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Philosophical Transactions of the Royal Society B: Biological Sciences logoLink to Philosophical Transactions of the Royal Society B: Biological Sciences
. 1999 Jul 29;354(1387):1145–1154. doi: 10.1098/rstb.1999.0470

Magnetoencephalography in the study of human somatosensory cortical processing.

R Hari 1, N Forss 1
PMCID: PMC1692629  PMID: 10466142

Abstract

Magnetoencephalography (MEG) is a totally non-invasive research method which provides information about cortical dynamics on a millisecond time-scale. Whole-scalp magnetic field patterns following stimulation of different peripheral nerves indicate activation of an extensive cortical network. At the SI cortex, the responses reflect mainly the activity of area 3b, with clearly somatotopical representations of different body parts. The SII cortex is activated bilaterally and it also receives, besides tactile input, nociceptive afference. Somatically evoked MEG signals may also be detected from the posterior parietal cortex, central mesial cortex and the frontal lobe. The serial versus parallel processing in the cortical somatosensory network is still under debate.

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Selected References

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  1. Allison T., McCarthy G., Wood C. C., Jones S. J. Potentials evoked in human and monkey cerebral cortex by stimulation of the median nerve. A review of scalp and intracranial recordings. Brain. 1991 Dec;114(Pt 6):2465–2503. doi: 10.1093/brain/114.6.2465. [DOI] [PubMed] [Google Scholar]
  2. Allison T., McCarthy G., Wood C. C., Williamson P. D., Spencer D. D. Human cortical potentials evoked by stimulation of the median nerve. II. Cytoarchitectonic areas generating long-latency activity. J Neurophysiol. 1989 Sep;62(3):711–722. doi: 10.1152/jn.1989.62.3.711. [DOI] [PubMed] [Google Scholar]
  3. Baumgartner C., Doppelbauer A., Deecke L., Barth D. S., Zeitlhofer J., Lindinger G., Sutherling W. W. Neuromagnetic investigation of somatotopy of human hand somatosensory cortex. Exp Brain Res. 1991;87(3):641–648. doi: 10.1007/BF00227089. [DOI] [PubMed] [Google Scholar]
  4. Biermann K., Schmitz F., Witte O. W., Konczak J., Freund H. J., Schnitzler A. Interaction of finger representation in the human first somatosensory cortex: a neuromagnetic study. Neurosci Lett. 1998 Jul 17;251(1):13–16. doi: 10.1016/s0304-3940(98)00480-7. [DOI] [PubMed] [Google Scholar]
  5. Brenner D., Lipton J., Kaufman L., Williamson S. J. Somatically evoked magnetic fields of the human brain. Science. 1978 Jan 6;199(4324):81–83. doi: 10.1126/science.199.4324.81. [DOI] [PubMed] [Google Scholar]
  6. Burton H., Videen T. O., Raichle M. E. Tactile-vibration-activated foci in insular and parietal-opercular cortex studied with positron emission tomography: mapping the second somatosensory area in humans. Somatosens Mot Res. 1993;10(3):297–308. doi: 10.3109/08990229309028839. [DOI] [PubMed] [Google Scholar]
  7. Caselli R. J. Ventrolateral and dorsomedial somatosensory association cortex damage produces distinct somesthetic syndromes in humans. Neurology. 1993 Apr;43(4):762–771. doi: 10.1212/wnl.43.4.762. [DOI] [PubMed] [Google Scholar]
  8. Curio G., Mackert B. M., Burghoff M., Koetitz R., Abraham-Fuchs K., Härer W. Localization of evoked neuromagnetic 600 Hz activity in the cerebral somatosensory system. Electroencephalogr Clin Neurophysiol. 1994 Dec;91(6):483–487. doi: 10.1016/0013-4694(94)90169-4. [DOI] [PubMed] [Google Scholar]
