[FieldTrip] statistics test on PLV of connectivity

[jan-mathijs schoffelen]

Hi Jun,

If you want to test whether within a subject the PLV across conditions is significantly different (in some statistical sense), you would either do a statistical test along the lines described in "Nonparametric statistical testing of coherence differences, E Maris, JM Schoffelen, P Fries, Journal of neuroscience methods 163 (1), 161-175" or "Comparing spectra and coherences for groups of unequal size, H Bokil, K Purpura, JM Schoffelen, D Thomson, P Mitra, Journal of neuroscience methods 159 (2), 337-345". 

This functionality is not supported in ft_connectivityanalysis. For the former way of statistical testing, you should use ft_freqstatistics, in combination with an adjusted version of statfun_indepsamplesZcoh in order for it to compute differential PLV, rather than Z-transformed coherence difference. Alternatively, you could ask ft_connectivity to compute a jackknife estimate of the variance of the PLV, which could be used in a traditional t-test.

Best,

Jan-Mathijs


On Jan 12, 2013, at 1:22 AM, Jun Wang wrote:

> Dear fieldtrip experts,
>    I have a question regarding to test the plv output from ft_connectivityanalysis. How can I  check the significance with a statistical test based on surrogate data. the plv output didn't have the magnitude for single trials.
> 
> thanks
> Jun 
> _______________________________________________
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> fieldtrip at donders.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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