単音節聴取時の聴覚野の反応 -functional MRIを用いた検討-  [in Japanese] Auditory Cortical Response to Monaural Stimulation as Detected by Functional Magnetic Resonance Imaging  [in Japanese]

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Abstract

音刺激の聴覚野への交叉性投射を調べる目的で単音節刺激時の聴覚野脳活動をfunctional MRIを用いて検討した.対象は聴力正常な成人6名(右利き)である.1秒間に1個の単音節(95dBSPL)を呈示し,OFF-ONパラダイム(OFF;音刺激なし,20秒,ON;音刺激あり,20秒)を4回繰り返した.機能画像は1.5テスラMRI装置(GE社製Signa Horizon)でグラジエントエコーエコープラナー画像(EPI)として得た.EPIはワークステーション上でSPM99bを使用し解析を行い,聴覚野賦活部位を測定した.<br>予備実験としてEPI撮像時の騒音を測定した.ERI撮像時の騒音は97dBSPLであったが,MR対応のヘッドホンを使用することにより80dBSPLまで減少させることが可能であった.片耳単音節刺激により主に反対側の1次聴覚野,両側の聴覚連合野に広い賦活部位が観察された.賦活は一次聴覚野より聴覚連合野に著明であった.右耳に単音節刺激を与えた際は左聴覚野に,左耳に与えた際は右聴覚野に有意に広い賦活部位がみられた.このパターンは被験者全員に観察された.この結果から単音節聴取時の音情報は両側の聴覚野に入力されるが,刺激対側の聴覚野に反応が強く交叉性投射が確認された.撮像時の騒音を減少させれば聴覚刺激による反応をfunctional MRIで測定することが可能であり今後臨床応用できると結論した.

In order to confirm the crossed-innervation between auditory cortex and the ear that receives monosyllabic sound, the auditory cortical response to monaural monosyllabic stimulation as detected by functional magnetic resonance imaging (fMRI) was investigated in six normal hearing subjects. Stimulus amplitude averaged 95 dBSPL at the distal end of the audio system. A series of 440 echo planar images was acquired during the acoustic stimulation within the four OFF-ON cycle paradigm. Five image series with 10 slices were collected within each OFF or On period. Each scanning session began with four baseline images before the OFF-ON paradigm. Monosyllabic sounds were presented monaurally duritng the ON period at a rate of one monosyllable/sec. Functional MRI data were analyzed with SPM99b software (Statistical Parametric Mapping). <br>The background scanner noise averaged 97dBSPL. The selicon ear plug and headphone as acoustic shields attenuated the noise as much as 17dB. A broad and intense auditory cortical response was observed bilaterally in response to monaural monosyllable stimulation. Sound presentation to the right ear was followed by a larger response in the left auditory cortex than in the right, and left ear stimulation evoked a larger response in the right auditory cortex than in the left. This pattern was consistent in all subjects examined. The primary auditory cortex responded to monosyllabic words presented to the contralateral ear. The results confirmed the crossed-innervation between the auditory cortex and ear for listening to monosyllables. Functional MRI is a useful tool for investigating auditory cortex function, if the scanner noise is adequated controlled.

Journal

  • Nippon Jibiinkoka Gakkai Kaiho

    Nippon Jibiinkoka Gakkai Kaiho 103(8), 879-884, 2000-08-20

    The Oto-Rhino-Laryngological Society of Japan, Inc.

References:  11

Cited by:  2

Codes

  • NII Article ID (NAID)
    10005594923
  • NII NACSIS-CAT ID (NCID)
    AN00191551
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    00306622
  • Data Source
    CJP  CJPref  J-STAGE 
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