Non parametric test on coherence

[Matteo Demuru]

Dear Eric,

I have tried the between-trials experiment too, but the two problems still
remain (the statfun_indepsamplesZcoh looks for label field. Furtheremore if
I add it the reshape function crashes). Any other suggestions?

I have also another question relative to your reply: the baseline and
activation trials were already divided in the within-trials experiment, the
only difference with the between-trials experiment are relative to the
configuration parameters (i.e.  in between-trials only cfg.ivar is set while
in within-trials cfg.ivar and cfg.uvar are set) am I wrong?

Regarding the 'label field' problem, it seems a required field for the
configuration struct because it is used in statfun_indepsamplesZcoh to
calculate the channel combinations for the coherence.

Thanks a lot

Matteo



On Wed, Apr 28, 2010 at 9:17 AM, Eric Maris <e.maris at donders.ru.nl> wrote:

>  Dear Matteo,
>
>
>
>
>
> The statfun indepsamplesZcoh can only be used in a between-trials
> experiment. You could cut out your baseline and activation segments
> separately and then compare them in a non-paired fashion.
>
>
>
>
>
> Best,
>
>
>
> Eric
>
>
>
>
>
> *From:* FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] *On
> Behalf Of *Matteo Demuru
> *Sent:* dinsdag 27 april 2010 16:21
> *To:* FIELDTRIP at NIC.SURFNET.NL
> *Subject:* [FIELDTRIP] Non parametric test on coherence
>
>
>
> Dear all,
>
>
>
> I have a problem using freqstatistics to calculate significance for
> coherence.
>
>
>
> Specifically I have a subject and I am performing a within-trials
> experiment using 'indepsamplesZcoh' as statistic.
>
>
>
> I calculate the TFR of my data with the cfg.output='powandcsd' and
> cfg.keeptrials='yes' parameters. Then I call freqstatistics to compare my
> different experimental conditions (baseline vs activation).
>
>
>
> The function crashes with this output:
>
>
>
> ??? Reference to non-existent field 'label'.
>
>
>
> Error in ==> statfun_indepsamplesZcoh at 76
>
>   nchan = length(cfg.label);
>
>
>
> I have tried to add this field to the cfg struct assigning the cell that
> contains the interested channels. However this time I have another error:
>
>
>
> ??? Error using ==> reshape
>
> To RESHAPE the number of elements must not change.
>
>
>
> Error in ==> clusterstat at 178
>
>       posclusobs = findcluster(reshape(postailobs,
> [cfg.dim,1]),channeighbstructmat,cfg.minnbchan);
>
>
>
>
>
> Any suggestions?
>
>
>
> Thanks in advance
>
>
>
> Matteo Demuru
>
>
>
> ----------------------------------
>
> 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.
>
> http://listserv.surfnet.nl/archives/fieldtrip.html
>
> http://www.ru.nl/fcdonders/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.
>
> http://listserv.surfnet.nl/archives/fieldtrip.html
>
> http://www.ru.nl/fcdonders/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.
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