Summary
Sources of the somatosensory evoked fields (SEF) for one subject were estimated using constraints from the magnetic resonance images (MRI) of the same subject. A realistic volume conductor model was shaped corresponding to the inside of the skull. Sources were restricted to a dipole patch riding on the surface of the cortex, reconstructed from the individual MRI. Such a patch can be considered as a uniformly activated cortical area giving rise to distributed currents which flow perpendicular to the cortical surface. Source locations obtained for the SEF in response to separate stimulations of lower lip, first and fifth digit, and collarbone followed the course of the contralateral central sulcus. The order of the estimated source locations was in agreement with the somatosensory homunculus of Penfield and Rasmussen. Similar results were obtained with the simple model of a current dipole in a homogeneous sphere. In contrast, combining a current dipole model with a realistic volume conductor model was rather problematic as it overestimates the radial dipole component by an order of magnitude.
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Dale, A.M., and Sereno, M.I. Improved localization of cortical activity by combining EEG and MEG with MRI cortical surface reconstruction: a linear approach. J. Cognit. Neurosci., 1993, 5: 162–176.
Fuchs, M., Wagner, M., Wischmann, H.A., Ottenberg, K., and Dössel, O. Possibilities of functional brain imaging using a combination of MEG and MRT. In: C. Pantev, T. Elbert, and B. Lütkenhöner (Eds.), Oscillatory event related brain dynamics. Plenum Press, New York, 1994: 435–457.
Hämäläinen, M.S., and Sarvas, J. Realistic conductivity geometry model of the human head for interpretation of neuromagnetic data. IEEE Trans. Biomed. Eng., 1989, 36: 165–171.
Hari, R., Joutsiniemi, S.L., Sarvas, J. Saptial resolution of neuromagnetic records: Theoretical calculations in a spherical model. Electroenceph. clin. Neurophysiol., 1988, 71: 64–72.
Kuriki, S., Isobe, Y., Mizutani, Y., and Murase, M. Magnetic responses evoked by verbal and nonverbal stimuli. In: K. Atsumi, M. Kotani, S. Ueno, T. Katila, and S.J. Williamson (eds.), Biomagnetism '87. Tokyo Denki University Press, Tokyo, 1988: pp. 262–265.
Kuriki, S., Murase, M., Takeuchi, F. Locating accuracy of a current source of neuromagnetic responses: Simulation study for a single current dipole in a spherical conductor. Electroenceph. clin. Neurophysiol., 1989, 73: 499–506.
Lehnertz, K., Lütkenhöner, B., Hoke, M., Pantev, C. Considerations on a spatio-temporal two-dipole model. In: Advances in Biomagnetism (S.J. Williamson, M. Hoke, G. Stroink, M. Kotani, eds.), Plenum Press, New York, 1989: pp. 563–566.
Lütkenhöner, B. A simulation study of the resolving power of the biomagnetic inverse procedure. Clin. Phys. Physiol. Meas., 1991, vol. 12, suppl. A, pp. 73–78.
Lütkenhöner, B. On the biomagnetic inverse procedure's capability of separating two current dipoles with priori known locations, in: Biomagnetism: Clinical Aspects (M. Hoke, S.N. Erné, Y.C. Okada, G.L. Romani, eds.), Excerpta Medica, Amsterdam, 1992a: pp. 687–692.
Lütkenhöner, B. Möglichkeiten und Grenzen der neuromagnetischen Quellenanalyse. Münster/Hamburg: Lit, 1992b.
Lütkenhöner, B. Dipole and multidipole source analysis of magnetic fields: Possibilities and limitations. In: Proceedings of the 9th International Conference on Biomagnetism (L. Deecke, C. Baumgartner, eds.), Elsevier, Amsterdam, 1994a (in press).
Lütkenhöner, B. Effect of parameter space reduction on dipole localization accuracy exemplified for a simple model of a sulcus of the brain. In: Proceedings of the 9th International Conference on Biomagnetism (L. Deecke, C. Baumgartner, eds.), Elsevier, Amsterdam, 1994b (in press).
