Empirical comparison of the MEG and EEG: animal models of the direct cortical response and epileptiform activity in neocortex. Journal Article uri icon



  • This review directly addresses the appropriateness of the dipole model as a physical representation of neocortical sources produced by evoked and spontaneous epileptiform activity in neocortex. Three dimensional electrical measurements of cellular currents in rat sensory neocortex are compared to the extracranial magnetic fields these currents produce. Comparisons are performed for the direct cortical response (DCR) evoked by electrical stimulation of the cortical surface, and for evoked and spontaneous interictal and ictal discharge of the penicillin focus in the same animal preparation. Our data support the hypothesis that evoked and epileptiform magnetic fields result from intradendritic currents oriented perpendicular to the cortical surface. Furthermore, magnetic fields can be detected from epileptic foci smaller than 3 x 3 mm2. This work provides an empirical foundation for physical models with which to interpret noninvasive neuromagnetic recordings of epileptic discharge in human focal seizure disorders. The dipole approximation appears to be appropriate for the interpretation of magnetic field phenomena in neocortex.

publication date

  • January 1, 1991

has subject area

has restriction

  • closed

Date in CU Experts

  • October 14, 2013 3:16 AM

Full Author List

  • Barth DS

author count

  • 1

citation count

  • 0

Other Profiles

International Standard Serial Number (ISSN)

  • 0896-0267

Electronic International Standard Serial Number (EISSN)

  • 1573-6792

Additional Document Info

start page

  • 85

end page

  • 93


  • 4


  • 2