  9. Curio G., Mackert B. M., Burghoff M., Neumann J., Nolte G., Scherg M., Marx P. Somatotopic source arrangement of 600 Hz oscillatory magnetic fields at the human primary somatosensory hand cortex. Neurosci Lett. 1997 Oct 3;234(2-3):131–134. doi: 10.1016/s0304-3940(97)00690-3. [DOI] [PubMed] [Google Scholar]
  10. Deisz R. A., Prince D. A. Frequency-dependent depression of inhibition in guinea-pig neocortex in vitro by GABAB receptor feed-back on GABA release. J Physiol. 1989 May;412:513–541. doi: 10.1113/jphysiol.1989.sp017629. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Elbert T., Flor H., Birbaumer N., Knecht S., Hampson S., Larbig W., Taub E. Extensive reorganization of the somatosensory cortex in adult humans after nervous system injury. Neuroreport. 1994 Dec 20;5(18):2593–2597. doi: 10.1097/00001756-199412000-00047. [DOI] [PubMed] [Google Scholar]
  12. Elbert T., Pantev C., Wienbruch C., Rockstroh B., Taub E. Increased cortical representation of the fingers of the left hand in string players. Science. 1995 Oct 13;270(5234):305–307. doi: 10.1126/science.270.5234.305. [DOI] [PubMed] [Google Scholar]
  13. Elbert T., Sterr A., Flor H., Rockstroh B., Knecht S., Pantev C., Wienbruch C., Taub E. Input-increase and input-decrease types of cortical reorganization after upper extremity amputation in humans. Exp Brain Res. 1997 Oct;117(1):161–164. doi: 10.1007/s002210050210. [DOI] [PubMed] [Google Scholar]
  14. Flor H., Elbert T., Knecht S., Wienbruch C., Pantev C., Birbaumer N., Larbig W., Taub E. Phantom-limb pain as a perceptual correlate of cortical reorganization following arm amputation. Nature. 1995 Jun 8;375(6531):482–484. doi: 10.1038/375482a0. [DOI] [PubMed] [Google Scholar]
  15. Forss N., Hari R., Salmelin R., Ahonen A., Hämäläinen M., Kajola M., Knuutila J., Simola J. Activation of the human posterior parietal cortex by median nerve stimulation. Exp Brain Res. 1994;99(2):309–315. doi: 10.1007/BF00239597. [DOI] [PubMed] [Google Scholar]
  16. Forss N., Jousmäki V. Sensorimotor integration in human primary and secondary somatosensory cortices. Brain Res. 1998 Jan 19;781(1-2):259–267. doi: 10.1016/s0006-8993(97)01240-7. [DOI] [PubMed] [Google Scholar]
  17. Forss N., Merlet I., Vanni S., Hämäläinen M., Mauguière F., Hari R. Activation of human mesial cortex during somatosensory target detection task. Brain Res. 1996 Sep 23;734(1-2):229–235. [PubMed] [Google Scholar]
  18. Forss N., Salmelin R., Hari R. Comparison of somatosensory evoked fields to airpuff and electric stimuli. Electroencephalogr Clin Neurophysiol. 1994 Nov;92(6):510–517. doi: 10.1016/0168-5597(94)90135-x. [DOI] [PubMed] [Google Scholar]
  19. Garcha H. S., Ettlinger G. The effects of unilateral or bilateral removals of the second somatosensory cortex (area SII): a profound tactile disorder in monkeys. Cortex. 1978 Sep;14(3):319–326. doi: 10.1016/s0010-9452(78)80060-4. [DOI] [PubMed] [Google Scholar]
  20. Hari R., Aittoniemi K., Järvinen M. L., Katila T., Varpula T. Auditory evoked transient and sustained magnetic fields of the human brain. Localization of neural generators. Exp Brain Res. 1980;40(2):237–240. doi: 10.1007/BF00237543. [DOI] [PubMed] [Google Scholar]
  21. Hari R., Hämäläinen H., Hämäläinen M., Kekoni J., Sams M., Tiihonen J. Separate finger representations at the human second somatosensory cortex. Neuroscience. 1990;37(1):245–249. doi: 10.1016/0306-4522(90)90210-u. [DOI] [PubMed] [Google Scholar]
