thresholded mask are corrected for
multiple comparisons
??? Assignment has more non-singleton rhs dimensions than non-singleton
subscripts

Error in ==> clusterplot at 91
    sigposCLM(:,:,iPos) = (posCLM == sigpos(iPos));

Error in ==> CMCWM2_std81_junk_with at 153
clusterplot (cfg, stat);

============================================

Should our cfg.neighbourdist have a higher number if we are using a
Standard-81 layout? We've tried a few different variations with that number
and still ended up with the same error.

Cheers,

Charles

On Mon, 8 Jun 2009 17:00:22 +0200, Eric Maris <e.maris at DONDERS.RU.NL> wrote:

>Hi Charles,
>
>83.0 neighbours per channel does not make sense. For EEG-channels this
>number typically is 4 and for MEG-channels it is typically 6. Have a look at
>the neighbourhood geometry structure that is constructed by freqstatistics.
>I guess this structure is far too wide (a channel is considered a neighbour
>of almost every other channel).
>
>
>Best,
>
>Eric
>

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