From the Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, United States.
ACSENT Laboratory, Department of Psychology, University of Cape Town, Cape Town, South Africa.
Alcohol Clin Exp Res. 2020 Apr;44(4):844-855. doi: 10.1111/acer.14310. Epub 2020 Mar 20.
Prenatal alcohol exposure (PAE) has been linked to poorer performance on the Morris water maze (MWM), a test of spatial navigation in rodents that is dependent on hippocampal functioning. We recently confirmed these findings in children with PAE on a human analog of the MWM, the virtual water maze (VWM). Previous studies have shown that the hippocampus is particularly sensitive to PAE. Our aim was to determine whether hippocampal volume mediates the relation between PAE and virtual navigation.
VWM and MRI hippocampal data were collected from 50 right-handed 10-year-old children in a heavily exposed Cape Town, South African sample. PAE data had been collected from their mothers during pregnancy, and the children were examined by expert fetal alcohol spectrum disorder (FASD) dysmorphologists. In the VWM, the participant attempts to learn the location of a hidden platform in a virtual pool of water across a series of learning trials using only distal room cues. Hippocampal volumes were derived using FreeSurfer from MRI scans administered within 1 week of completing the VWM task.
Both the fetal alcohol syndrome (FAS)/partial FAS and nonsyndromal heavy-exposed (HE) groups had smaller hippocampal volumes than controls. PAE was associated with reduced right hippocampal volumes even after control for total intracranial volume (ICV). Hippocampal volume was also positively associated with VWM performance. The relation between PAE and VWM performance was partially mediated by right hippocampal volume but not by total ICV.
These data confirm previous reports linking PAE to poorer spatial navigation on the VWM and are the first to provide direct evidence that volume reductions in this region partially mediate the relation of FASD diagnosis to place learning, suggesting that PAE specifically impairs the ability to encode the spatial information necessary for successful location of the hidden platform on a navigation task.
产前酒精暴露 (PAE) 与在啮齿动物中依赖海马功能的空间导航任务——水迷宫 (MWM) 上表现较差有关。我们最近在使用 MWM 人类模拟物——虚拟水迷宫 (VWM) 的 PAE 儿童中证实了这些发现。先前的研究表明，海马体对 PAE 特别敏感。我们的目的是确定海马体体积是否介导了 PAE 与虚拟导航之间的关系。
在一个南非开普敦重度暴露的样本中，从 50 名右利手 10 岁儿童中收集了 VWM 和 MRI 海马体数据。PAE 数据是从他们的母亲在怀孕期间收集的，并且这些孩子由专家胎儿酒精谱系障碍 (FASD) 畸形学家进行了检查。在 VWM 中，参与者在一系列学习试验中仅使用远距离房间线索，试图在虚拟水池中找到隐藏平台的位置。在完成 VWM 任务后的 1 周内，使用 FreeSurfer 从 MRI 扫描中得出海马体体积。
FAS/部分 FAS 和非综合征重度暴露 (HE) 组的海马体体积均小于对照组。即使控制了总颅内体积 (ICV)，PAE 也与右海马体体积减少有关。海马体体积与 VWM 表现呈正相关。PAE 与 VWM 表现之间的关系部分由右海马体体积介导，但不受总 ICV 影响。
这些数据证实了之前的报告，即 PAE 与 VWM 上较差的空间导航有关，并且是第一个提供直接证据表明该区域的体积减少部分介导了 FASD 诊断与位置学习之间的关系，表明 PAE 特异性地损害了在导航任务中成功定位隐藏平台所需的空间信息编码能力。
