Department of Child and Adolescent Psychiatry, New York University Medical Center, New York, USA; Department of Population Health, New York University Medical Center, New York, NY, USA; Institute for Social Research, University of Michigan, Ann Arbor, MI, USA.
Department of Psychology, Wayne State University, Detroit, MI, USA.
Neuroimage. 2019 May 1;191:186-192. doi: 10.1016/j.neuroimage.2019.02.017. Epub 2019 Feb 7.
Lead represents a highly prevalent metal toxicant with potential to alter human biology in lasting ways. A population segment that is particularly vulnerable to the negative consequences of lead exposure is the human fetus, as exposure events occurring before birth are linked to varied and long-ranging negative health and behavioral outcomes. An area that has yet to be addressed is the potential that lead exposure during pregnancy alters brain development even before an individual is born. Here, we combine prenatal lead exposure information extracted from newborn bloodspots with the human fetal brain functional MRI data to assess whether neural network connectivity differs between lead-exposed and lead-naïve fetuses. We found that neural connectivity patterns differed in lead-exposed and comparison groups such that fetuses that were not exposed demonstrated stronger age-related increases in cross-hemispheric connectivity, while the lead-exposed group demonstrated stronger age-related increases in posterior cingulate cortex (PCC) to lateral prefrontal cortex (PFC) connectivity. These are the first results to demonstrate metal toxicant-related alterations in human fetal neural connectivity. Remarkably, the findings point to alterations in systems that support higher-order cognitive and regulatory functions. Objectives for future work are to replicate these results in larger samples and to test the possibility that these alterations may account for significant variation in future child cognitive and behavioral outcomes.
铅是一种普遍存在的重金属毒物，它有可能以持久的方式改变人类的生物学特性。特别容易受到铅暴露负面影响的人群是人类胎儿，因为出生前发生的暴露事件与各种长期的负面健康和行为结果有关。目前尚未解决的一个问题是，孕妇在怀孕期间接触铅是否会在个体出生前就改变大脑发育。在这里，我们将从新生儿血斑中提取的产前铅暴露信息与人类胎儿大脑功能磁共振成像数据相结合，以评估铅暴露胎儿和未暴露胎儿的神经网络连接是否存在差异。我们发现，铅暴露组和对照组的神经连接模式存在差异，未暴露组的胎儿在跨半球连接方面表现出更强的与年龄相关的增强，而铅暴露组在后扣带回皮层（PCC）到外侧前额叶皮层（PFC）的连接方面表现出更强的与年龄相关的增强。这些是首次证明金属毒物会改变人类胎儿神经连接的结果。值得注意的是，这些发现指向支持更高阶认知和调节功能的系统的改变。未来工作的目标是在更大的样本中复制这些结果，并测试这些改变是否可能导致未来儿童认知和行为结果的显著差异。
