Contributions of AC fields (\(\bf A\)) and AC areas (\(\bf B\)) to the overall MEG signal. The response magnitudes systematically decrease from core to belt to parabelt fields (A). However, the larger number of belt fields (eight, compared to three core fields) compensates for this disparity such that the areal contributions of core and belt to the MEG signal are almost balanced (B). The magnitude of the parabelt response to the MEG signal is apparently much weaker, but it still adds to the observed shift in the M100 peak latency.