Coherence NxN configuration

  1. "Save individual results..." This option will compute one estimation of MSC for each epoch, using the data only for that epoch, using N windows (N depend on the window length and percentage of overlap). This option can be used to evaluate any change in coherence across epochs.

  2. "Average cross-spectra..." This option will compute one estimation of MSC for all the epochs, using the data from all the epochs, using N windows × number-of-epochs, thus it is a better estimation of MSC.

:bulb: The average of MSC results from Option1 are not the same as the MSC obtained with Option 2 as MSC is not linear.

The Coherence NxN [2021] processes uses the Fourier transform to compute the PSD and cross-spectrum, to later compute MSC. Thus, MSC has the same resolution than FT. To obtain MSC in a band range, a different approach can be take, by filtering data and using Hilbert transform to compute the T-F representation and compute the PSD and cross-spectrum from that T-F representation. More information on these differences here: Lagged coherence - #3 by Raymundo.Cassani

In a not-too-far update, the coherence process GUI will be updated to include both (Fourier transform and Hilbert (or wavelet) transform) approaches

Yes, with the process Frequency > Group in time or frequency bands

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