Partial Directed Coherence

[Ivana Konvalinka]

Thanks Jan-Mathijs, that makes sense.

One more question - is it possible to just do partial coherence in
fieldtrip?

Best wishes,

Ivana



On Tue, Nov 9, 2010 at 11:54 AM, jan-mathijs schoffelen <
jan.schoffelen at donders.ru.nl> wrote:

> Dear Ivana,
>
> There is not so much information on the fieldtrip wiki as of yet. But I am
> working on it.
> For the time being, perhaps you know that in order to compute partial
> directed coherence, you need to first fit an autoregressive model to your
> time domain data. This is necessary to obtain a thing which is known as the
> spectral transfer function, from which PDC will be derived.
> Therefore you need to do two things before you can call
> ft_connectivityanalysis:
>
> use ft_mvaranalysis to obtain the MVAR-model of your data.
> use ft_freqanalysis (cfg.method = 'mvar') to obtain the spectral transfer
> function.
>
> Note that you do not need to specify partchannel when you will be computing
> pdc; the idea is that by fitting a multivariate model to all channels of
> interest, the 'partialisation' is achieved. At least that's the theory...
>
> I hope to find time to work on the documentation soon.
>
> Best wishes,
>
> Jan-Mathijs
>
>
> On Nov 9, 2010, at 11:36 AM, Ivana Konvalinka wrote:
>
> Hello,
>
> I was wondering if it would be possible to get more information on partial
> directed coherence, using ft_connectivityanalysis. I've been trying to set
> it up on the frequency data of pairs of EEG electrodes, by partialling out
> motor evoked fields.
>
> Hence, something like this:
> cfg.method = 'pdc';
> cfg.channelcmb = { pairs of electrodes here };
> cfg.partchannel = { electrodes containing fourier spectra of motor events
> };
>
> pdc1 = ft_connectivityanalysis(cfg, freqs);
>
> I get the following error: "reference to non-existent field 'transfer'".
>
> Is there any more documentation on this method in fieldtrip?
>
> Thanks in advance!
>
> Ivana
>
>
> --
> Ivana Konvalinka
> PhD Student
> Interacting Minds Group
> Center of Functionally Integrative Neuroscience
> University of Aarhus
> Denmark
>
> http://www.interacting-minds.net
> http://www.cfin.au.dk
>
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> See also http://listserv.surfnet.nl/archives/fieldtrip.html
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> ---------------------------------------------------------------------------
>
>
> Dr. J.M. (Jan-Mathijs) Schoffelen
> Donders Institute for Brain, Cognition and Behaviour,
> Centre for Cognitive Neuroimaging,
> Radboud University Nijmegen, The Netherlands
> J.Schoffelen at donders.ru.nl
> Telephone: 0031-24-3614793
>
> ---------------------------------------------------------------------------
> You are receiving this message because you are subscribed to
> the FieldTrip list. 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.
> ---------------------------------------------------------------------------
>



--
Ivana Konvalinka
PhD Student
Interacting Minds Group
Center of Functionally Integrative Neuroscience
University of Aarhus
Denmark

http://www.interacting-minds.net
http://www.cfin.au.dk

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and http://www.ru.nl/neuroimaging/fieldtrip.
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