Sibilia Francesca, Kehoe Elizabeth G, Farrell Dervla, Kerskens Christian, O'Neill Desmond, McNulty Jonathan P, Mullins Paul, Bokde Arun L W
1 Trinity College Institute of Neuroscience and Cognitive Systems Group , Discipline of Psychiatry, School of Medicine, Trinity College Dublin, Dublin, Ireland .
2 Trinity College Institute of Neuroscience , Dublin, Ireland .
Brain Connect. 2017 Aug;7(6):366-372. doi: 10.1089/brain.2017.0493.
The aim of this study was to investigate the aging-related structural changes of the cingulum, one of the major components of the limbic network, which has a critical role in emotion, attention, and memory. Thirty-five healthy young adults (22.3 ± 2.7 years) and 33 healthy older adults (69.5 ± 3.5 years) were recruited. Diffusion weighted imaging data were acquired with a b-value = 2000 sec/mm and 61 diffusion directions and 4 non-weighted images. The fiber directions in each voxel were based on the constrained spherical deconvolution model. The cingulum was segmented into three branches using deterministic tractography (subgenual, retrosplenial, and parahippocampal), using a region-of-interest-based approach. Atlas-based tractography was the method used to obtain the output tracts of each branch of the cingulum. Along-tract analysis was performed on each branch. We found a statistically significant change with aging in the left subgenual branch of the cingulum with a decrease in fractional anisotropy and axial diffusivity, as well as an increase in radial diffusivity. No statistically significant differences were found between young and older groups in the other two branches. This study adds to knowledge about how the cingulum changes structurally along its entire length during aging in a more detailed way, thanks to an advanced methodological approach.
本研究的目的是调查扣带束（边缘网络的主要组成部分之一，在情感、注意力和记忆方面起着关键作用）与衰老相关的结构变化。招募了35名健康的年轻成年人（22.3±2.7岁）和33名健康的老年人（69.5±3.5岁）。采用b值=2000秒/毫米、61个扩散方向和4幅非加权图像采集扩散加权成像数据。每个体素中的纤维方向基于约束球形反卷积模型。使用基于感兴趣区域的方法，通过确定性纤维束成像将扣带束分为三个分支（膝下、扣带回后和海马旁）。基于图谱的纤维束成像用于获取扣带束每个分支的输出纤维束。对每个分支进行纤维束沿线分析。我们发现，扣带束左膝下分支随年龄增长有统计学意义的变化，表现为各向异性分数和轴向扩散率降低，以及径向扩散率增加。在其他两个分支中，年轻组和老年组之间未发现统计学显著差异。由于采用了先进的方法，本研究以更详细的方式增加了关于扣带束在衰老过程中沿其全长结构如何变化的知识。
