Statistical tests for connectivity measures

It’s more a methods and mathematical question rather than a pure software question.

I have one participant with about 500x 2 second epochs of EEG data with 64channels in two difference sessions, let’s call them PRE and POST. I also have a 1 minute rest measurement for each session

I want to perform inverse connectivity measurements in the alpha range. For that I use the baseline measurement as noise covariance matrix (and use /fsaverage/bem/fsaverage-ico-5-src.fif)

My issue is that if I use spectral_connectivity_epochs with wpli method I only get 1 value for PRE and 1 value for POST. I could not find any mean to assess the significance of each and every comparison in the dimension 2 connectivity matrix.

Therefore i used spectral_connectivity_time on each epoch, providing me a dimension 3 connectivity matrix. By running a z-test (left skewed distribution), and p-value correction for multiple comparisons I was able to check for significance between surface areas.

I would like to ask whether splitting trials in 2 second epochs, then individually assess connectivity is a correct method to go or whether there are underlying issues with the method used.

unfortunately we don’t have good support yet for estimating statistical significance of connectivity structures. There are discussions / efforts underway to do this, e.g.

and you might also want to check out GitHub - microsoft/graspologic: Python package for graph statistics to see if it fits your use case.

cc @adam2392 in case you have more to add.

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