[FieldTrip] Coherency parameters

[jan-mathijs schoffelen]

Hi Casper,

The approach I would take depends on your question.

If you want to test for coherence differences within a subject, your unit of observation is a trial, so the permutation test shuffles the trials between the experimental condition. In this instance you can use statfun_indepsamplesZcoh (with fourier-data in the input (i.e. cfg.output = 'fourier' when calling ft_freqanalysis).

If you want to test across subjects, your unit of observation is a subject, so there you can compute the coherence per subject and condition and then do the statistical test by shuffling the conditions. This has for example been done in the following paper: J Neuroscience 2011, 31(18): 6750-6758; doi: 10.1523/​JNEUROSCI.4882-10.2011


Best

Jan-Mathijs

On May 29, 2012, at 9:44 AM, Casper van Heck wrote:

> Dear Fieldtrip users,
> 
> I'm currently working on coherency between EEG and EMG, so far without any significant problems. However, I'd like to get statistical significancy (in the hope that's possible) tested on my coherency-data.
> In the Fieldtrip reference there's a mention of something resembling statistics in combination with coherency (in the help of the 'STATISTICS_MONTECARLO' function), but I've not found how to call this function.
> 
> My question is: is there a standard method to perform statistical analysis on coherency data?
> 
> Sincerely,
> 
> Casper van Heck (Intern)
> Clinical Neurophysiology, UMC St. Radboud, Nijmegen
> _______________________________________________
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> fieldtrip at science.ru.nl
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Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

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