Locations of regional sources determined for the N1, N1c, and P2 are shown in axial (A), coronal (B), and sagittal (C) views superimposed on the average brain of BESA. Source localizations were determined from the grand averaged data and are shown for the condition in which hemispheric symmetry was imposed. D, Orientation and strength (dipole moment) of each source are shown in a three-dimensional view (resultant vectors for the N1 and P2, radial vector for the N1c, tails negative). Dipole moments are proportional to one another (maximum, 48.6nAm; P2 source, lef the misphere). E, Coordinate system. Ant-Pos, Anteroposterior; Inf-Sup, inferior-superior; Med-Lat, mediolateral.