Is Granger causality analysis a linear operation？

[Francois]

@NingZhuang

(1) The correct calculation method should be as follows: Granger connection is computed for each trial, and the average Granger connection matrix under the experimental conditions is obtained by averaging all trial connection matrices. Am I right?

I wonder if it is not better to concatenate all the signals first and then compute the GC, as available directly in the options of the GC process in Brainstorm.

@hossein27en?

(2) In addition, for Granger causality analysis, is the length of stimulation signal of 5S long enough (equal to the length of ERP)?
(3) If the length of 5S is too short for Granger connection analysis, is it impossible to use Granger analysis method? Is there any time requirement for other connection methods?

I don't know...
@hossein27en?