Warner Tamara Duckworth, Behnke Marylou, Eyler Fonda Davis, Padgett Kyle, Leonard Christiana, Hou Wei, Garvan Cynthia Wilson, Schmalfuss Ilona M, Blackband Stephen J
University of Florida, College of Medicine, Department of Pediatrics, PO Box 100296, Gainesville, FL 32610-0296, USA.
Pediatrics. 2006 Nov;118(5):2014-24. doi: 10.1542/peds.2006-0003.
Although animal studies have demonstrated frontal white matter and behavioral changes resulting from prenatal cocaine exposure, no human studies have associated neuropsychological deficits in attention and inhibition with brain structure. We used diffusion tensor imaging to investigate frontal white matter integrity and executive functioning in cocaine-exposed children.
Six direction diffusion tensor images were acquired using a Siemens 3T scanner with a spin-echo echo-planar imaging pulse sequence on right-handed cocaine-exposed (n = 28) and sociodemographically similar non-exposed children (n = 25; mean age: 10.6 years) drawn from a prospective, longitudinal study. Average diffusion and fractional anisotropy were measured in the left and right frontal callosal and frontal projection fibers. Executive functioning was assessed using two well-validated neuropsychological tests (Stroop color-word test and Trail Making Test).
Cocaine-exposed children showed significantly higher average diffusion in the left frontal callosal and right frontal projection fibers. Cocaine-exposed children were also significantly slower on a visual-motor set-shifting task with a trend toward lower scores on a verbal inhibition task. Controlling for gender and intelligence, average diffusion in the left frontal callosal fibers was related to prenatal exposure to alcohol and marijuana and an interaction between cocaine and marijuana exposure. Performance on the visual-motor set-shifting task was related to prenatal cocaine exposure and an interaction between cocaine and tobacco exposure. Significant correlations were found between test performance and fractional anisotropy in areas of the frontal white matter.
Prenatal cocaine exposure, alone and in combination with exposure to other drugs, is associated with slightly poorer executive functioning and subtle microstructural changes suggesting less mature development of frontal white matter pathways. The relative contribution of postnatal environmental factors, including characteristics of the caregiving environment and stressors associated with poverty and out-of-home placement, on brain development and behavioral functioning in polydrug-exposed children awaits further research.
尽管动物研究已证明产前接触可卡因会导致额叶白质和行为改变，但尚无人体研究将注意力和抑制方面的神经心理学缺陷与脑结构联系起来。我们使用扩散张量成像来研究接触可卡因儿童的额叶白质完整性和执行功能。
使用西门子3T扫描仪，通过自旋回波平面成像脉冲序列，对来自一项前瞻性纵向研究的右利手接触可卡因儿童（n = 28）和社会人口统计学特征相似的未接触儿童（n = 25；平均年龄：10.6岁）采集六个方向的扩散张量图像。测量左右额叶胼胝体和额叶投射纤维的平均扩散率和各向异性分数。使用两项经过充分验证的神经心理学测试（斯特鲁普颜色词测试和连线测验）评估执行功能。
接触可卡因的儿童在左侧额叶胼胝体和右侧额叶投射纤维中的平均扩散率显著更高。在视觉运动转换任务中，接触可卡因的儿童也明显更慢，在言语抑制任务上得分有降低趋势。在控制性别和智力后，左侧额叶胼胝体纤维的平均扩散率与产前接触酒精和大麻以及可卡因与大麻接触之间的相互作用有关。视觉运动转换任务的表现与产前接触可卡因以及可卡因与烟草接触之间的相互作用有关。在额叶白质区域，测试表现与各向异性分数之间存在显著相关性。
产前接触可卡因，单独或与接触其他药物一起，与执行功能略差以及细微的微观结构变化有关，这表明额叶白质通路的发育不太成熟。产后环境因素，包括照料环境的特征以及与贫困和家庭外安置相关的压力源，对多药接触儿童脑发育和行为功能的相对贡献有待进一步研究。
