[FieldTrip] Connectivity comparison across conditions

[Schoffelen, J.M. (Jan Mathijs)]

Hi Jose,

1.
I want to perform this analysis intra-subject.
I have a plv value for the elctrode combination 1&2 at 30Hz for condition 1, and another value for condition 2 (they both have 80 trials)
Not sure I understand what you mean by permuting the trial labels and what I would do with the obtained values.

See:

Maris E., Schoffelen J.M., Fries P.Nonparametric statistical testing of coherence differences.<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17395267> J Neurosci Methods. 2007 Jun 15;163(1):161-75.

2.
Also, is it not possible to do this along time?

Yes, in principle one could compute a time-resolved PLV. This should be done with cfg.method = ‘mtmconvol’, in ft_freqanalysis.

Jan-Mathijs




On Thu, Jul 9, 2015 at 10:33 AM, Schoffelen, J.M. (Jan Mathijs) <jan.schoffelen at donders.ru.nl<mailto:jan.schoffelen at donders.ru.nl>> wrote:
Hi Jose,

I can think of one out of 2 things:
-you formulate a null hypothesis pertaining to a group of subjects, and do statistical inference across subjects (e.g. by permuting the condition labels), or
-you formulate a null hypothesis pertaining to the observations belonging to the individual conditions, and do statistical inference across observations, e.g. by permuting the trial labels.

Best wishes,
Jan-Mathijs



Jan-Mathijs Schoffelen, MD PhD, Senior researcher

Max Planck Institute for Psycholinguistics
Donders Centre for Cognitive Neuroimaging

E-mail: j.schoffelen at donders.ru.nl<mailto:j.schoffelen at donders.ru.nl>
Telephone: +31-24-3614793<tel:%2B31-24-3614793>

http://www.hettaligebrein.nl<http://www.hettaligebrein.nl/>
http://www.fieldtriptoolbox.org<http://www.fieldtriptoolbox.org/>




On Jul 9, 2015, at 11:24 AM, Jose Rebola <jrebola at gmail.com<mailto:jrebola at gmail.com>> wrote:

Hi,

Is there a straightforward way to compare any connectivity measure at a given frequency (say, plv at 30Hz between electrodes 1 and 2) across conditions? I end up with one value per channel combination per frequency per condition, so what is the right way to compare?

Thanks in advance,

Jose Rebola
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