Concatenating coherence matrices

PTE: How is the connectivity matrix stored?
How the Corr matix is saved? - #2 by Francois

I understand this is the upper triangular part, however, why are there 30 frequency components?

This is combined result of the options you selected and the sampling frequency of your signals:

  • frequency resolution: defines the duration of the estimator window used for the FFT,
  • highest frequency of interest: cuts anything above a given threshold after computation for display purposes)

I see now the image displayed in brainstorm is the first frequency component.

You have a slider in the brainstorm window to see the other frequencies

I only want to find coherence in alpha band. Do I average in the 2Hz frequency bins corresponding to alpha 8-12Hz?

Yes, you can do this with the process "Frequency > Group in time of frequency bands" or "Extract > Extract values".