As should be self-evident, bilateral midline generator configurations, depicted in Fig. 7C and D, are inconsistent with any single dipole inverse solution, and no single dipole can account for the variance of the topography. Solutions based on linked, symmetric bilateral dipoles can represent the orientation of the simulated dipoles, their locations being displaced from the midline according to the regularization parameter (not shown). However, the heuristic value of blindly submitting these topographies to a single-dipole model is to emphasize that ERP fields that match a single, radially-oriented midline dipole are inconsistent with the intracranial currents implied by a deep bilateral midline generator. As indicated in Fig. 8A, no single-dipole localization was possible for the deep bilateral generator (row 1), but the shallow bilateral generator (Fig. 8A, row 2) was localized to the midline (albeit at an implausibly superficial location). Of course, solutions for unilateral, open-field generators, each simulated by a single dipole, closely replicate the orientations and locations of the original simulation (Fig. 8A, rows 3 and 4).
