In contrast to dipole-based inverse models, sLORETA (Pascual-Marqui et al., 1994) solutions are based on a low-resolution model, in which a concurrence of local activity (i.e., smoothed current density) is presumed. As such, regional generators are not overresolved. To the contrary, unilateral dipoles are blurred (Fig. 8B, rows 3 and 4). Consequently, the structure of the proposed midline closed field generator is fundamentally inconsistent with the presuppositions of this inverse method. However, even after the reduction or elimination of regularization (smoothing), closed fields generators (both superficial and deep) are localized to the dorsal cortical surface (Fig. 8B, rows 1 and 2), with displacements from the midline that coarsely parallel those the sinks of the surface seen for the corresponding CSD solutions (Fig. 7G). Despite the markedly divergent anatomical inferences that might be drawn from the two approaches, sLORETA and surface Laplacian solutions were again (cf. Fig. 5) compatible, thereby supporting the use of such inverses as a deblurring method (Cincotti et al., 2004). The advantage of the surface Laplacian is its generality, in that it is unencumbered by the presuppositions of any particular source model.
