Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
Department of Neurology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
Neuroimage. 2020 Apr 15;210:116589. doi: 10.1016/j.neuroimage.2020.116589. Epub 2020 Jan 30.
Focal brain lesions disrupt resting-state functional connectivity, but the underlying structural mechanisms are unclear. Here, we examined the direct and indirect effects of structural disconnections on resting-state functional connectivity in a large sample of sub-acute stroke patients with heterogeneous brain lesions. We estimated the impact of each patient's lesion on the structural connectome by embedding the lesion in a diffusion MRI streamline tractography atlas constructed using data from healthy individuals. We defined direct disconnections as the loss of direct structural connections between two regions, and indirect disconnections as increases in the shortest structural path length between two regions that lack direct structural connections. We then tested the hypothesis that functional connectivity disruptions would be more severe for disconnected regions than for regions with spared connections. On average, nearly 20% of all region pairs were estimated to be either directly or indirectly disconnected by the lesions in our sample, and extensive disconnections were associated primarily with damage to deep white matter locations. Importantly, both directly and indirectly disconnected region pairs showed more severe functional connectivity disruptions than region pairs with spared direct and indirect connections, respectively, although functional connectivity disruptions tended to be most severe between region pairs that sustained direct structural disconnections. Together, these results emphasize the widespread impacts of focal brain lesions on the structural connectome and show that these impacts are reflected by disruptions of the functional connectome. Further, they indicate that in addition to direct structural disconnections, lesion-induced increases in the structural shortest path lengths between indirectly structurally connected region pairs provide information about the remote functional disruptions caused by focal brain lesions.
脑局灶性病变破坏静息状态功能连接，但潜在的结构机制尚不清楚。在这里，我们在亚急性卒中患者的大样本中研究了结构连接中断对静息状态功能连接的直接和间接影响，这些患者的脑损伤存在异质性。我们通过将病变嵌入使用健康个体数据构建的扩散 MRI 流线追踪图谱中，估计了每个患者病变对结构连接组的影响。我们将直接连接中断定义为两个区域之间直接结构连接的丧失，将缺乏直接结构连接的两个区域之间最短结构路径长度的增加定义为间接连接中断。然后，我们检验了以下假设：与具有保留连接的区域相比，功能连接中断在断开连接的区域中更为严重。平均而言，在我们的样本中，几乎 20%的所有区域对被估计为直接或间接断开连接，广泛的连接中断主要与深部白质位置的损伤有关。重要的是，直接和间接断开连接的区域对都比具有保留的直接和间接连接的区域对表现出更严重的功能连接中断，尽管功能连接中断往往在直接结构连接中断的区域对之间最为严重。总之，这些结果强调了局灶性脑病变对结构连接组的广泛影响，并表明这些影响反映在功能连接组的中断中。此外，它们表明，除了直接的结构连接中断之外，病变引起的间接结构连接的区域对之间的结构最短路径长度的增加，提供了有关局灶性脑病变引起的远程功能中断的信息。