  22. Hari R., Hämäläinen M., Kaukoranta E., Reinikainen K., Teszner D. Neuromagnetic responses from the second somatosensory cortex in man. Acta Neurol Scand. 1983 Oct;68(4):207–212. doi: 10.1111/j.1600-0404.1983.tb04828.x. [DOI] [PubMed] [Google Scholar]
  23. Hari R., Hänninen R., Mäkinen T., Jousmäki V., Forss N., Seppä M., Salonen O. Three hands: fragmentation of human bodily awareness. Neurosci Lett. 1998 Jan 16;240(3):131–134. doi: 10.1016/s0304-3940(97)00945-2. [DOI] [PubMed] [Google Scholar]
  24. Hari R., Karhu J., Hämäläinen M., Knuutila J., Salonen O., Sams M., Vilkman V. Functional organization of the human first and second somatosensory cortices: a neuromagnetic study. Eur J Neurosci. 1993 Jun 1;5(6):724–734. doi: 10.1111/j.1460-9568.1993.tb00536.x. [DOI] [PubMed] [Google Scholar]
  25. Hari R., Kaukoranta E., Reinikainen K., Huopaniemie T., Mauno J. Neuromagnetic localization of cortical activity evoked by painful dental stimulation in man. Neurosci Lett. 1983 Nov 21;42(1):77–82. doi: 10.1016/0304-3940(83)90425-1. [DOI] [PubMed] [Google Scholar]
  26. Hari R., Nagamine T., Nishitani N., Mikuni N., Sato T., Tarkiainen A., Shibasaki H. Time-varying activation of different cytoarchitectonic areas of the human SI cortex after tibial nerve stimulation. Neuroimage. 1996 Oct;4(2):111–118. doi: 10.1006/nimg.1996.0035. [DOI] [PubMed] [Google Scholar]
  27. Hari R. On brain's magnetic responses to sensory stimuli. J Clin Neurophysiol. 1991 Apr;8(2):157–169. doi: 10.1097/00004691-199104000-00004. [DOI] [PubMed] [Google Scholar]
  28. Hari R., Portin K., Kettenmann B., Jousmäki V., Kobal G. Right-hemisphere preponderance of responses to painful CO2 stimulation of the human nasal mucosa. Pain. 1997 Aug;72(1-2):145–151. doi: 10.1016/s0304-3959(97)00023-7. [DOI] [PubMed] [Google Scholar]
  29. Hari R., Reinikainen K., Kaukoranta E., Hämäläinen M., Ilmoniemi R., Penttinen A., Salminen J., Teszner D. Somatosensory evoked cerebral magnetic fields from SI and SII in man. Electroencephalogr Clin Neurophysiol. 1984 Mar;57(3):254–263. doi: 10.1016/0013-4694(84)90126-3. [DOI] [PubMed] [Google Scholar]
  30. Hari R., Salenius S. Rhythmical corticomotor communication. Neuroreport. 1999 Feb 5;10(2):R1–10. [PubMed] [Google Scholar]
  31. Hari R., Salmelin R. Human cortical oscillations: a neuromagnetic view through the skull. Trends Neurosci. 1997 Jan;20(1):44–49. doi: 10.1016/S0166-2236(96)10065-5. [DOI] [PubMed] [Google Scholar]
  32. Hashimoto I., Mashiko T., Imada T. Somatic evoked high-frequency magnetic oscillations reflect activity of inhibitory interneurons in the human somatosensory cortex. Electroencephalogr Clin Neurophysiol. 1996 May;100(3):189–203. doi: 10.1016/0168-5597(95)00244-8. [DOI] [PubMed] [Google Scholar]
  33. Hoshiyama M., Kakigi R., Koyama S., Kitamura Y., Shimojo M., Watanabe S. Somatosensory evoked magnetic fields following stimulation of the lip in humans. Electroencephalogr Clin Neurophysiol. 1996 Mar;100(2):96–104. doi: 10.1016/0013-4694(95)00241-3. [DOI] [PubMed] [Google Scholar]
  34. Huttunen J., Ahlfors S., Hari R. Interaction of afferent impulses in the human primary sensorimotor cortex. Electroencephalogr Clin Neurophysiol. 1992 Mar;82(3):176–181. doi: 10.1016/0013-4694(92)90165-e. [DOI] [PubMed] [Google Scholar]
  35. Huttunen J. Does the P35m SEF deflection really come from the motor cortex? Electroencephalogr Clin Neurophysiol. 1997 Jan;104(1):101–102. doi: 10.1016/s0168-5597(96)96642-3. [DOI] [PubMed] [Google Scholar]