Lütkenhöner, B., Pantev, C., Hoke, M. Comparison between different methods to approximate an area of the human head by a sphere. In: Auditory evoked magnetic fields and potentials (F. Grandori, M. Hoke, G.L. Romani, eds.), Advances in audiology, vol. 6, Karger, Basel, 1990: pp. 103–118.
Lütkenhöner, B., Lehnertz, K., Hoke, M., Pantev, C. On the biomagnetic inverse problem in the case of multiple dipoles. Acta OtoLaryngol. (Stockh.), 1991, suppl. 491: 94–105.
Lütkenhöner, B., Pantev, C., Hoke, M. Interpretation of auditory evoked magnetic fields in terms of two simul-taneously active dipoles. Biomed. Res., 1992, vol. 13, suppl. 1, pp. 17–22.
Lütkenhöner, B., and Pantev, C. The exogenous components of the auditory evoked field: current status, in: Biomagnetism: Clinical Aspects (M. Hoke, S.N. Erné, Y.C. Okada, G.L. Romani, eds.), Excerpta Medica, Amsterdam, 1992: pp. 143–152.
Meijs, J.W.H., Bosch, C., Peters, M.J., Lopez da Silva, F.H. On the magnetic field distribution generated by a dipolar current source situated in a realistically shaped compartment model of the head. Electroenceph. clin. Neurophysiol., 1987, 66: 286–298.
Menninghaus, E., Lütkenhöner, B., and Gonzalez, S.L. Localization of a dipolar source in a skull phantom: Realistic versus spherical model. IEEE Trans. Biomed. Eng., 1994, 41: 986–989.
Menninghaus, E., and Lütkenhöner, B. How silent are deep and radial sources in neuromagnetic measurements. In: Proceedings of the 9th International Conference on Biomagnetism (L. Deecke, C. Baumgartner, eds.), Elsevier, Amsterdam, 1994 (in press).
Mosher, J.C., Lewis, P.S., and Leahy, R.M. Multiple dipole modeling and localization from spatio-temporal MEG data. IEEE Trans. Biomed. Eng., 1992, 39: 541–557.
Pantev, C., Hoke, M., Lehnertz, K., Lütkenhöner, B., Fahrendorf, G., Stöber, U. Identification of sources of brain neuronal activity with high spatiotemporal resolution through combination of neuromagnetic source localization (NMSL) and magnetic resonance imaging (MRI). Electroenceph. clin. Neurophysiol., 1990, 75: 173–184.
Penfield, W., and Rasmussen, T. The cerebral cortex of man: A clinical study of localization and function. New York: Macmillan, 1950.
Press, W.H., Teukolsky, S.A., Vetterling, W.T., and Flannery, B.P. Numerical recipes in C. The art of scientific computing. Cambridge Unviversity Press, Cambridge, MA, 1992.
Reite, M., Teale, P., Zimmermann, J., David, K., and Whalen, J. Source location of a 50 msec latency auditory evoked field component. Electroenceph. clin. Neurophysiol., 1988, 70: 490–498.
Steinsträter, Olaf. Rekonstruktion der Kortexoberfläche auf der Basis von Magnetresonanztomographiedaten. Diplomarbeit, University of Münster, 1994.
Tan, S., Roth, B.J., Wikswo, J.P. The magnetic field of cortical current sources: the application of a spatial filtering model to the forward and inverse problems. Electroenceph. clin. Neurophysiol., 1990, 76: 73–85.
Wieringa, H.J. MEG, EEG and the integration with magnetic resonance images. PhD thesis, Enschede, 1993.
Yamamoto, T., Williamson, S.J., Kaufman, L., Nicholson, C., and Llinas, R. Neuromagnetic localization of neuronal activity in the human brain. Proc. Natl. Acad. Sci. USA, 1988, 85: 8732–8736.
Young, C., Wells, D. Ray Tracing Creations. 2nd edition, Waite Group Press, Corte Madera, CA, 1994.
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This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Klinische Forschergruppe ‘Biomagnetismus und Biosignalanalyse’).
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Lütkenhöner, B., Menninghaus, E., Steinsträter, O. et al. Neuromagnetic source analysis using magnetic resonance images for the construction of source and volume conductor model. Brain Topogr 7, 291–299 (1995). https://doi.org/10.1007/BF01195255
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DOI: https://doi.org/10.1007/BF01195255