Department of Human Biology, University of Cape Town Faculty of Health Sciences, South Africa. bspotty@gmail
Alcohol Clin Exp Res. 2011 Dec;35(12):2174-83. doi: 10.1111/j.1530-0277.2011.01566.x. Epub 2011 Jul 25.
Prenatal alcohol exposure is related to a wide range of neurocognitive effects. Eyeblink conditioning (EBC), which involves temporal pairing of a conditioned with an unconditioned stimulus, has been shown to be a potential biomarker of fetal alcohol exposure. A growing body of evidence suggests that white matter may be a specific target of alcohol teratogenesis, and the neural circuitry underlying EBC is known to involve the cerebellar peduncles. Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that has proven useful for assessing central nervous system white matter integrity. This study used DTI to examine the degree to which the fetal alcohol-related deficit in EBC may be mediated by structural impairment in the cerebellar peduncles.
Thirteen children with fetal alcohol spectrum disorder (FASD) and 12 matched controls were scanned using DTI and structural MRI sequences. The DTI data were processed using a voxelwise technique, and the structural data were used for volumetric analyses. Prenatal alcohol exposure group and EBC performance were examined in relation to brain volumes and outputs from the DTI analysis.
Fractional anisotropy (FA) and perpendicular diffusivity group differences between alcohol-exposed and nonexposed children were identified in the left middle cerebellar peduncle. Alcohol exposure correlated with lower FA and greater perpendicular diffusivity in this region, and these correlations remained significant even after controlling for total brain and cerebellar volumes. Conversely, trace conditioning performance was related to higher FA and lower perpendicular diffusivity in the left middle peduncle. The effect of prenatal alcohol exposure on trace conditioning was partially mediated by lower FA in this region.
This study extends recent findings that have used DTI to reveal microstructural deficits in white matter in children with FASD. This is the first DTI study to demonstrate mediation of a fetal alcohol-related effect on neuropsychological function by deficits in white matter integrity.
产前酒精暴露与广泛的神经认知效应有关。眨眼条件反射（EBC）涉及条件刺激与非条件刺激的时间配对，已被证明是胎儿酒精暴露的潜在生物标志物。越来越多的证据表明，白质可能是酒精致畸的特定靶标，而 EBC 的神经回路已知涉及小脑脚。弥散张量成像（DTI）是一种磁共振成像（MRI）技术，已被证明可用于评估中枢神经系统白质的完整性。本研究使用 DTI 检查 EBC 中与胎儿酒精相关的缺陷是否可能由小脑脚的结构损伤介导。
13 名患有胎儿酒精谱系障碍（FASD）的儿童和 12 名匹配的对照组使用 DTI 和结构 MRI 序列进行扫描。使用体素技术处理 DTI 数据，并使用结构数据进行容积分析。检查了产前酒精暴露组和 EBC 表现与脑体积和 DTI 分析结果之间的关系。
在左中小脑脚中发现了酒精暴露和未暴露儿童之间的各向异性分数（FA）和垂直扩散差异。在该区域，酒精暴露与 FA 降低和垂直扩散增加相关，即使在控制总脑和小脑体积后，这些相关性仍然显著。相反，痕迹条件反射表现与左中小脑脚中更高的 FA 和更低的垂直扩散相关。产前酒精暴露对痕迹条件反射的影响部分由该区域 FA 降低介导。
本研究扩展了最近使用 DTI 揭示 FASD 儿童白质微观结构缺陷的发现。这是第一项证明白质完整性缺陷介导胎儿酒精相关对神经心理功能的影响的 DTI 研究。
