National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20892, USA.
Cereb Cortex. 2011 Sep;21(9):2003-13. doi: 10.1093/cercor/bhq268. Epub 2011 Jan 31.
Functional networks are usually accessed with "resting-state" functional magnetic resonance imaging using preselected "seeds" regions. Frequently, however, the selection of the seed locations is arbitrary. Recently, we proposed local functional connectivity density mapping (FCDM), an ultrafast data-driven to locate highly connected brain regions (functional hubs). Here, we used the functional hubs obtained from local FCDM to determine the functional networks of the resting state in 979 healthy subjects without a priori hypotheses on seed locations. In addition, we computed the global functional connectivity hubs. Seven networks covering 80% of the gray matter volume were identified. Four major cortical hubs (ventral precuneus/posterior cingulate, inferior parietal cortex, cuneus, and postcentral gyrus) were linked to 4 cortical networks (default mode, dorsal attention, visual, and somatosensory). Three subcortical networks were associated to the major subcortical hubs (cerebellum, thalamus, and amygdala). The networks differed in their resting activity and topology. The higher coupling and overlap of subcortical networks was associated to higher contribution of short-range functional connectivity in thalamus and cerebellum. Whereas cortical local FCD hubs were also hubs of long-range connectivity, which corroborates the key role of cortical hubs in network architecture, subcortical hubs had minimal long-range connectivity. The significant variability among functional networks may underlie their sensitivity/resilience to neuropathology.
功能网络通常使用预先选择的“种子”区域进行“静息状态”功能磁共振成像来访问。然而，种子位置的选择通常是任意的。最近，我们提出了局部功能连接密度映射（FCMD），这是一种超快的数据驱动方法，用于定位高度连接的脑区（功能枢纽）。在这里，我们使用局部 FCMD 获得的功能枢纽来确定 979 名健康受试者在没有种子位置先验假设的静息状态下的功能网络。此外，我们计算了全局功能连接枢纽。确定了覆盖 80%灰质体积的 7 个网络。四个主要的皮质枢纽（腹侧后扣带回/后扣带回、下顶叶皮层、楔前叶和后中央回）与 4 个皮质网络（默认模式、背侧注意、视觉和躯体感觉）相关联。三个皮质下网络与主要皮质下枢纽（小脑、丘脑和杏仁核）相关联。这些网络在静息活动和拓扑结构上存在差异。皮质下网络的耦合和重叠越高，与丘脑和小脑中短程功能连接的贡献越高。虽然皮质局部 FCD 枢纽也是长程连接的枢纽，但这证实了皮质枢纽在网络结构中的关键作用，而皮质下枢纽的长程连接则很少。功能网络之间的显著可变性可能是其对神经病理学的敏感性/弹性的基础。
