Nunez and Srinivasan (2006, 2014) have repeatedly emphasized that scalp EEG measures exhibit distinct dynamics at different spatial scales, concluding that unprocessed surface potentials and SL estimates (high resolution EEG) provide complementary information about neocortical dynamics. Whereas ERP components are rather confined in spatial scale, with P3b probably revealing the broadest scalp distribution, synchronized oscillations may be present on a larger spatial scale, involving rhythmic activations of anterior and posterior regions, which will be suppressed (i.e., spatially filtered) by SL estimates based on flexible splines (Nunez and Srinivasan, 2014). For example, Srinivasan (1999) reported that the spatial structure of alpha rhythm coherence differs between adults and children due to the endogenesis of maturing brain tissue, with overall large-scale (> 20 cm) cortical dynamics in adults insufficiently represented by flexible spline SL estimates. Consequently, functional connectivity and coherence measures based on SL estimates that only represent a smaller spatial scale (i.e., less than 5 cm) will not be able to detect these long-range oscillations. However, simulations of broadly-distributed sine and cosine generator sources indicated superior representations of amplitude and phase for
