improvements for the CSD techniques have been very rare and slow. One obvious exception to this limitation is the work by Kayser, Tenke and Colleagues, who have innovated some methods, for example, to extract PCA components of the CSD (Kayser and Tenke, 2003; Tenke and Kayser, 2005) and successfully implemented this approach to study clinical domains (Kayser et al., 2006, 2009, 2010a,b,c, 2012, 2013, 2014; Tenke et al., 2008, 2010, 2011). Other concerns of CSD are related to its methodological limitations, which may be addressed by future studies: 1) the transformation of the EEG potentials into the CSD leads to a partial data loss, since the low-spatial-frequency (LSF) components are attenuated (Hjorth, 1980; cf. Ponomarev et al., 2014), although it can be argued that it amounts to ‘data loss’ only if the attenuated/removed LSF contains ‘neural signal’ rather than volume conduction effects; 2) the requirement of an adequate number of scalp electrodes (32 electrodes or above) for reliable computation of CSD (Pizzagalli, 2007), although helpful CSD topography has been obtained from 19 scalp electrodes (Harmony et al., 1993; Fernandez-Bouzas et al., 1995, 1997; Ponomarev et al., 2014) or even less (Turetsky et al., 1998a, 1998b, 2000); and 3) it is
