Whereas ERPs provide direct, real-time measures of brain activity associated with successive stages of information processing, they lack the spatial resolution supplied by other neuroimaging methods that indirectly quantify neuronal activity. However, the reference-free ERP/CSD approach addresses this limitation by eliminating many of the pitfalls of volume-conducted scalp potentials (e.g., redundancy, reference-dependence), thereby effectively bridging the gap between surface potentials and their underlying neuroanatomical generators (Kayser and Tenke, 2006a). Future approaches will likely include combined measurements of electrophysiologic and metabolic brain responses in schizophrenia during word recognition memory tasks to further narrow the gap between scalp current flow estimates and underlying brain activation.
