Author response image 5. Granger causality simulation.

Simulation results of an auto-regressive model of a coupled system, where process A is oscillating with 20Hz and process B with 30 Hz, and where A is driving B with a delay of 16.67 ms. When analysing spectral Granger causality, we would expect no GC from A→A, B→A, and B→B. Only A→B should reveal a 20 Hz component. Indeed, this is what we obtained as results by our simulation. Thus, it is well possible to detect Granger causality of signal with a period (50 ms) that is considerably larger than the coupling delay (16.67 ms).