[Eeglablist] Three EEGLAB questions

[Giovanni Santostasi]

Here some simple code you could use (independently of EEGlab):

Suppose EEG1 is time series 1 and EEG2 is time series 2, also supposed you
want to compare phase coherence in the delta band (you can change this for
any band you want):

.....

samp_f=500; % sampling frequency
wd=[0.5 4]/(samp_f/2); % filter setting for delta band, 0.5-4 Hz
[b,a]=butter(4,wd); % butter filter
FEEG1=filtfilt(b,a,EEG1); % filtering time series 1
FEEG2=filtfilt(b,a,EEG2); % filtering time series 2
PhaseEEG1=angle(hilbert(FEEG1))+pi;% phase for EEG1
PhaseEEG2=angle(hilbert(FEEG2))+pi;% phase for EEG2

PhasePD=(PhaseEEG1-PhaseEEG2)./PhaseEEG2*100; % percentage difference
% between EEG1 and EEG2 relative to EEG2 phase.


PhasePD would be another time series with same sampling frequency of EEG1
and EEG2 and it would give you a simple measure of the phase coherence
between the two series.

Giovanni




On Sat, Sep 28, 2013 at 9:38 PM, Fred Travis <ftravis at mum.edu> wrote:

>  Thank you Robert.
>
> As you know, there is a growing body of work on synchrony.  How can I
> calculate that in EEGLAB?
>
> Fred
>
>  On 9/27/2013 8:21 PM, robert coben wrote:
>
> Fred and Arnaud,
>
>  Having worked with coherence and more recently sloreta coherence and
> SIFT, I will provide some feedback. Coherence as a measure of
> "connectivity" between pairs is extremely flawed. I would agree with Arnaud
> is recommending SIFT and granger causality. The information is much richer
> and more closely resembles structural connectivity metrics.
>
>  Rob
>
>
>  On Sep 27, 2013, at 5:38 PM, Fred Travis <ftravis at mum.edu> wrote:
>
>  Hi Arnaud
>
> By synchrony I mean in phase EEG.  Coherence us a general case-stability
> of phase relation--and synchrony is a specific case--stability of phase
> relation and in phase
>
> Fred
> On 9/27/2013 2:54 PM, Arnaud Delorme wrote:
>
> Hi Fred,
>
>  what do you mean by synchrony?
> To caclulate some of additional connectivity measures, you might want to
> try SIFT, an EEGLAB associated toolbox and plugin. It will allow you to
> compute Granger Causality based measures such as partial directed
> coherence.  It will also allow you to compute many other measures including
> the popular directed transfer entropy.
>
>  Hope this helps,
>
>  Arno
>
>
>    1. synchrony (rather than coherence)
>
>  2. cross frequency coherence--coherence between frequency bands (Palva
> and Palva)
> 3. cepstrum analysis--frequency analysis of the power spectra
>
> Many thanks
>
> Fred
>
> --
> Fred Travis, Ph.D.
> Director, Center for Brain, Consciousness and Cognition
> Dean, Graduate School
> Chair, Maharishi Vedic Science Department
> Office:  641 472 1209
> Fax: 641 470 1316
> Skype: fredtravis
> Website: drfredtravis.com
>
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>
> --
> Fred Travis, Ph.D.
> Director, Center for Brain, Consciousness and Cognition
> Dean, Graduate School
> Chair, Maharishi Vedic Science Department
> Office:  641 472 1209
> Fax: 641 470 1316
> Skype: fredtravis
> Website: drfredtravis.com
>
>  _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to
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>
>
> --
> Fred Travis, Ph.D.
> Director, Center for Brain, Consciousness and Cognition
> Dean, Graduate School
> Chair, Maharishi Vedic Science Department
> Office:  641 472 1209
> Fax: 641 470 1316
> Skype: fredtravis
> Website: drfredtravis.com
>
>
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