Localization of auditory response sources using magnetoencephalography and magnetic resonance imaging
A. C. Papanicolaou, S. Baumann, R. L. Rogers, C. Saydjari, E. G. Amparo and H. M. Eisenberg
Division of Neurosurgery, University of Texas Medical Branch, Galveston 77550.
Magnetoencephalography offers the possibility of localizing accurately and
noninvasively the source of intracranial currents associated with normal
and abnormal brain activity. The purpose of this study was to assess the
validity and across-subject reliability of localization of cortical sources
responding to ipsilateral and contralateral auditory stimulation. Magnetic
evoked fields to both stimulation conditions were measured in eight
consecutive normal subjects, and the cortical sources of these fields were
estimated on the basis of these measurements. Subsequent projection of the
source location coordinates onto magnetic resonance images showed that in
all subjects the sources were accurately estimated to fall in the vicinity
of the auditory cortex and that two separate sources may account for the
response to ipsilateral and contralateral stimulation.
