What is Magnetoencephalography and why it is Relevant to Neurosurgery?

  • F. H. da Lopes Silva
Part of the Advances and Technical Standards in Neurosurgery book series (NEUROSURGERY, volume 30)


Magnetoencephalography (MEG) is a relatively novel technique that allows the study of the dynamic properties of cortical activity. The functional localization of brain sources of MEG signals depends on the models used and it always has a certain degree of uncertainty. Nevertheless, MEG can be very useful in assisting the neurosurgeon in planning and carrying out brain surgery in, or around, eloquent brain areas, and in epilepsy surgery in pharmaco-resistant patients. The following three areas of application of MEG in neurosurgery are reviewed: (i) Presurgical functional localization of somatomotor eloquent cortex; (ii) Presurgical evaluation of epileptic patients. (iii) Functional localization of speech relevant brain areas. The performance of MEG in comparison with EEG and fMRI is discussed.


Magnetoencephalography epilepsy presurgical planning 


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  1. 1.
    Allison T, McCarthy G et al (1989) Human cortical potentials evoked by stimulation of the median nerve. J Neurophysiol 62: 694–710PubMedGoogle Scholar
  2. 2.
    Allison T, McCarthy G et al (1991) Potentials evoked in human and monkey cerebral cortex by stimulation of the median nerve: a review of scalp and intracranial recordings. Brain 114: 2465–2503PubMedGoogle Scholar
  3. 3.
    Anastasiadis PG, Kotini A, Anninos P, Adamopoulos A, Sigalas J, Koutlaki N (2003) Chaotic and periodic analysis of fetal magnetocardiogram recordings in growth restriction. Prenat Diagn 23(5): 405–409PubMedGoogle Scholar
  4. 4.
    Baumgartner C, Pataraia E et al (2000) Magnetoencephalography in focal epilepsy. Epilepsia 41[Suppl] 3: S39–S47PubMedGoogle Scholar
  5. 5.
    Buchner H, Fuchs M et al (1994) Source analysis of median nerve and finger stimulated somatosensory evoked potentials: multichannel simultaneous recording of electric and magnetic fields combined with 3D MRI tomography. Brain Topography 6: 299–310PubMedGoogle Scholar
  6. 6.
    Cohen D (1968) Magnetoencephalography: evidence of magnetic field produced by alpha-rhythm currents. Science 161: 784–786PubMedGoogle Scholar
  7. 7.
    Disbrow EA, Slutsky DA et al (2000) Functional MRI at 1.5 tesla: a comparison of the blood oxygenation level-dependent signal and electrophysiology. Proc Natl Acad Sci USA 97(17): 9718–9723PubMedGoogle Scholar
  8. 8.
    Ebersole JS (1997) Defining epileptogenic foci: past, present and future. J Clin Neurophysiol 14: 470–483PubMedGoogle Scholar
  9. 9.
    Engel J Jr (1993) Intracerebral recordings: organization of the human epileptogenic region. J Clin Neurophysiol 10: 90–98PubMedGoogle Scholar
  10. 10.
    Ganslandt O, Fahlbusch R et al (1999) Functional neuronavigation with magnetoencephalography: outcome in 50 patients with lesions around the motor cortex. J Neurosurg 91(1): 73–79PubMedGoogle Scholar
  11. 11.
    Gootjes L, Raij T et al (1999) Left-hemisphere dominance for processing of vowels: a whole-scalp neuromagnetic study. Neuroreport 10(14): 2987–2991PubMedGoogle Scholar
  12. 12.
    Gotman J, Wang IY (1991) State-dependent spike detection: concepts and preliminary results. Electroenceph Clin Neurophysiol 79: 11–19PubMedGoogle Scholar
  13. 13.
    Hari R, Forss N (1999) Magnetoencephalography in the study of human somatosensory cortical processing. Phil Trans R Soc Lond B 354: 1145–1154Google Scholar
  14. 14.
    Hari R, Reinikerinen K et al (1984) Somatosensory evoked cerebral magnetic fields from SI and SII in man. Electroenceph Clin Neurophysiol 57: 254–263PubMedGoogle Scholar
  15. 15.
    Hari R, Salenius S (1999) Rhythmical corticomotor communication. Neuro-Report 10: R1–R10Google Scholar
  16. 16.
    Inoue T, Shimizu H et al (1999) Accuracy and limitation of functional magnetic resonance for identification of central sulcus: comparison with magnetoencephalography in patients with brain tumours. Neuroimage 10: 738–748PubMedGoogle Scholar
  17. 17.
    Iwasaki M, Nakasato N et al (2002) Surgical implications of neuromagnetic spike localization in temporal lobe epilepsy. Epilepsia 43: 415–424PubMedGoogle Scholar
  18. 18.
    Kanzaki H, Nakatani S, Kandori A, Tsukada K, Miyatake K (2003) A new screening method to diagnose coronary artery disease using multichannel magnetocardiogram and simple exercise. Basic Res Cardiol 98(2): 124–132PubMedGoogle Scholar
  19. 19.
    Kober H, Moller M et al (2001) New approach to localize speech relevant brain areas and hemispheric dominance using spatially filtered magnetoencephalography. Hum Brain Mapp 14(4): 236–250PubMedGoogle Scholar
  20. 20.
