MEG and ECoG localization accuracy test

Sina Gharib, William W. Sutherling, Nobukazu Nakasato, Daniel S. Barth, Christoph Baumgartner, N. Alexopoulos, Steve Taylor, Robert L. Rogers

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


We tested the localization accuracy of magnetoencephalography (MEG) and electrocorticography (ECoG) for a current dipole in a saline filled sphere at depths ranging from 1 to 6 cm at 1 cm intervals. We used standard neuromagnetometer placements and subdural electrode grids, previously employed for patient studies, with precise measurements of sensor and electrode locations with a 3-dimensional spatial digitizer. MEG and ECoG had comparable accuracy with mean errors of 1.5 and 1.8 mm, respectively. It appears that use of the spatial digitizer increases accuracy for both MEG and EGoG localizations. The larger errors in the ECoG with increasing depths could be attributed to under-sampling of the spatial pattern of the field which spreads out with deeper sources. It should be noted that in clinical applications a grid of the dimensions used here would most typically be used for superficial sources on the cortex with depth recordings being preferred for investigations of deep epileptogenic activity. Results are encouraging for continued development of non-invasive MEG methods for further definition of epileptogenic zones in the brain.

Original languageEnglish
Pages (from-to)109-114
Number of pages6
JournalElectroencephalography and Clinical Neurophysiology
Issue number2
Publication statusPublished - 1995 Feb


  • Electrocorticography (ECoG)
  • Localization accuracy
  • Magnetoeneephalography (MEG)

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology


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