Warren David E, Power Jonathan D, Bruss Joel, Denburg Natalie L, Waldron Eric J, Sun Haoxin, Petersen Steven E, Tranel Daniel
Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA 52242;
Departments of Neurology.
Proc Natl Acad Sci U S A. 2014 Sep 30;111(39):14247-52. doi: 10.1073/pnas.1322173111. Epub 2014 Sep 15.
Hubs are network components that hold positions of high importance for network function. Previous research has identified hubs in human brain networks derived from neuroimaging data; however, there is little consensus on the localization of such hubs. Moreover, direct evidence regarding the role of various proposed hubs in network function (e.g., cognition) is scarce. Regions of the default mode network (DMN) have been frequently identified as "cortical hubs" of brain networks. On theoretical grounds, we have argued against some of the methods used to identify these hubs and have advocated alternative approaches that identify different regions of cortex as hubs. Our framework predicts that our proposed hub locations may play influential roles in multiple aspects of cognition, and, in contrast, that hubs identified via other methods (including salient regions in the DMN) might not exert such broad influence. Here we used a neuropsychological approach to directly test these predictions by studying long-term cognitive and behavioral outcomes in 30 patients, 19 with focal lesions to six "target" hubs identified by our approaches (high system density and participation coefficient) and 11 with focal lesions to two "control" hubs (high degree centrality). In support of our predictions, we found that damage to target locations produced severe and widespread cognitive deficits, whereas damage to control locations produced more circumscribed deficits. These findings support our interpretation of how neuroimaging-derived network measures relate to cognition and augment classic neuroanatomically based predictions about cognitive and behavioral outcomes after focal brain injury.
中枢是对网络功能具有高度重要地位的网络组件。先前的研究已经在源自神经成像数据的人类脑网络中识别出了中枢；然而，对于这些中枢的定位几乎没有达成共识。此外，关于各种提出的中枢在网络功能（如认知）中的作用的直接证据很少。默认模式网络（DMN）的区域经常被识别为脑网络的“皮质中枢”。基于理论依据，我们反对一些用于识别这些中枢的方法，并提倡采用将不同皮质区域识别为中枢的替代方法。我们的框架预测，我们提出的中枢位置可能在认知的多个方面发挥有影响力的作用，相反，通过其他方法（包括DMN中的显著区域）识别出的中枢可能不会产生如此广泛的影响。在这里，我们采用神经心理学方法，通过研究30名患者的长期认知和行为结果来直接检验这些预测，其中19名患者的病灶位于我们通过方法（高系统密度和参与系数）识别出的六个“目标”中枢，11名患者的病灶位于两个“对照”中枢（高中心度）。为支持我们的预测，我们发现，目标位置受损会产生严重且广泛的认知缺陷，而对照位置受损会产生更局限的缺陷。这些发现支持了我们对神经成像衍生的网络测量与认知之间关系的解释，并强化了基于经典神经解剖学对局灶性脑损伤后认知和行为结果的预测。
