'Bivariate Granger Causality(spectral)NxN' in Connectivity

[Sylvain]

@Francois

Secondly, wether any models like multi-variant autoregressive models or not are used in Granger Causality?
Thirdly, when using the Granger Causality to analyse the connectivity between two channels, which time scope is recommeded under the different sampling rate?

I am not sure about what you mean exactly. I recommend you use parameters that have been published in journal articles and reporting on using Granger measures.