Guo Yu, Cao Bolin, He Yanbin, Xie Qiuyou, Liang Qimei, Lan Yue, Zhang Mingxian, Qiu Yidan, Yu Ronghao, Huang Ruiwang
School of Psychology, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, Ministry of Education Key Laboratory of Brain Cognition and Educational Science, South China Normal University, Guangzhou, Guangdong, 510631, China.
Traumatic Brain Injury Rehabilitation Department & Severe Rehabilitation Department, Guangdong Province Work Injury Rehabilitation Hospital, Guangzhou, Guangdong, 510440, China.
Brain Commun. 2023 Mar 28;5(2):fcad069. doi: 10.1093/braincomms/fcad069. eCollection 2023.
Disorders of consciousness are impaired states of consciousness caused by severe brain injuries. Previous resting-state functional magnetic resonance imaging studies have reported abnormal brain network properties at different topological scales in patients with disorders of consciousness by using graph theoretical analysis. However, it is still unclear how inter-regional directed propagation activities affect the topological organization of functional brain networks in patients with disorders of consciousness. To reveal the altered topological organization in patients with disorders of consciousness, we constructed whole-brain directed functional networks by combining functional connectivity analysis and time delay estimation. Then we performed graph theoretical analysis based on the directed functional brain networks at three topological scales, from the nodal scale, the resting-state network scale to the global scale. Finally, the canonical correlation analysis was used to determine the correlations between altered topological properties and clinical scores in patients with disorders of consciousness. At the nodal scale, we observed decreased in-degree and increased out-degree in the precuneus in patients with disorders of consciousness. At the resting-state network scale, the patients with disorders of consciousness showed reorganized motif patterns within the default mode network and between the default mode network and other resting-state networks. At the global scale, we found a lower global clustering coefficient in the patients with disorders of consciousness than in the controls. The results of the canonical correlation analysis showed that the abnormal degree and the disrupted motif were significantly correlated with the clinical scores of the patients with disorders of consciousness. Our findings showed that consciousness impairment can be revealed by abnormal directed connection patterns at multiple topological scales in the whole brain, and the disrupted directed connection patterns may serve as clinical biomarkers to assess the dysfunction of patients with disorders of consciousness.
意识障碍是由严重脑损伤引起的意识受损状态。以往的静息态功能磁共振成像研究通过图论分析报告了意识障碍患者在不同拓扑尺度下脑网络属性异常。然而，尚不清楚区域间的定向传播活动如何影响意识障碍患者功能性脑网络的拓扑组织。为揭示意识障碍患者拓扑组织的改变，我们结合功能连接分析和时间延迟估计构建了全脑定向功能网络。然后我们基于定向功能性脑网络在三个拓扑尺度（从节点尺度、静息态网络尺度到全局尺度）进行了图论分析。最后，采用典型相关分析确定意识障碍患者拓扑属性改变与临床评分之间的相关性。在节点尺度上，我们观察到意识障碍患者楔前叶的入度降低而出度增加。在静息态网络尺度上，意识障碍患者在默认模式网络内以及默认模式网络与其他静息态网络之间表现出重新组织的基序模式。在全局尺度上，我们发现意识障碍患者的全局聚类系数低于对照组。典型相关分析结果表明，异常程度和破坏的基序与意识障碍患者的临床评分显著相关。我们的研究结果表明，意识障碍可通过全脑多个拓扑尺度下异常的定向连接模式揭示，而破坏的定向连接模式可能作为评估意识障碍患者功能障碍的临床生物标志物。
