[FieldTrip] ROC_based permutation test

Shen-Mou Hsu explena at gmail.com
Tue Jun 11 09:48:34 CEST 2013

Dear all,

I was trying to perform signle-trial ROC-based permutation tests using the
statfun_roc. However I encountered two questions and wondered if anyone
could kindly shed some light on the issues. First, is it necessary to
perform baseline normalization for each trial before the tests? Second, an
error message returned stating "Error using roc. Too many input arguments.
Error using ft_statistics_montecarlo (line 223) could not determine the
parametric critical value for clustering", after running the following

load (['t_RF_EpoRejDePow']); load (['t_RN_EpoRejDePow']);

cfg = [];
cfg.channel     = 'MEG';
cfg.latency     = [-0.35 0.55];
cfg.frequency   = [8 12];
cfg.parameter   = 'powspctrm';
cfg.method      = 'montecarlo';
cfg.statistic   = 'roc';
cfg.alpha       = 0.025;
cfg.tail = 0;
cfg.correctm    = 'cluster';
cfg.clusteralpha = 0.05;
% cfg.correcttail = 'prob';
cfg.clustertail = 0;
cfg.numrandomization = 1000;
cfg.minnbchan        = 2;
cfg_neighb.method    = 'distance';
cfg.neighbours       = ft_prepare_neighbours(cfg_neighb, t_RN_EpoRejDePow);
cfg.logtransform = 'yes';

design = [1*ones(1,size(t_RF_EpoRejDePow.powspctrm,1))
2*ones(1,size(t_RN_EpoRejDePow.powspctrm,1))]; % the first dimension of
these variable is the trial number.
cfg.design  = design;

P_ROC_t_RFvsRN = ft_freqstatistics(cfg,t_RF_EpoRejDePow,t_RN_EpoRejDePow);

Any help is greatly appreciated.

Best regards,

Shen-Mou Hsu
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