[Eeglablist] Why is Phase Coherence Greater than 1?

[Makoto Miyakoshi]

Thanks Arnon for the deteiled report.
Ramon, do you think this is related to the bootstrap issue again?

Makoto


On Thu, Jul 24, 2014 at 10:22 AM, Arnon Yang <abarnyeu at hotmail.com> wrote:

> Hi Makoto,
>
> Thanks for the quick reply.
>
> The steps I took were this:
> 1. Import Netstation binary file into EEGLab.  (The file has only 1 epoch
> and filters and ICA have not been ran yet.)
> 2. Plot -> Time-frequency -> Cross-coherence pop_newcrossf()
> 3. I compared channels 1 and 2, in an epoch range 100 ms after the start
> and 100 ms before the end.  Log scale for frequencies was set and phase
> coherence was used.  Bootstrap significance level was set to default and
> 'padratio' = 1.
> 4. From the output diagram, phase coherence reaches values as high as 1.3
> e+007, as shown by the color side bar on the upper panel.
>
> I've attached screenshots of pop_newcrossf() and the resulting figure.
>
> Thanks very much, Makoto.
>
> Arnon
>
>
>
> ------------------------------
> From: mmiyakoshi at ucsd.edu
> Date: Thu, 24 Jul 2014 10:01:38 -0700
> Subject: Re: [Eeglablist] Why is Phase Coherence Greater than 1?
> To: abarnyeu at hotmail.com; nucleuscub at gmail.com
> CC: eeglablist at sccn.ucsd.edu
>
>
> Dear Arnon,
>
> Thanks for reporting it. Please describe how to replicate it in our
> environment so that we can work on it. Thank you for your cooperation.
>
> Makoto
>
>
> On Wed, Jul 23, 2014 at 11:12 AM, Mister Arnold <abarnyeu at hotmail.com>
> wrote:
>
> Hi all,
>
> I have been trying to compare the phase coherence (phase locking value) of
> 2 channels of the same data set.
>
> From my understanding, coherence should always be a value between 0 and
> 1.  However, when I use the pop_newcrossf() function to plot the coherence,
> I obtain values which are as large as 1.30 e+007.
>
> Is this expected and how can I change it back to a value that is between 0
> and 1?
>
> Any suggestions is appreciated.  Thanks very much.
>
> Arnon
>
>
>
>
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>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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