Department of Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
Department of Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
Neuropsychologia. 2021 Oct 15;161:108001. doi: 10.1016/j.neuropsychologia.2021.108001. Epub 2021 Aug 24.
For 8 years, we have followed up a birth cohort comprising 241 mother-and-infant pairs living around the Da Nang airbase, a hot spot of dioxin contamination in Vietnam, and have reported the impacts of perinatal dioxin exposure on the neurodevelopment of children at various ages. In the present study, 9 years after birth, we investigated the effects of perinatal dioxin exposure on mu and theta rhythms by analyzing EEG power during the execution and observation of hand movements, which indicate mirror neuron system activity.
One hundred fifty-five 9-year-old children (86 boys and 69 girls) from the Da Nang birth cohort participated in the EEG examination with free viewing of hand movements. The dioxin levels in their mothers' breast milk, measured 1 month after birth, were used as perinatal dioxin exposure markers. A log transform of the ratio of EEG power during execution or observation of the hand movements relative to the power during observation of a bouncing ball for theta and mu rhythms was used to evaluate mirror neuron activity.
In both brain hemispheres, the log power ratio in the theta band was significantly higher (i.e., less reduction of power) during observation of hand movements in girls exposed to high levels of TCDD. In boys, however, dioxin congeners other than TCDD, including HxCDDs and several PCDF congeners, contributed to increased log power ratios in the theta band. Particularly for PCDF congeners, the log power ratios in the lowest group among 4 exposure groups were lowest and significantly increased (i.e., decreasing reduction of power) with increasing dose.
Perinatal TCDD exposure may influence the mirror neuron system of the brain, which plays an important role for social-emotional behavior in children, particularly in girls living in a hot spot of dioxin contamination in Vietnam.
8 年来，我们一直对生活在越南岘港空军基地周围的一个二恶英污染热点地区的 241 对母婴进行了随访，并报告了围产期二恶英暴露对儿童各个年龄段神经发育的影响。在本研究中，在出生后 9 年，我们通过分析执行和观察手部运动时的脑电图功率，研究了围产期二恶英暴露对μ和θ节律的影响，这表明了镜像神经元系统的活动。
155 名 9 岁的岘港出生队列儿童（86 名男孩和 69 名女孩）参与了手部运动自由观察的 EEG 检查。在出生后 1 个月测量了他们母亲母乳中二恶英的水平，作为围产期二恶英暴露的标志物。使用执行或观察手部运动时的 EEG 功率与观察弹球时的功率之比的对数变换来评估镜像神经元的活动。
在两个大脑半球中，在高水平 TCDD 暴露的女孩中，观察手部运动时θ波段的对数功率比显著更高（即功率降低较小）。然而，在男孩中，除 TCDD 以外的二恶英同系物，包括 HxCDDs 和几种 PCDF 同系物，导致θ波段的对数功率比增加。特别是对于 PCDF 同系物，在 4 个暴露组中最低组的对数功率比最低，并且随着剂量的增加而显著增加（即功率降低减少）。
围产期 TCDD 暴露可能会影响大脑的镜像神经元系统，这对儿童的社会情感行为起着重要作用，特别是对生活在越南二恶英污染热点地区的女孩。