    Kober H, Nimsky C et al (2001) Correlation of sensorimotor activation with functional magnetic resonance imaging and magnetoencephalography in presurgical functional imaging: a spatial analysis. Neuroimage 14(5): 1214–1228PubMedGoogle Scholar
  21. 21.
    Lantz G, Wahlberg P et al (1998) Categorization of inter-ictal epileptiform potentials using a graphic-theoretic method. Electroenceph Clin Neurophysiol 107: 323–331PubMedGoogle Scholar
  22. 22.
    Mäkelä JP, Kirveskari E et al (2001) Three-dimensional integration of brain anatomy and function to facilitate intraoperative navigation around the sensorimotor strip. Human Brain Mapping 12: 180–192PubMedGoogle Scholar
  23. 23.
    Malonek D, Dirnagl U et al (1997) Vascular imprints of neuronal activity: relationships between the dynamics of cortical blood flow, oxygenation, and volume changes following sensory stimulation. Proc Natl Acad Sci USA 94(26): 14826–14831PubMedGoogle Scholar
  24. 24.
    Mauguiere F (1998) Somatosensory evoked potentials: normal reposnses, abnormal waveforms and clinical applications in neurological diseases. 1014–1058Google Scholar
  25. 25.
    Momjian S, Seghier M et al (2003) Mapping of the neuronal networks of human cortical brain functions. Adv Tech Stand Neurosurg 28: 91–142PubMedGoogle Scholar
  26. 26.
    Okada YC, Tanenbaum R et al (1984) Somatotopic organization of the human somatosensory cortex revealed by neuromagnetic measurements. Exp Brain Res 56(197–205)PubMedGoogle Scholar
  27. 27.
    Ossenblok P, Fuchs M et al (1999) Source analysis of lesional frontal lobe epilepsy. IEEE Eng Med Biol Mag 18: 67–77Google Scholar
  28. 28.
    Ossenblok P, Luiten FSS et al (2003) Magnetic source imaging contributes to the presurgical identification of sensorimotor cortex in patients with frontal lobe epilepsy. Clin Neurophysiol 114: 212–232Google Scholar
  29. 29.
    Papanicolaou AC, Simos PG et al (1999) Magnetoencephalographic mapping of the language specific cortex. J Neurosurgery 90: 85–93Google Scholar
  30. 30.
    Rezai AR, Hund M et al (1996) The interactive use of magneto-encephalography in stereotaxic image-guided neurosurgery. Neurosurgery 39(1): 92–102PubMedGoogle Scholar
  31. 31.
    Robinson SE, Rose DG (1992) Current source image estimation by spatial filtered MEGGoogle Scholar
  32. 32.
    Salenius S, Portin K et al (1997) Cortical control of human motorneuron firing during isometyric contractions. J Neurophysiol 77: 3401–3405PubMedGoogle Scholar
  33. 33.
    Salmelin R, Hari R et al (1994) Dynamics of brain activation during picture naming. Nature 368: 463–465PubMedGoogle Scholar
  34. 34.
    Stefan H, Hummel C et al (2000) Magnetoencephalography in extratemporal epilepsy. J Clin Neurophysiol 17: 190–200PubMedGoogle Scholar
  35. 35.
    Sutherling WW, Crabdall P et al (1988) The magnetic and electric fields agree with intracranial localization of somtaosensory cortex. Neurology 38: 373–381Google Scholar
  36. 36.
    Sutherling WW, Levesque MF et al (1991) Localization of partial epilepsy using magnetic and electric measurements. Epilepsia 32[Suppl] 5: S29–S40PubMedGoogle Scholar
  37. 37.
    Van’t Ent D, Manshanden I et al (2003) Spike Cluster analysis in neocortical localization related epilepsy achieves clinically significant source localization results in MEG. Clin Neurophysiol (in press)Google Scholar
  38. 38.
    Van’t Ent D, Manshanden I et al (2003) Spike cluster analysis in neocortical localization related epilepsy yields clinically significant equivalent source localization results in magnetoencephalogram (MEG). Clin NeurophysiolGoogle Scholar
  39. 39.
    Wada J, Rasmussen T (1960) Intracarotid injection of sodium amytal for the lateralization of cerebral speech dominance. J Neurosurgery 17: 266–282Google Scholar
  40. 40.
    Wahlberg P, Lantz G (2000) Methods for robust clustering of epileptic EEG spikes. IEEE Trans Biomed Eng 47: 857–868PubMedGoogle Scholar
  41. 41.
    Wilson SB, Turner CA et al (1999) Spike detection. II. Automatic, perception-based detection and clustering. Clin Neurophysiol 110: 404–411PubMedGoogle Scholar
  42. 42.
    Wood CC, Cohen D et al (1985) Electrical sources in human somatosensory cortex: identification by combined magnetic and potential recordings. Science 227: 1051–1053PubMedGoogle Scholar
  43. 43.
    Zilles K, Schlaug G et al (1995) Mapping of human and macaque sensorimotor areas by integrating architectonic, transmitter receptor, MRI and PET data. J Anat 187(Pt 3): 515–537PubMedGoogle Scholar

Copyright information

© Springer-Verlag/Wien 2005

Authors and Affiliations

  • F. H. da Lopes Silva
    • 1
  1. 1.Section Neurobiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamAmsterdamThe Netherlands

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