Department of Radiology, University of California , San Francisco, San Francisco, California.
Brain Connect. 2016 Sep;6(7):548-57. doi: 10.1089/brain.2016.0431.
The edges of the structural connectome traverse the white matter to connect cortical and subcortical nodes, although the anatomic embedding of these edges is generally overlooked in the literature. Characterization of the geometry of the structural connectome could provide an improved understanding of the relative importance of various white matter regions to the network architecture of the human brain in normal development and aging, as well as in white matter diseases with regionally specific patterns of vulnerability. Edge density imaging (EDI) has previously been used to show that the posterior periventricular white matter contains a disproportionately large number of connectome edges. In this study, the regional distribution of connectome edges within cerebral white matter, including the importance of posterior periventricular white matter, is further investigated and demonstrated to be invariant to different gray matter parcellations and different diffusion MRI acquisition and postprocessing/tractography methods. An examination of the highest k-core edges and a virtual lesion analysis illuminate hemispheric asymmetries (left>right) in the embedding of connectome edges. Therefore, EDI reveals specific areas of vulnerability within the white matter connectivity of the human brain, especially in the periventricular white matter. The idea of a periventricular nexus fits with the known neurobiology of brain development and may result from simple geometrical considerations in minimizing wiring cost in structural brain connectivity.
结构连接组的边缘穿过白质连接皮质和皮质下节点，尽管这些边缘的解剖嵌入在文献中通常被忽视。结构连接组的几何特征的描述可以提供对正常发育和衰老过程中以及具有特定区域易损性的白质疾病中各种白质区域对人脑网络结构的相对重要性的更好理解。边缘密度成像（EDI）以前曾被用于表明后脑室周围白质包含不成比例数量的连接组边缘。在这项研究中，进一步研究和证明了脑白质内连接组边缘的区域分布，包括后脑室周围白质的重要性，这与不同的灰质分割以及不同的扩散 MRI 采集和后处理/轨迹追踪方法无关。对最高 k-核边缘的检查和虚拟病变分析阐明了连接组边缘嵌入的半球不对称性（左>右）。因此，EDI 揭示了人脑白质连接中的特定脆弱区域，特别是在脑室周围白质中。脑室周围枢纽的概念与大脑发育的已知神经生物学相吻合，并且可能源于结构大脑连接中最小化布线成本的简单几何考虑。
