研究のタイプ: 医学／生物学の研究 (experimental study)

[ファンクショナルMRIで測定されたヒトの脳活動に対する3000μTまでの60Hzの磁界ばく露] med./bio.

Effects of a 60 Hz magnetic field exposure up to 3000 µT on human brain activation as measured by functional magnetic resonance imaging

著者: Legros A, Modolo J, Brown S, Roberston J, Thomas AW
掲載誌: PLoS One 2015; 10 (7): e0132024-1-e0132024-27
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この研究は、ファンクショナルMRI（fMRI）を用いて、60Hzの磁界（MF）ばく露による運動および認知課題の遂行時のヒトの脳活動の変化を調べた。まず、少数の被験者（n=9）で、1800 μT MFを用いたパイロット実験を行い、fMRIによる脳活動の小さな変化の検出の実現可能性を実証した。次の本実験では、1) 指タッピング課題（n=21）、2) メンタルローテーション（二次元または三次元の物体を心的に回転させる能力）課題（n=21）を実施中の脳活動を測定した。課題遂行の前および後に、１時間の3000 μT MFばく露を与えた。その結果、MFばく露に引き続き実施した課題遂行で誘発された脳活動に有意な変化が見られた；ただし、課題の遂行成績への影響はなかった、と報告している。

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研究目的（著者による）

The effects of exposure of subjects to a 60 Hz magnetic field on the brain activity should be investigated using fMRI (remark EMF-Portal: the static magnetic field of the MRI was present during the whole session).

詳細情報

The study comprised two parts: a pilot study (n=5 exposure and n=4 sham exposure subjects) with a finger tapping task before and after 30 minutes of 60 Hz exposure, and the main study with a successive rest phase, finger tapping task (n=9 exposure and n=11 sham exposure subjects) and a mental rotation task (n=10 exposure and n=11 sham exposure subjects) before and after 60 minutes of 60 Hz exposure, respectively.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 60 Hz
ばく露時間: continuous for 30 minutes
pilot study
  • 磁束密度: 1.8 mT maximum (at the location of the cortex, 1 cm underneath the skull)
ばく露2: 60 Hz
ばく露時間: continuous for 60 minutes
main study
  • 磁束密度: 3 mT maximum (at the location of the cortex, 1 cm underneath the skull)

ばく露1

主たる特性
周波数 60 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 30 minutes
Additional information pilot study
ばく露装置
ばく露の発生源／構造
ばく露装置の詳細 subjects were placed in the MRI scanner in a head-first supine position with their heads gently restrained in a 12-channel phased array head coil lined with foam
Sham exposure A sham exposure was conducted.
Additional information an audio clip mimicking the sound of the 60 Hz MF was played in the experimental room during sham exposure to ensure similar experimental conditions
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 1.8 mT maximum - - at the location of the cortex, 1 cm underneath the skull
Additional parameter details

1.5 T static field of fMRI was present during exposure (co-exposure)

ばく露2

主たる特性
周波数 60 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 60 minutes
Additional information main study
ばく露装置
ばく露の発生源／構造
ばく露装置の詳細 subjects were placed in the MRI scanner in a head-first supine position with their heads gently restrained in a 32-channel phased array head coil lined with foam
Sham exposure A sham exposure was conducted.
Additional information an audio clip mimicking the sound of the 60 Hz MF was played in the experimental room during sham exposure to ensure similar experimental conditions
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 3 mT maximum - - at the location of the cortex, 1 cm underneath the skull
Additional parameter details

3 T static field of fMRI was present during exposure (co-exposure)

Reference articles

ばく露を受けた生物:

方法 影響評価項目／測定パラメータ／方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露前
  • ばく露中
  • ばく露後

研究の主なアウトカム（著者による）

Both, in the pilot study as well as in the main study, and in all tasks, a significantly decreased activity was detected in the cortex and cerebellum after exposure in exposed subjects compared to sham exposed subjects.
No differences were found in the performance of the tasks between the groups, and subjects could not distinguish between exposure and sham exposure conditions.
The authors conclude that exposure of subjects to a combined static and 60 Hz magnetic field could modulate the brain activity.

研究の種別:

研究助成

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