[FieldTrip] Nonparametric statistical testing of phase coherence

Eric Maris e.maris at psych.ru.nl
Tue Apr 9 12:09:03 CEST 2013

Hi Ana,


To compare coherence between conditions across subjects (instead of
trials), you need a different statfun: depsamplesT (for a within-subjects
design; subjects have participated in all conditions) or indepsamplesT
(for a between-subjects design; subjects have participated in only one
condition). Typically, this type of test is performed using power as the
dependent variable, but exactly the same test is used for comparing
coherence in a multiple-subject study. However, you will have to specify
the cfg.parameter field when calling ft_freqstatistics such that it points
to the data field that contains your coherence data (importantly, for a
given reference channel).


Good luck,


Eric Maris 


From: Ana Navarro Cebrian [mailto:sabato45 at hotmail.com] 
Sent: vrijdag 5 april 2013 23:56
To: fieldtrip at science.ru.nl
Subject: [FieldTrip] Nonparametric statistical testing of phase coherence


Hello everybody,

I'd like to use the test proposed in Maris et al., 2007 (that I believe is
implemented in statistics_montecarlo.m?). 

I'm calculating the difference in phase coherence between two conditions.
The problem is that one condition has much less trials than the other, so
I imagine the Montecarlo simulation would need to be across trials, in
which case, I'd end up with a p-value for each individual subject, right?
I'm not sure then how to apply this across subjects. The Maris et al.
paper is very clear, but it only explains single subject analysis. 

I hope that makes any sense. I appreciate any help.



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