EEG: electric potential 𝑉
𝑉 in the plane of the page (red +, blue −)
MEG: magnetic field 𝐁
𝐁 is perpendicular to the page (red out, blue in)
𝚫𝜃 =
Length (𝑑)
Current (𝐼)
Colour scale
𝑉 (left axis)
𝐵𝑧 (right axis)