[Eeglablist] outputs for newcrossf

[Arnaud Delorme]

Dear Ana,

you may want to check out our the EEGLAB reference article

http://sccn.ucsd.edu/~arno/mypapers/DelormeEEGLAB2004.pdf

it contains a description of how the coherence is calculated.
Best,

Arno

On 18 Sep 2012, at 17:30, Makoto Miyakoshi wrote:

> Dear Ana,
> 
> In the crosstimef help,
> 
> % coh = Matrix (nfreqs,timesout) of coherence magnitudes
> 
> Wikipedia says that magnitude is by definition length of a vector, so
> the value must be scalar.
> 
> allcoher on the other hand is a raw phase measures before calculating
> coherence between a paired channels/ICs, so it should be complex.
> 
> This makes sense to me. What do you think?
> 
> Makoto
> 
> 2012/9/17 Ana Navarro Cebrian <sabato45 at hotmail.com>:
>> Hi Makoto,
>> coh(1,1)
>> 0.2780
>> 
>> for allcoher I get complex numbers (so I imagine I can obtain both,
>> amplitude and phase from it?):
>> allcoher(1,1,1)
>> -1.0320e+05 +3.4039e+03i
>> 
>> Thanks,
>> Ana
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>>> From: mmiyakoshi at ucsd.edu
>>> Date: Mon, 17 Sep 2012 18:45:06 -0700
>>> Subject: Re: [Eeglablist] outputs for newcrossf
>>> To: sabato45 at hotmail.com
>>> CC: eeglablist at sccn.ucsd.edu
>> 
>>> 
>>> Dear Ana,
>>> 
>>> Could you tell me the first 2 or 3 values of coh/allcoher you get from
>>> the calculation?
>>> 
>>> Makoto
>>> 
>>> 2012/9/16 Ana Navarro Cebrian <sabato45 at hotmail.com>:
>>>> Hi everybody,
>>>> I'm using newcrossf to calculate the coherence between two channels and
>>>> it's
>>>> not clear to me what exactly the outputs coh, cohangle and allcoher are.
>>>> I'm trying to compute Phase Coherence ('type', phasecoher), but the
>>>> output I
>>>> obtain in coh (as well as allcoher) still seems to me to be referring to
>>>> Amplitude and not Phase. Does anybody know if that's true? In the
>>>> documentation they are explained as coherence amplitude and single trial
>>>> coherence.
>>>> On the other hand, I understand that the output cohangle gives me the
>>>> values
>>>> for phase coherence.
>>>> Thank you,
>>>> ana
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
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>>> 
>>> 
>>> 
>>> --
>>> Makoto Miyakoshi
>>> JSPS Postdoctral Fellow for Research Abroad
>>> Swartz Center for Computational Neuroscience
>>> Institute for Neural Computation, University of California San Diego
> 
> 
> 
> -- 
> Makoto Miyakoshi
> JSPS Postdoctral Fellow for Research Abroad
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
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