Roos Annerine, Kwiatkowski Maja A, Fouche Jean-Paul, Narr Katherine L, Thomas Kevin G F, Stein Dan J, Donald Kirsty A
SU/UCT MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, PO Box 19063, Tygerberg 7505, South Africa.
University of Cape Town, Department of Psychology, South Africa.
Behav Brain Res. 2015 Feb 15;279:62-7. doi: 10.1016/j.bbr.2014.11.005. Epub 2014 Nov 12.
There is emerging evidence on the harmful effects of prenatal methamphetamine (MA) exposure on the structure and function of the developing brain. However, few studies have assessed white matter structural integrity in the presence of prenatal MA exposure, and results are inconsistent. This investigation thus used diffusion tensor imaging (DTI) to investigate white matter microstructure and cognitive performance in a group of prenatal MA exposed (or MA) children and controls of similar age. Seventeen MA children and 15 healthy controls (aged 6-7 years) underwent DTI and assessment of motor function and general cognitive ability. Whole brain analyses of white matter structure were performed using FSL's tract-based spatial statistics comparing fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Mean diffusion values were extracted from white matter regions shown to differ across groups to determine whether variations in FA predicted cognitive performance. Analyses were controlled for maternal nicotine use. MA children showed significantly lower FA as well as higher MD, RD and AD in tracts that traverse striatal, limbic and frontal regions. Abnormal FA levels in MA children were significantly associated with poorer motor coordination and general cognitive ability sub-items that relate to aspects of executive function. Our findings suggest that, consistent with previous studies in older children, there are disruptions of white matter microstructural integrity in striatal, limbic and frontal regions of young MA exposed children, with prominent cognitive implications. Future longitudinal studies may clarify how prenatal MA exposure affects white matter structural connectivity at different stages of brain maturation.
有新证据表明，产前接触甲基苯丙胺（MA）会对发育中大脑的结构和功能产生有害影响。然而，很少有研究评估产前接触MA情况下的白质结构完整性，且结果并不一致。因此，本研究采用扩散张量成像（DTI）来调查一组产前接触MA（或MA组）儿童及年龄相仿的对照组儿童的白质微观结构和认知表现。17名MA组儿童和15名健康对照组儿童（年龄6 - 7岁）接受了DTI检查，并对运动功能和一般认知能力进行了评估。使用FSL基于纤维束的空间统计学方法对白质结构进行全脑分析，比较分数各向异性（FA）、平均扩散率（MD）、径向扩散率（RD）和轴向扩散率（AD）。从显示出组间差异的白质区域提取平均扩散值，以确定FA的变化是否能预测认知表现。分析中对母亲使用尼古丁的情况进行了控制。MA组儿童在穿过纹状体、边缘系统和额叶区域的纤维束中，FA显著降低，而MD、RD和AD则升高。MA组儿童异常的FA水平与较差的运动协调性以及与执行功能方面相关的一般认知能力子项目显著相关。我们的研究结果表明，与之前对大龄儿童的研究一致，产前接触MA的年幼儿童的纹状体、边缘系统和额叶区域存在白质微观结构完整性破坏，并具有明显的认知影响。未来的纵向研究可能会阐明产前接触MA如何在大脑成熟的不同阶段影响白质结构连接性。
