Evoked potentials (EPs) provide an anatomical method that yields time-locked indices of information processing by, and transfer through, neural structures. Early applications of EPs gave insights into functional neuroanatomy by mapping activity through well-defined pathways from the sense organs through the central nervous system (CNS) in anesthetized animals (e.g., Marshall, Woolsey and Bard, 1937; Mountcastle and Henneman, 1952; Rose and Woolsey, 1949). Beyond the sensory and motor systems, this approach allowed the systematic visualization and parsing of neuroanatomical processing, as evidenced by transit times and response morphology following electrical or sensory stimulation. These same anatomical considerations are preserved when the approach is generalized as the event-related potential (ERP), which incorporates a myriad of sensory, motor and cognitive paradigms (cf. Kayser and Tenke, 2005; Luck, 2005; Picton et al., 2000). However, even when the anatomical underpinnings of an ERP provide a characteristic electrical pattern (signature) in its waveform (timing), these properties may be obscured by the overlap in time and space from simultaneous activity within multiple neuronal regions and networks. Moreover, since electrical measurements are potential differences (i.e., voltages), the resulting