  36. Huttunen J., Hari R., Leinonen L. Cerebral magnetic responses to stimulation of ulnar and median nerves. Electroencephalogr Clin Neurophysiol. 1987 Apr;66(4):391–400. doi: 10.1016/0013-4694(87)90208-2. [DOI] [PubMed] [Google Scholar]
  37. Huttunen J., Kaukoranta E., Hari R. Cerebral magnetic responses to stimulation of tibial and sural nerves. J Neurol Sci. 1987 Jun;79(1-2):43–54. doi: 10.1016/0022-510x(87)90258-9. [DOI] [PubMed] [Google Scholar]
  38. Huttunen J., Kobal G., Kaukoranta E., Hari R. Cortical responses to painful CO2 stimulation of nasal mucosa; a magnetoencephalographic study in man. Electroencephalogr Clin Neurophysiol. 1986 Oct;64(4):347–349. doi: 10.1016/0013-4694(86)90159-8. [DOI] [PubMed] [Google Scholar]
  39. Huttunen J., Wikström H., Korvenoja A., Seppäläinen A. M., Aronen H., Ilmoniemi R. J. Significance of the second somatosensory cortex in sensorimotor integration: enhancement of sensory responses during finger movements. Neuroreport. 1996 Apr 10;7(5):1009–1012. doi: 10.1097/00001756-199604100-00011. [DOI] [PubMed] [Google Scholar]
  40. Iwamura Y. Hierarchical somatosensory processing. Curr Opin Neurobiol. 1998 Aug;8(4):522–528. doi: 10.1016/s0959-4388(98)80041-x. [DOI] [PubMed] [Google Scholar]
  41. Kaas J. H., Nelson R. J., Sur M., Lin C. S., Merzenich M. M. Multiple representations of the body within the primary somatosensory cortex of primates. Science. 1979 May 4;204(4392):521–523. doi: 10.1126/science.107591. [DOI] [PubMed] [Google Scholar]
  42. Kakigi R., Koyama S., Hoshiyama M., Kitamura Y., Shimojo M., Watanabe S. Pain-related magnetic fields following painful CO2 laser stimulation in man. Neurosci Lett. 1995 Jun 2;192(1):45–48. doi: 10.1016/0304-3940(95)11604-u. [DOI] [PubMed] [Google Scholar]
  43. Kakigi R., Koyama S., Hoshiyama M., Shimojo M., Kitamura Y., Watanabe S. Topography of somatosensory evoked magnetic fields following posterior tibial nerve stimulation. Electroencephalogr Clin Neurophysiol. 1995 Aug;95(2):127–134. doi: 10.1016/0013-4694(95)00053-2. [DOI] [PubMed] [Google Scholar]
  44. Karhu J., Hari R., Lu S. T., Paetau R., Rif J. Cerebral magnetic fields to lingual stimulation. Electroencephalogr Clin Neurophysiol. 1991 Nov-Dec;80(6):459–468. doi: 10.1016/0168-5597(91)90127-j. [DOI] [PubMed] [Google Scholar]
  45. Karhu J., Hari R., Mäkelä J. P., Huttunen J., Knuutila J. Cortical somatosensory magnetic responses in multiple sclerosis. Electroencephalogr Clin Neurophysiol. 1992 Sep;83(3):192–200. doi: 10.1016/0013-4694(92)90144-7. [DOI] [PubMed] [Google Scholar]
  46. Karhu J., Hari R., Paetau R., Kajola M., Mervaala E. Cortical reactivity in progressive myoclonus epilepsy. Electroencephalogr Clin Neurophysiol. 1994 Feb;90(2):93–102. doi: 10.1016/0013-4694(94)90001-9. [DOI] [PubMed] [Google Scholar]
  47. Kaukoranta E., Hämäläinen M., Sarvas J., Hari R. Mixed and sensory nerve stimulations activate different cytoarchitectonic areas in the human primary somatosensory cortex SI. Neuromagnetic recordings and statistical considerations. Exp Brain Res. 1986;63(1):60–66. doi: 10.1007/BF00235646. [DOI] [PubMed] [Google Scholar]
  48. Kawamura T., Nakasato N., Seki K., Kanno A., Fujita S., Fujiwara S., Yoshimoto T. Neuromagnetic evidence of pre- and post-central cortical sources of somatosensory evoked responses. Electroencephalogr Clin Neurophysiol. 1996 Jan;100(1):44–50. doi: 10.1016/0168-5597(95)00217-0. [DOI] [PubMed] [Google Scholar]
