splines (i.e., m = 2 or m = 3; Babiloni et al., 1995), the recommendation to use the surface Laplacian as a supplement to surface potential analysis implies an even greater discrepancy by prioritizing reference-dependent topographies without regard for the impact of volume conduction. Surface Laplacian estimates obtained with less flexible spherical splines operate on a spatial scale (i.e., intermediate for m = 4) that is not only suitable for low-density EEG recordings but also appears to be quite useful for high-density EEG (Kayser and Tenke, 2006b; Tenke and Kayser, 2012). Of course, less flexible splines come with the costs of giving up on sharpening EEG topographies, one of the embraced advantages of the surface Laplacian, but this impediment also applies to surface potentials.
