PLV Connectivity on source

7

Hi

I had question about how connectivity measures are calculated at the source level. There are a lot of discussions already on this topic and I thought it better to add to an existing one.

Specifically, I was wondering how these measures (PLV, PTE, etc) are calculated when the option to apply the scout function "After" is selected using a 1xN analysis. My understanding of the pipeline is as follows:

  1. The Hilbert (or other) time-frequency transform is applied to data in each vertex within both scouts
  2. A mean connectivity value for each vertex in scout A is determined (the average connectivity between a vertex in scout A and each vertex in scout B)
  3. The mean (or PCA etc) of these connectivity value within scout A is reported

I assume this is different from the "Before" selection which computes the mean (or PCA etc) activity across the scout first and then applies the transformation and connectivity analysis on this single signal. Is this the correct description of these processes?

Thanks in advance.