[Mne_analysis] PLV in label in source space

[Ghuman, Avniel]

Dear Laetitia,

Generally I find that spatially averaging across the label, then calculating the PLV works better.

Best wishes,
Avniel

From: Laetitia Grabot <laetitia.grabot at gmail.com<mailto:laetitia.grabot at gmail.com>>
Reply-To: Discussion and support forum for the users of MNE Software <mne_analysis at nmr.mgh.harvard.edu<mailto:mne_analysis at nmr.mgh.harvard.edu>>
Date: Friday, September 19, 2014 10:27 AM
To: "mne_analysis at nmr.mgh.harvard.edu<mailto:mne_analysis at nmr.mgh.harvard.edu>" <mne_analysis at nmr.mgh.harvard.edu<mailto:mne_analysis at nmr.mgh.harvard.edu>>
Subject: [Mne_analysis] PLV in label in source space

Dear all,

When calculating the phase-locking value (PLV) from n trials in a label in source space, I'm wondering if it is more relevant to:
- spatially averaging the trials across the label, then calculated the PLV.
- calculating the PLV on each source then averaging the PLVs across the label.

I compared the two methods, and things change a lot (the PLV is larger when the average is done at the level of the trials than when it's done at the level of the PLVs). I would have the feeling that averaging the trials first is more relevant, especially if using svd, so that the averaged signal is more robust. Could someone confirm/contradict my feeling?

Thanks in advance,
Laetitia G.