[Mne_analysis] MNE and EEG channel synchrony

[Hari Bharadwaj]

Hi Theodore,
    It looks Iike the PLV measure computed in the paper you cite is looking for the stability of the phase difference **across time samples** within 5 second epochs (and looks at how this synchrony evolves over epochs/frames) as in the reference below (noting it for the benefit of others on the list)... 

I don't think this variety of PLV is implemented in mne-python... Perhaps some others on the list might be able to verify if that is indeed unfortunately the case.. It may be possible to extend cwt_morlet or similar from the time-frequency module to make a custom function to do what you are interested in. 


HTH,
Hari 

Ref:
Le Van Quyen, M., Foucher, J., Lachaux, J. P., Rodriguez, E., Lutz, A., Martinerie, J., & Varela, F. J. (2001). Comparison of Hilbert transform and wavelet methods for the analysis of neuronal synchrony. Journal of neuroscience methods, 111(2), 83-98.


> On Oct 14, 2014, at 3:44 AM, Theodore Vasiloudis <theodoros.vasiloudis at gmail.com> wrote:
> 
> Hello Hari,
> 
> What I'm trying to do is recreate the techniques used in [1] for with the purpose of
> EEG classification. 
> More specifically I would like to compute some of the Wavelet-based synchrony 
> measures shown in Appendix A.4.
> 
> There the authors do not try to extract epochs from the data but rather extract 5 second
> segments from the multichannel EEG signal, compute the phase for each channel in every frame ,
> and use that in order to compute the statistics on the differences of phase between
> channels for the same segment.
> 
> [1] Classification of patterns of EEG synchronization for seizure prediction
> 
> 
> 
>> 
>> Hi Theodore,
>> 
>> Most connectivity metrics are based on some sort of consistency of the
>> phase relationship between two signals across epochs/trials... In your
>> example, the PLV looks for how repeatable the phase difference between two
>> channels across epochs/trials...
>>   Thus you may want to consider in what sense you want to compute
>> synchrony and what that would mean before attempting to use the
>> spectral_connectivity(.) capabilities of MNE.
>> 
>> HTH,
>> Hari
> 
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