[FieldTrip] coherence vs magnitude squared coherence

Vries, I.E.J. de i.e.j.de.vries at student.vu.nl
Tue Feb 18 13:31:41 CET 2014


haha no worries, thanks for the reply!
________________________________
From: fieldtrip-bounces at science.ru.nl [fieldtrip-bounces at science.ru.nl] on behalf of jan-mathijs schoffelen [jan.schoffelen at donders.ru.nl]
Sent: 18 February 2014 6:57
To: FieldTrip discussion list
Subject: Re: [FieldTrip] coherence vs magnitude squared coherence

Hi Ingmar,
Sorry for the mix up. Apparently I was not yet fully awake when typing my previous reply. Blame it on the offspring, which kept me awake during some crucial parts of the night: where I typed 'Floris', I of course meant to type 'Ingmar' ;-). To all Florises on the list: this was a free answer to a question you didn't know you wanted to ask.

Best,
Jan-Mathijs

On Feb 18, 2014, at 6:43 AM, jan-mathijs schoffelen wrote:

Hi Floris,
Yes, if you want magnitude squared coherence, you need to square the value fieldtrip computes for you. Note that there is no single convention in the literature: some people report coherence, some report coherence squared.

Best,
Jan-Mathijs

On Feb 18, 2014, at 12:00 AM, Vries, I.E.J. de wrote:

Hi Fieldtrippers,

If I got it correctly, if you choose to calculate coherence (cfg.method='coh') with ft_connectivityanalysis, and you choose cfg.complex='abs' (which is the default), you get the absolute value of coherency, i.e. coherence. But not yet the magnitude squared coherence, which is usually reported in the literature for coherence. So all I need to do is square the coherence value calculated by Fieldtrip right?

Cheers,
Ingmar
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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<mailto:J.Schoffelen at donders.ru.nl>
Telephone: +31-24-3614793

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

_______________________________________________
fieldtrip mailing list
fieldtrip at donders.ru.nl<mailto:fieldtrip at donders.ru.nl>
http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

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

http://www.hettaligebrein.nl

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