[FieldTrip] Error: Could not determine the parametric critical value for clustering

[Paul Dhami]

Dear Stephen,

apologizes for not including that information.

The data structure (e.g. ControlsSubj_sp_lpfc_freq) was created using:

  % frequency analysis

  cfg                 = [];

  cfg.output          = 'powandcsd';

  cfg.method          = 'mtmconvol';

  cfg.foi             = 2:1:60; %40

  cfg.t_ftimwin       =  2 ./ cfg.foi; %length of the sliding time window
in seconds

  cfg.tapsmofrq       = 0.4 *cfg.foi; % smoothing increases with increase
in freq

  cfg.toi             = -1:0.01:1; % -0.4:0.01:0.4



  dataSPfreq = ft_freqanalysis(cfg, dataSPfreq);



  %baseline correction

  cfg = [];

  cfg.baseline = [-1 -0.1]; %-0.4

  cfg.baselinetype = 'db';

  dataSPfreq = ft_freqbaseline(cfg, dataSPfreq);

The call to freqstatistics is as follows:

cfg = [];



cfg.method      = 'template';        % using template method

cfg.template    = 'Control_neighb.mat'; % specify type of template

cfg.layout      = 'quickcap64.mat';  % specify layout of sensors

cfg.feedback    = 'yes';             % show a neighbour plot





neighbours      = ft_prepare_neighbours(cfg, MDDSubj_sp_lpfc_freq{1});





cfg.channel = 'all';

cfg.latency = [0.01 1] ;

cfg.frequency = 'all' ;

cfg.parameter = 'powspctrm';



cfg.neighbours          = neighbours; % defined as above

cfg.method              = 'montecarlo';

cfg.statistic           = 'ft_statfun_indepsamplesT';





cfg.correcttail         = 'alpha';

cfg.correctm            = 'cluster';

%cfg.alpha = 0.05

cfg.numrandomization    = 2000;

cfg.minnbchan           = 2;

cfg.spmversion          = 'spm12';

cfg.fsample             = 1000;





Nsub                        = length(ControlsSubj_sp_lpfc_freq) +
length(MDDSubj_sp_lpfc_freq) ;

cfg.design                  = [];

cfg.design(1,1:Nsub)        = [ones(1, length(ControlsSubj_sp_lpfc_freq))
(2*ones(1, length(MDDSubj_sp_lpfc_freq)))];

cfg.ivar                    = 1;



% Resulting Cluster Corrected Permutation test

% !!order of structures must follow that specified in the design matrix!!

MDD_vs_Controls_sp_lpfc_freq_mcc =
ft_freqstatistics(cfg,ControlsSubj_sp_lpfc_freq{:},
MDDSubj_sp_lpfc_freq{:});


It is after calling ft_freqstatistics that I get the error "Could not
determine the parametric critical value for clustering".


Any help would be greatly appreciated.


Thank you,

Paul
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