Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec H3A 2B4 Canada.
Brain. 2012 Aug;135(Pt 8):2350-7. doi: 10.1093/brain/aws137. Epub 2012 Jun 4.
Magnetic resonance imaging methods that measure interregional brain signalling at rest have been advanced as powerful tools to probe organizational properties of functional networks. In drug-resistant temporal lobe epilepsy, resting functional magnetic resonance imaging studies have primarily employed region of interest approaches that preclude a comprehensive evaluation of large-scale functional interactions. In line with the distributed nature of structural damage in this condition, we set out to quantify connectivity across the entire range of resting networks. Furthermore, we assessed whether connectivity is driven by co-localized structural pathology. We obtained resting state, diffusion tensor and anatomical imaging data in 35 patients with temporal lobe epilepsy and 20 healthy subjects on a 3 T scanner. Resting state networks were identified using independent component analysis, which allows an objective whole-brain quantification of functional connectivity. We performed group comparisons before and after correcting for voxel-wise grey matter density. In addition, we identified voxel-wise associations between resting connectivity and white matter coherence indexed by fractional anisotropy. Compared with controls, patients showed altered (typically reduced) functional connectivity between the hippocampus, anterior temporal, precentral cortices and the default mode and sensorimotor networks. Reduced network integration of the hippocampus was explained by variations in grey matter density, while functional connectivity of the parahippocampus, and frontal and temporal neocortices showed atypical associations with white matter coherence within pathways carrying connections of these regions. Our multimodal imaging study suggests that in temporal lobe epilepsy, cortical atrophy and microstructural white matter damage impact functional resting connectivity.
静息状态下测量脑区间信号的磁共振成像方法已被广泛应用于探测功能网络的组织特性，成为一种强大的工具。在耐药性颞叶癫痫中，静息功能磁共振成像研究主要采用了基于感兴趣区的方法，这些方法排除了对大规模功能相互作用的全面评估。基于这种情况下结构损伤的分布式性质，我们着手量化整个静息网络的连接。此外，我们还评估了连接是否由局部结构病理学驱动。我们在 3T 扫描仪上获得了 35 例颞叶癫痫患者和 20 例健康对照者的静息状态、弥散张量和解剖成像数据。使用独立成分分析（Independent Component Analysis，ICA）识别静息状态网络，该方法允许对功能连接进行客观的全脑量化。我们在对体素灰度密度进行校正之前和之后进行了组间比较。此外，我们还确定了静息状态连接与由各向异性分数（fractional anisotropy，FA）索引的白质相干性之间的体素关联。与对照组相比，患者的海马体、前颞叶、中央前皮质与默认模式和感觉运动网络之间的功能连接发生了改变（通常是减少）。海马体网络整合减少的原因是灰质密度的变化，而海马旁回、额叶和颞叶新皮质的功能连接与这些区域连接的白质相干性呈非典型关联。我们的多模态成像研究表明，在颞叶癫痫中，皮质萎缩和白质微观结构损伤会影响功能静息连接。