  49. Kohonen T., Hari R. Where the abstract feature maps of the brain might come from. Trends Neurosci. 1999 Mar;22(3):135–139. doi: 10.1016/s0166-2236(98)01342-3. [DOI] [PubMed] [Google Scholar]
  50. Korvenoja A., Wikstrom H., Huttunen J., Virtanan J., Laine P., Aronen H. J., Seppalainen A. M., Ilmoniemi R. J. Activation of ipsilateral primary sensorimotor cortex by median nerve stimulation. Neuroreport. 1995 Dec 15;6(18):2589–2593. doi: 10.1097/00001756-199512150-00033. [DOI] [PubMed] [Google Scholar]
  51. Lenz F. A., Rios M., Chau D., Krauss G. L., Zirh T. A., Lesser R. P. Painful stimuli evoke potentials recorded from the parasylvian cortex in humans. J Neurophysiol. 1998 Oct;80(4):2077–2088. doi: 10.1152/jn.1998.80.4.2077. [DOI] [PubMed] [Google Scholar]
  52. Levänen S., Jousmäki V., Hari R. Vibration-induced auditory-cortex activation in a congenitally deaf adult. Curr Biol. 1998 Jul 16;8(15):869–872. doi: 10.1016/s0960-9822(07)00348-x. [DOI] [PubMed] [Google Scholar]
  53. Lounasmaa O. V., Hämäläinen M., Hari R., Salmelin R. Information processing in the human brain: magnetoencephalographic approach. Proc Natl Acad Sci U S A. 1996 Aug 20;93(17):8809–8815. doi: 10.1073/pnas.93.17.8809. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Mauguière F., Merlet I., Forss N., Vanni S., Jousmäki V., Adeleine P., Hari R. Activation of a distributed somatosensory cortical network in the human brain. A dipole modelling study of magnetic fields evoked by median nerve stimulation. Part I: Location and activation timing of SEF sources. Electroencephalogr Clin Neurophysiol. 1997 Jul;104(4):281–289. doi: 10.1016/s0013-4694(97)00006-0. [DOI] [PubMed] [Google Scholar]
  55. Mauguière F., Merlet I., Forss N., Vanni S., Jousmäki V., Adeleine P., Hari R. Activation of a distributed somatosensory cortical network in the human brain: a dipole modelling study of magnetic fields evoked by median nerve stimulation. Part II: Effects of stimulus rate, attention and stimulus detection. Electroencephalogr Clin Neurophysiol. 1997 Jul;104(4):290–295. doi: 10.1016/s0013-4694(97)00018-7. [DOI] [PubMed] [Google Scholar]
  56. McCarthy G., Allison T., Spencer D. D. Localization of the face area of human sensorimotor cortex by intracranial recording of somatosensory evoked potentials. J Neurosurg. 1993 Dec;79(6):874–884. doi: 10.3171/jns.1993.79.6.0874. [DOI] [PubMed] [Google Scholar]
  57. Mima T., Nagamine T., Ikeda A., Yazawa S., Kimura J., Shibasaki H. Pathogenesis of cortical myoclonus studied by magnetoencephalography. Ann Neurol. 1998 May;43(5):598–607. doi: 10.1002/ana.410430507. [DOI] [PubMed] [Google Scholar]
  58. Mima T., Nagamine T., Nakamura K., Shibasaki H. Attention modulates both primary and second somatosensory cortical activities in humans: a magnetoencephalographic study. J Neurophysiol. 1998 Oct;80(4):2215–2221. doi: 10.1152/jn.1998.80.4.2215. [DOI] [PubMed] [Google Scholar]
  59. Mitzdorf U. Current source-density method and application in cat cerebral cortex: investigation of evoked potentials and EEG phenomena. Physiol Rev. 1985 Jan;65(1):37–100. doi: 10.1152/physrev.1985.65.1.37. [DOI] [PubMed] [Google Scholar]
  60. Mogilner A., Grossman J. A., Ribary U., Joliot M., Volkmann J., Rapaport D., Beasley R. W., Llinás R. R. Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography. Proc Natl Acad Sci U S A. 1993 Apr 15;90(8):3593–3597. doi: 10.1073/pnas.90.8.3593. [DOI] [PMC free article] [PubMed] [Google Scholar]
  61. Murray E. A., Mishkin M. Relative contributions of SII and area 5 to tactile discrimination in monkeys. Behav Brain Res. 1984 Jan;11(1):67–83. doi: 10.1016/0166-4328(84)90009-3. [DOI] [PubMed] [Google Scholar]
