Somatosensory mechanical response and digit somatotopy within cortical areas of the postcentral gyrus in humans: An MEG study

Authors

  • Ken Inoue,

    Corresponding author
    1. Department of Neurology, Hiroshima Prefectural Hospital, Minami-ku, Hiroshima, Japan
    • Department of Neurology, Hiroshima Prefectural Hospital, 1-5-54 Ujinakanda, Minami-ku, Hiroshima 734-8530, Japan
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  • Kazuyoshi Nakanishi,

    1. Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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  • Hikmat Hadoush,

    1. Department of Rehabilitation of Locomotor System Dysfunction, Graduate School of Health Science, Hiroshima University, Minami-ku, Hiroshima, Japan
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  • Hiroshi Kurumadani,

    1. Department of Rehabilitation of Locomotor System Dysfunction, Graduate School of Health Science, Hiroshima University, Minami-ku, Hiroshima, Japan
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  • Akira Hashizume,

    1. Department of Neurosurgery, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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  • Toru Sunagawa,

    1. Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
    2. Department of Rehabilitation of Locomotor System Dysfunction, Graduate School of Health Science, Hiroshima University, Minami-ku, Hiroshima, Japan
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  • Mitsuo Ochi

    1. Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan
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Abstract

Somatosensory evoked fields in response to compression (termed as Co) and decompression (termed as De) of glabrous skin (D1, thumb; D2, index finger; D5, little finger) were recorded. Although estimated equivalent current dipoles (ECDs) following stimulation of D1 and D5 were larger, but not significantly larger, in decompression than in compression, those of D2 were significantly larger (P = 0.035). The ECDs were located in the postcentral gyrus in the order of D5De, D2De, and D1De medially, posteriorly, and superiorly in decompression but not in compression (z-value, F = 2.692, P = 0.031). The average distance of ECDs between D1 and D5 was longer in decompression (12.8 ± 1.6 mm) than in compression (9.1 ± 1.6 mm). Our data suggest that the cortical response for the commonly used digit D2 is functionally different from those for other digits (D1 and D5) that the somatotopic variability is greater in compression. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.

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