Freqstatistics Yields Zero Significant Clusters?

[Eric Maris]

Hi Charles,



Although I'm not 100 percent sure that this is the cause of your problems,
the way you specify the unit of observation is definitely wrong. You have 22
units of observations (i.c., subjects) so the first row of cfg.design must
be [1 2 ... 22; ... ]

Also, did you check whether cfg.design is a 2-by-22 array? In the lines
below, a semicolon seems to be missing.

> cfg.design           = [1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11  %
> subject number is 1-11 males and 1-11 females
>                         1 1 1 1 1 1 1 1 1 1  1  2 2 2 2 2 2 2 2 2 2  2]; %
> condition number with 1 being males and 2 being females
>
> cfg.uvar = 1;                                   % "subject" is unit of
> observation
> cfg.ivar = 2;                                   % "condition" is the
> independent variable


Good luck,


dr. Eric Maris
Donders Institute for Brain, Cognition and Behavior
Center for Cognition and F.C. Donders Center for Cognitive Neuroimaging
Radboud University
P.O. Box 9104
6500 HE Nijmegen
The Netherlands
T:+31 24 3612651
F:+31 24 3616066
E: e.maris at donders.ru.nl

MSc Cognitive Neuroscience: www.ru.nl/master/cns/


> [stat] = freqstatistics(cfg, maleloc_all, femloc_all);
>
> cfg = [];
> [freq_maleloc] = freqdescriptives(cfg, maleloc_all);
> [freq_femloc]  = freqdescriptives(cfg, femloc_all);
>
> cfg = [];
> cfg.zlim = [-6 6];
> cfg.alpha = 0.025;
> clusterplot(cfg, stat);
>
> --------------------------------
> Reading time-frequency representation using BESA toolbox
> 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 31 time bins
> selected 79 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 at 194
> 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 11 levels
> number of repeated measurements in each level is 2 2 2 2 2 2 2 2 2 2 2
> computing statistic
> estimated time per randomization is 1 seconds
> computing statistic 1 from 100
> .
> ..
> computing statistic 100 from 100
> performing Bonferoni correction for multiple comparisons
> the returned probabilities are uncorrected, the thresholded mask is
corrected
> the input is freq data with 81 channels, 79 frequencybins and 31 timebins
>
> computing the leave-one-out averages [---|
]
> computing the leave-one-out averages [-------/
]
> computing the leave-one-out averages [-----------
]
> computing the leave-one-out averages [-------------\
]
> computing the leave-one-out averages [----------------|
]
> computing the leave-one-out averages [--------------------/
]
> computing the leave-one-out averages [------------------------
]
> computing the leave-one-out averages [--------------------------\
]
> computing the leave-one-out averages [-----------------------------|
]
> computing the leave-one-out averages [---------------------------------/
]
> computing the leave-one-out averages
[-------------------------------------]
> the input is freq data with 81 channels, 79 frequencybins and 31 timebins
>
> computing the leave-one-out averages [---|
]
> computing the leave-one-out averages [-------/
]
> computing the leave-one-out averages [-----------
]
> computing the leave-one-out averages [-------------\
]
> computing the leave-one-out averages [----------------|
]
> computing the leave-one-out averages [--------------------/
]
> computing the leave-one-out averages [------------------------
]
> computing the leave-one-out averages [--------------------------\
]
> computing the leave-one-out averages [-----------------------------|
]
> computing the leave-one-out averages [---------------------------------/
]
> computing the leave-one-out averages
[-------------------------------------]
> no significant clusters in data; nothing to plot
> >>
>
> ----------------------------------
> The aim of this list is to facilitate the discussion between users of the
FieldTrip
> toolbox, to share experiences and to discuss new ideas for MEG and EEG
analysis.
> See also http://listserv.surfnet.nl/archives/fieldtrip.html and
> http://www.ru.nl/neuroimaging/fieldtrip.

----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.