title: A method for localization of sources of human cerebral potentials evoked by sensory stimuli.
abstract: A method based on potential field theory is described for assessing the location and orientation of dipole generators of the human scalp-recorded sensory evoked potential (EP). The method assumes that the EP at a given moment is due to a single dipole source and that the head can be modeled by a homogeneous conductive sphere (brain) surrounded by inner (skull) and outer (scalp) shells of differing conductivity (three-sphere model).  Solution for source location and orientation from the surface potential field is given for the case of a single homogeneous sphere (one-sphere model). It is then shown that a unique solution for the three-sphere model can be derived from the one-sphere solution. Solutions are obtained by application of an iterative procedure which minimizes the error between calculated and empirical potential fields. A test of the method is described in which the calculated location and orientation of a dipole was in good agreement with the known source of an early component of the human somatosensory EP.
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003201:Computers; D005071:Evoked Potentials; D006801:Humans; D008959:Models, Neurological; D011603:Psychophysiology; D012535:Scalp / Q000294:innervation; D012677:Sensation / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology