Neuroimaging Research Unit, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
Neurology. 2013 Jul 9;81(2):134-43. doi: 10.1212/WNL.0b013e31829a33f8. Epub 2013 May 29.
To investigate whether brain functional network connectivity is disrupted in patients with the behavioral variant of frontotemporal dementia (bvFTD).
Graph theoretical analysis was applied to resting state functional MRI data from 18 patients with probable bvFTD and 50 healthy individuals. Functional connectivity between 90 cortical and subcortical brain regions was estimated using bivariate correlation analysis and thresholded to construct a set of undirected graphs. Correlations between network properties and cognitive variables were tested.
Global topologic organization of the functional brain network in bvFTD was significantly disrupted as indicated by reduced mean network degree, clustering coefficient, and global efficiency and increased characteristic path length and assortativity relative to normal subjects. Compared to controls, bvFTD data showed retention of major "hub" regions in the medial parietal, temporal, and occipital lobes, but cortical hubs were not noted in the frontal lobes. Medial and dorsal frontal regions, left caudate nucleus, left insular cortices, and some regions of the temporal, parietal, and occipital lobes showed decreased nodal centrality. BvFTD patients showed the greatest decrease in inter-regional connectivity between the frontal and occipital regions, and the insular cortices and occipital, temporal, subcortical, and frontal regions. In bvFTD, altered global network properties correlated with executive dysfunction.
Global and local functional networks are altered in bvFTD, suggesting a loss of efficiency in information exchange between both distant and close brain areas. Altered brain regions are located in structures that are closely associated with neuropathologic changes in bvFTD. Aberrant topology of the functional brain networks in bvFTD appears to underlie cognitive deficits in these patients.
研究行为变异额颞叶痴呆（bvFTD）患者的脑功能网络连接是否中断。
对 18 例可能患有 bvFTD 的患者和 50 名健康个体的静息状态功能磁共振成像数据进行图论分析。使用二元相关分析估计 90 个皮质和皮质下脑区之间的功能连接，并将其阈值化以构建一组无向图。测试网络特性与认知变量之间的相关性。
与正常受试者相比，bvFTD 患者的脑功能网络全局拓扑组织明显受损，表现为平均网络度、聚类系数和全局效率降低，特征路径长度和聚类系数增加。与对照组相比，bvFTD 数据保留了内侧顶叶、颞叶和枕叶的主要“枢纽”区域，但额叶中没有皮质枢纽。额叶、背侧额叶、左侧尾状核、左侧岛叶皮质以及颞叶、顶叶和枕叶的一些区域节点中心性降低。bvFTD 患者的额叶和枕叶、岛叶皮质以及枕叶、颞叶、皮质下和额叶之间的区域间连接减少最为明显。在 bvFTD 中，改变的全局网络特性与执行功能障碍相关。
bvFTD 中存在全局和局部功能网络改变，提示信息在远近脑区之间的交换效率降低。改变的脑区位于与 bvFTD 神经病理学变化密切相关的结构中。bvFTD 患者的功能脑网络拓扑异常似乎是这些患者认知缺陷的基础。
