Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Department of Neurology, West China Hospital of Sichuan University, Chengdu, China.
Epilepsy Res. 2014 Jan;108(1):125-38. doi: 10.1016/j.eplepsyres.2013.10.002. Epub 2013 Oct 21.
The structural connection patterns of the human brain are the underlying bases for functional connectivity. Although abnormal functional connectivity has been uncovered in childhood absence epilepsy (CAE) in previous electroencephalography and functional magnetic resonance imaging studies, little is known regarding the structural connectivity in CAE. We hypothesized that the structural connectivity would be disrupted in response to the decreased brain function in CAE.
Diffusion tensor imaging tractography was utilized to map the white matter (WM) structural network, composed of 90 cortical and sub-cortical regions, in 18 CAE and 18 age- and gender-matched healthy controls. Graph theoretical methods were applied to investigate the alterations in the topological and nodal properties of the networks in these patients.
Both the CAE and the controls showed small-world properties in their WM networks. However, the network connection strength, absolute clustering coefficient, and global/local efficiency were significantly decreased, but characteristic path length was significantly increased in the CAE compared with the controls. Significantly decreased WM connections, nodal properties, and impaired sub-networks were found in the sub-cortical structures, orbitofrontal area, and limbic cortex in the CAE. Moreover, network connection strength, local efficiency, and nodal features in some regions were significantly negatively correlated with the duration of epilepsy.
The present study demonstrated, for the first time, the disrupted topological organization of WM networks in CAE. The decreased connectivity and efficiency in the orbitofrontal and sub-cortical regions may serve as anatomical evidence to support the functional abnormalities related to the epileptic discharges observed in CAE. Moreover, the orbitofrontal sub-network may play a key role in CAE. These findings open up new avenues toward the understanding of absence epilepsy.
人类大脑的结构连接模式是功能连接的基础。尽管以前的脑电图和功能磁共振成像研究已经发现了儿童失神癫痫（CAE）中的异常功能连接，但对于 CAE 中的结构连接知之甚少。我们假设结构连接会因 CAE 中大脑功能下降而中断。
利用弥散张量成像束追踪技术，对 18 例 CAE 和 18 例年龄和性别匹配的健康对照者的 90 个皮质和皮质下区域的白质（WM）结构网络进行了绘图。应用图论方法研究了这些患者网络中拓扑和节点属性的变化。
CAE 和对照组的 WM 网络均表现出小世界特性。然而，与对照组相比，CAE 中的网络连接强度、绝对聚类系数和全局/局部效率显著降低，但特征路径长度显著增加。在 CAE 中发现 WM 连接、节点属性和受损子网络明显减少，这些改变发生在皮质下结构、眶额区和边缘皮层。此外，一些区域的网络连接强度、局部效率和节点特征与癫痫持续时间呈显著负相关。
本研究首次证明了 CAE 中 WM 网络的拓扑组织中断。眶额和皮质下区域连接的减少和效率的降低可能为支持与 CAE 中观察到的癫痫放电相关的功能异常提供解剖学证据。此外，眶额子网可能在 CAE 中发挥关键作用。这些发现为理解失神癫痫开辟了新的途径。
