Beyond causing local ischemia and cell damage at the site of injury, stroke strongly affects long-range anatomical connections, perturbing the functional organization of brain networks. Several studies reported functional connectivity abnormalities parallelling both behavioral deficits and functional recovery across different cognitive domains. FC alterations suggest that long-range communication in the brain is altered after stroke. However, standard FC analyses cannot reveal the directionality and time scale of inter-areal information transfer. We used resting-state fMRI and covariance-based Granger causality analysis to quantify network-level information transfer and its alteration in stroke. Two main large-scale anomalies were observed in stroke patients. First, inter-hemispheric information transfer was significantly decreased with respect to healthy controls. Second, stroke caused inter-hemispheric asymmetries, as information transfer within the affected hemisphere and from the affected to the intact hemisphere was significantly reduced. Both anomalies were more prominent in resting-state networks related to attention and language, and they correlated with impaired performance in several behavioral domains. Overall, our findings support the hypothesis that stroke provokes asymmetries between the affected and spared hemisphere, with different functional consequences depending on which hemisphere is lesioned.

除了在损伤部位引起局部缺血和细胞损伤外，中风还强烈影响远程解剖连接，扰乱大脑网络的功能组织。几项研究报告了功能连接异常，与不同认知领域的行为缺陷和功能恢复平行。FC 改变表明中风后大脑中的远程通信发生了改变。然而，标准的 FC 分析无法揭示区域间信息传递的方向性和时间尺度。我们使用静息状态 fMRI 和基于协方差的 Granger 因果分析来量化网络级信息传递及其在中风中的变化。在中风患者中观察到两个主要的大规模异常。第一的，与健康对照相比，半球间的信息传递显着减少。其次，中风导致半球间不对称，因为受影响半球内以及从受影响半球到完整半球的信息传输显着减少。这两种异常在与注意力和语言相关的静息状态网络中更为突出，并且与多个行为领域的表现受损相关。总体而言，我们的研究结果支持这样的假设，即中风会导致受影响的半球和幸存的半球之间出现不对称，并根据受损的半球产生不同的功能后果。这两种异常在与注意力和语言相关的静息状态网络中更为突出，并且与多个行为领域的表现受损相关。总体而言，我们的研究结果支持这样的假设，即中风会导致受影响的半球和幸存的半球之间出现不对称，并根据受损的半球产生不同的功能后果。这两种异常在与注意力和语言相关的静息状态网络中更为突出，并且与多个行为领域的表现受损相关。总体而言，我们的研究结果支持这样的假设，即中风会导致受影响的半球和幸存的半球之间出现不对称，并根据受损的半球产生不同的功能后果。