  62. Nagamine T., Mäkelä J., Mima T., Mikuni N., Nishitani N., Satoh T., Ikeda A., Shibasaki H. Serial processing of the somesthetic information revealed by different effects of stimulus rate on the somatosensory-evoked potentials and magnetic fields. Brain Res. 1998 Apr 27;791(1-2):200–208. doi: 10.1016/s0006-8993(98)00095-x. [DOI] [PubMed] [Google Scholar]
  63. Nakamura A., Yamada T., Goto A., Kato T., Ito K., Abe Y., Kachi T., Kakigi R. Somatosensory homunculus as drawn by MEG. Neuroimage. 1998 May;7(4 Pt 1):377–386. doi: 10.1006/nimg.1998.0332. [DOI] [PubMed] [Google Scholar]
  64. Narici L., Modena I., Opsomer R. J., Pizzella V., Romani G. L., Torrioli G., Traversa R., Rossini P. M. Neuromagnetic somatosensory homunculus: a non-invasive approach in humans. Neurosci Lett. 1991 Jan 2;121(1-2):51–54. doi: 10.1016/0304-3940(91)90647-c. [DOI] [PubMed] [Google Scholar]
  65. Okada Y. C., Tanenbaum R., Williamson S. J., Kaufman L. Somatotopic organization of the human somatosensory cortex revealed by neuromagnetic measurements. Exp Brain Res. 1984;56(2):197–205. doi: 10.1007/BF00236274. [DOI] [PubMed] [Google Scholar]
  66. Okada Y. C., Wu J., Kyuhou S. Genesis of MEG signals in a mammalian CNS structure. Electroencephalogr Clin Neurophysiol. 1997 Oct;103(4):474–485. doi: 10.1016/s0013-4694(97)00043-6. [DOI] [PubMed] [Google Scholar]
  67. Pardo J. V., Wood T. D., Costello P. A., Pardo P. J., Lee J. T. PET study of the localization and laterality of lingual somatosensory processing in humans. Neurosci Lett. 1997 Sep 26;234(1):23–26. doi: 10.1016/s0304-3940(97)00650-2. [DOI] [PubMed] [Google Scholar]
  68. Rowe M. J., Turman A. B., Murray G. M., Zhang H. Q. Parallel organization of somatosensory cortical areas I and II for tactile processing. Clin Exp Pharmacol Physiol. 1996 Oct-Nov;23(10-11):931–938. doi: 10.1111/j.1440-1681.1996.tb01145.x. [DOI] [PubMed] [Google Scholar]
  69. Schnitzler A., Salmelin R., Salenius S., Jousmäki V., Hari R. Tactile information from the human hand reaches the ipsilateral primary somatosensory cortex. Neurosci Lett. 1995 Nov 10;200(1):25–28. doi: 10.1016/0304-3940(95)12065-c. [DOI] [PubMed] [Google Scholar]
  70. Schnitzler A., Volkmann J., Enck P., Frieling T., Witte O. W., Freund H. J. Different cortical organization of visceral and somatic sensation in humans. Eur J Neurosci. 1999 Jan;11(1):305–315. doi: 10.1046/j.1460-9568.1999.00429.x. [DOI] [PubMed] [Google Scholar]
  71. Shimojo M., Kakigi R., Hoshiyama M., Koyama S., Kitamura Y., Watanabe S. Intracerebral interactions caused by bilateral median nerve stimulation in man: a magnetoencephalographic study. Neurosci Res. 1996 Jan;24(2):175–181. doi: 10.1016/0168-0102(95)00994-9. [DOI] [PubMed] [Google Scholar]
  72. Sterr A., Müller M. M., Elbert T., Rockstroh B., Pantev C., Taub E. Changed perceptions in Braille readers. Nature. 1998 Jan 8;391(6663):134–135. doi: 10.1038/34322. [DOI] [PubMed] [Google Scholar]
  73. Suk J., Ribary U., Cappell J., Yamamoto T., Llinás R. Anatomical localization revealed by MEG recordings of the human somatosensory system. Electroencephalogr Clin Neurophysiol. 1991 Mar;78(3):185–196. doi: 10.1016/0013-4694(91)90032-y. [DOI] [PubMed] [Google Scholar]
  74. Sutherling W. W., Crandall P. H., Darcey T. M., Becker D. P., Levesque M. F., Barth D. S. The magnetic and electric fields agree with intracranial localizations of somatosensory cortex. Neurology. 1988 Nov;38(11):1705–1714. doi: 10.1212/wnl.38.11.1705. [DOI] [PubMed] [Google Scholar]
