An axial view of the cortically-generated magnetic field of a human listener, measured using whole-head magnetoencephalography (MEG), at a single moment in time. The Isofield contours in red indicate the strength of outward magnetic flux. Blue contours indicate the strength of inward magnetic flux. The digitized scalp surface is grey. For each hemisphere, a magnetic dipole-like pattern is centered over temporal cortex, and the neural generator itself, located in planum temporale, is an inferiorly flowing neuronal electric current. The MEG channels responding more strongly in the center of each flux area are designated by filled yellow circles.