Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA.
Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA.
Sci Rep. 2017 Aug 18;7(1):8749. doi: 10.1038/s41598-017-08107-6.
Anxiety is linked to deficits in structural and functional connectivity between limbic structures and pre-frontal cortices. We employed a monozygotic (MZ) twin difference design to examine the relationship between structural characteristics of the uncinate fasciculus (UF) measured by Diffusion Tensor Imaging (DTI) and anxiety symptoms in a sample of N = 100 monozygotic (genetically identical), adolescent twins. The MZ difference design allowed us focus on environmental factors that vary within twin pairs while controlling for genetic and environmental factors shared by twin pairs. Twins aged 13-18 years reported on symptoms of generalized anxiety and social phobia prior to participating in a neuroimaging visit. Regions of interest from the JHU ICBM atlas, including uncinate fasciculus and sagittal stratum as a control tract, were registered to the study template. We incorporated multiple diffusion tensor measures to characterize the white matter differences. Within twin pairs, the more anxious twin exhibited decreased fractional anisotropy (t = -2.22, p = 0.032) and axial diffusivity (t = -2.38, p = 0.022) in the left UF compared to the less anxious twin, controlling for age and gender. This study demonstrated the feasibility and advantages of adopting the MZ twin design for DTI measures in neuroimaging research.
焦虑与边缘结构和前额皮质之间的结构和功能连接缺陷有关。我们采用单卵（MZ）双胞胎差异设计，来研究弥散张量成像（DTI）测量的钩束结构特征与 100 名单卵（遗传上相同）青少年双胞胎焦虑症状之间的关系。MZ 双胞胎差异设计使我们能够专注于双胞胎个体内变化的环境因素，同时控制双胞胎个体间共享的遗传和环境因素。13-18 岁的双胞胎在参加神经影像学检查之前报告了广泛性焦虑和社交恐惧症的症状。从 JHU ICBM 图谱中选取感兴趣区域，包括钩束和矢状层作为对照束，注册到研究模板中。我们采用了多种弥散张量测量方法来描述白质差异。在双胞胎个体内，与不那么焦虑的双胞胎相比，更焦虑的双胞胎左钩束的各向异性分数（FA）（t=-2.22，p=0.032）和轴向弥散度（AD）（t=-2.38，p=0.022）降低，控制了年龄和性别。这项研究证明了采用 MZ 双胞胎设计进行神经影像学研究中 DTI 测量的可行性和优势。
