Hellyer Peter J, Scott Gregory, Shanahan Murray, Sharp David J, Leech Robert
Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, United Kingdom, Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE5 8AF, United Kingdom, and.
Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, United Kingdom.
J Neurosci. 2015 Jun 17;35(24):9050-63. doi: 10.1523/JNEUROSCI.4648-14.2015.
Current theory proposes that healthy neural dynamics operate in a metastable regime, where brain regions interact to simultaneously maximize integration and segregation. Metastability may confer important behavioral properties, such as cognitive flexibility. It is increasingly recognized that neural dynamics are constrained by the underlying structural connections between brain regions. An important challenge is, therefore, to relate structural connectivity, neural dynamics, and behavior. Traumatic brain injury (TBI) is a pre-eminent structural disconnection disorder whereby traumatic axonal injury damages large-scale connectivity, producing characteristic cognitive impairments, including slowed information processing speed and reduced cognitive flexibility, that may be a result of disrupted metastable dynamics. Therefore, TBI provides an experimental and theoretical model to examine how metastable dynamics relate to structural connectivity and cognition. Here, we use complementary empirical and computational approaches to investigate how metastability arises from the healthy structural connectome and relates to cognitive performance. We found reduced metastability in large-scale neural dynamics after TBI, measured with resting-state functional MRI. This reduction in metastability was associated with damage to the connectome, measured using diffusion MRI. Furthermore, decreased metastability was associated with reduced cognitive flexibility and information processing. A computational model, defined by empirically derived connectivity data, demonstrates how behaviorally relevant changes in neural dynamics result from structural disconnection. Our findings suggest how metastable dynamics are important for normal brain function and contingent on the structure of the human connectome.
当前理论认为，健康的神经动力学在一种亚稳态下运行，即大脑区域相互作用，以同时实现整合和分离的最大化。亚稳态可能赋予重要的行为特性，如认知灵活性。人们越来越认识到，神经动力学受到大脑区域之间潜在结构连接的限制。因此，一个重要的挑战是将结构连接性、神经动力学和行为联系起来。创伤性脑损伤（TBI）是一种典型的结构性连接障碍，创伤性轴突损伤会破坏大规模连接性，产生特征性的认知障碍，包括信息处理速度减慢和认知灵活性降低，这可能是亚稳态动力学破坏的结果。因此，TBI提供了一个实验和理论模型，以研究亚稳态动力学如何与结构连接性和认知相关。在这里，我们使用互补的实证和计算方法来研究亚稳态如何从健康的结构连接组中产生并与认知表现相关。我们发现，用静息态功能磁共振成像测量，TBI后大规模神经动力学中的亚稳态降低。这种亚稳态的降低与用扩散磁共振成像测量的连接组损伤有关。此外，亚稳态降低与认知灵活性和信息处理能力下降有关。一个由经验推导的连接性数据定义的计算模型，展示了神经动力学中与行为相关的变化是如何由结构断开引起的。我们的研究结果表明亚稳态动力学对正常脑功能很重要，并且取决于人类连接组的结构。
