[Mne_analysis] Negative Weighted Phase Lag Index Values

[Eric Larson]

Yes it looks like WPLI should be bounded by 0 and 1. Can you open an MNE
issue so we can look into it further?

Eric


On Wed, Jun 14, 2017 at 1:28 PM, Stout, Jeffrey <jstout at mcw.edu> wrote:

> We are running analyses on resting state MEG data and we are finding
> negative values in the weighted phase lag index (wpli) measure.  We have
> also run this data using the phase lag index (PLI) measure and do not see
> any values below zero.  I thought that both the PLI and WPLI should be
> defined from 0 to 1.  Although the negative values tend to be small, we are
> seeing this across many subjects.
>
>
>
> wpli=np.load('connmat_wpli2_debiased13_30hz_run1.npy')
>
>
>
> np.min(wpli), np.max(wpli)
>
> Out[22]: (-0.0048496421426467845, 0.14954351856205442)     <<<<<<<<< WPLI
> minimum value below Zero
>
>
>
> pli=np.load('connmat_pli13_30hz_run1.npy')
>
>
>
> np.min(pli), np.max(pli)
>
> Out[24]: (0.0, 0.21375066880684856) <<<<<<<<< PLI minimum value equals zero
>
>
>
>
>
> Is this a correct finding?  Any insight would be helpful.
>
>
>
>
>
> Thank you,
>
> Jeff Stout
>
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