In electrophysiology, the surface Laplacian has found use in applications in which sharp localization is expected, as is the case for ERP generators associated with neuronal activation in well-defined motor or sensory structures. For instance, the auditory N1 provides a well-studied model of historic relevance to the electrophysiologic study of functional localization. MEG and intracranial methods suggest multiple generators in Heschl’s gyrus and the planum temporale (Godey et al, 2001). However, the human AEP N1 component occurs much later than the initial response of primary cortex, its generators are not as sharply localized to Heschl’s gyrus (Liegeois Chauvel et al., 1994), and subdural electrode grids identify a corresponding maximum over posterior portions of the Sylvian fissure and upper superior temporal gyrus (Neelon et al., 2006). Despite these caveats, the auditory N1 component is particularly well-suited to showcase the merits of CSD methods.
