Laplacian maps corresponding to P3 showed greater radial current flow over right than over left central regions in control participants and in patients with low anhedonia, suggesting that depression (with low anhedonia) may be associated with hemispheric asymmetry during auditory processing. Using the spatial CSD-PCA method, Tenke et al. (2008) examined ERP waveforms from tonal and phonetic oddball tasks in a group of unmedicated depressed patients and found that the patients showed reductions in P3 source for both targets and nontargets, more prominently at lateral sites of the left hemisphere. In another study, Tenke et al. (2010) improved on the prior ERP findings reported during a novelty oddball paradigm in depression (Bruder et al., 2009) by discovering a new novelty component, termed novelty vertex source (NVS), which contributes to the frequently-described frontal P3a. They reported that depressed patients, in comparison to healthy controls, showed significantly reduced NVS at 241 ms during the novel condition. However, to our knowledge, there has been only a single CSD study on anxiety. In a group of individuals with social anxiety, Pause et al. (2010) examined N1 and P3 components of the olfactory potentials in response to chemosensory anxiety signals (i.e., smelling sweat samples donated