  75. Tecchio F., Rossini P. M., Pizzella V., Cassetta E., Romani G. L. Spatial properties and interhemispheric differences of the sensory hand cortical representation: a neuromagnetic study. Brain Res. 1997 Aug 29;767(1):100–108. doi: 10.1016/s0006-8993(97)00741-5. [DOI] [PubMed] [Google Scholar]
  76. Tiihonen J., Hari R., Hämäläinen M. Early deflections of cerebral magnetic responses to median nerve stimulation. Electroencephalogr Clin Neurophysiol. 1989 Jul-Aug;74(4):290–296. doi: 10.1016/0168-5597(89)90059-2. [DOI] [PubMed] [Google Scholar]
  77. Towe A. L. On the nature of the primary evoked response. Exp Neurol. 1966 May;15(1):113–139. doi: 10.1016/0014-4886(66)90038-0. [DOI] [PubMed] [Google Scholar]
  78. Vanni S., Rockstroh B., Hari R. Cortical sources of human short-latency somatosensory evoked fields to median and ulnar nerve stimuli. Brain Res. 1996 Oct 21;737(1-2):25–33. doi: 10.1016/0006-8993(96)00646-4. [DOI] [PubMed] [Google Scholar]
  79. Wang X., Merzenich M. M., Sameshima K., Jenkins W. M. Remodelling of hand representation in adult cortex determined by timing of tactile stimulation. Nature. 1995 Nov 2;378(6552):71–75. doi: 10.1038/378071a0. [DOI] [PubMed] [Google Scholar]
  80. Wikström H., Huttunen J., Korvenoja A., Virtanen J., Salonen O., Aronen H., Ilmoniemi R. J. Effects of interstimulus interval on somatosensory evoked magnetic fields (SEFs): a hypothesis concerning SEF generation at the primary sensorimotor cortex. Electroencephalogr Clin Neurophysiol. 1996 Nov;100(6):479–487. doi: 10.1016/s0921-884x(96)95688-x. [DOI] [PubMed] [Google Scholar]
  81. Wood C. C., Cohen D., Cuffin B. N., Yarita M., Allison T. Electrical sources in human somatosensory cortex: identification by combined magnetic and potential recordings. Science. 1985 Mar 1;227(4690):1051–1053. doi: 10.1126/science.3975600. [DOI] [PubMed] [Google Scholar]
  82. Woolsey C. N., Erickson T. C., Gilson W. E. Localization in somatic sensory and motor areas of human cerebral cortex as determined by direct recording of evoked potentials and electrical stimulation. J Neurosurg. 1979 Oct;51(4):476–506. doi: 10.3171/jns.1979.51.4.0476. [DOI] [PubMed] [Google Scholar]
  83. Yang T. T., Gallen C. C., Ramachandran V. S., Cobb S., Schwartz B. J., Bloom F. E. Noninvasive detection of cerebral plasticity in adult human somatosensory cortex. Neuroreport. 1994 Feb 24;5(6):701–704. doi: 10.1097/00001756-199402000-00010. [DOI] [PubMed] [Google Scholar]
  84. Yang T. T., Gallen C. C., Schwartz B. J., Bloom F. E. Noninvasive somatosensory homunculus mapping in humans by using a large-array biomagnetometer. Proc Natl Acad Sci U S A. 1993 Apr 1;90(7):3098–3102. doi: 10.1073/pnas.90.7.3098. [DOI] [PMC free article] [PubMed] [Google Scholar]
  85. Yousry T. A., Schmid U. D., Alkadhi H., Schmidt D., Peraud A., Buettner A., Winkler P. Localization of the motor hand area to a knob on the precentral gyrus. A new landmark. Brain. 1997 Jan;120(Pt 1):141–157. doi: 10.1093/brain/120.1.141. [DOI] [PubMed] [Google Scholar]
  86. Zhang H. Q., Murray G. M., Turman A. B., Mackie P. D., Coleman G. T., Rowe M. J. Parallel processing in cerebral cortex of the marmoset monkey: effect of reversible SI inactivation on tactile responses in SII. J Neurophysiol. 1996 Dec;76(6):3633–3655. doi: 10.1152/jn.1996.76.6.3633. [DOI] [PubMed] [Google Scholar]

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