Venkatesan Umesh M, Dennis Nancy A, Hillary Frank G
1 Department of Psychology, The Pennsylvania State University , University Park, Pennsylvania.
J Neurotrauma. 2015 Feb 15;32(4):252-64. doi: 10.1089/neu.2013.3318. Epub 2014 Dec 10.
Whereas traumatic brain injury (TBI) results in widespread disruption of neural networks, changes in regional resting-state functional connectivity patterns after insult remain unclear. Specifically, little is known about the chronology of emergent connectivity alterations and whether they persist after a critical recovery window. We used resting-state functional magnetic resonance imaging and seed-voxel correlational analyses in both cross-sectional and longitudinal designs to probe intrinsic connectivity patterns involving the posterior cingulate cortex (PCC) and hippocampi, regions shown to be important in the default mode network (DMN) and vulnerable to neuropathology. A total of 22 participants in the chronic stage of moderate-to-severe TBI and 18 healthy controls were included for cross-sectional study. Longitudinal analyses included 13 individuals in the TBI group for whom data approximately 3 months after injury (subacute) were available. Overall, results indicated dissociable connectivity trajectories of the PCC and hippocampi during recovery from TBI, with PCC alterations characterized by early hypersynchrony with the anterior DMN that is gradually reduced, and hippocampal changes marked by increasing synchrony with proximal cortex and subcortex. The PCC also showed increasing antiphase synchrony with posterior attentional regions, and the hippocampi showed decreasing antiphase synchrony with frontal attentional regions. Antiphase synchrony of the hippocampus and dorsolateral prefrontal cortex at the subacute stage of TBI was positively associated with attentional performance on neuropsychological tests at both the subacute and chronic stages. Our findings highlight the heterogeneity of regional whole-brain connectivity changes after TBI, and suggest that residual connectivity alterations exist in the clinically stable phase of TBI. Parallels between the chronicity of the observed effects and findings in neurodegenerative disease are discussed in the context of potential long-term outcomes of TBI.
创伤性脑损伤（TBI）会导致神经网络广泛破坏，但其损伤后区域静息态功能连接模式的变化仍不清楚。具体而言，对于新兴连接改变的时间顺序以及它们在关键恢复窗口后是否持续存在，人们知之甚少。我们在横断面和纵向设计中使用静息态功能磁共振成像和种子体素相关分析，以探究涉及后扣带回皮质（PCC）和海马体的内在连接模式，这些区域在默认模式网络（DMN）中很重要且易受神经病理学影响。横断面研究纳入了22名中重度TBI慢性期参与者和18名健康对照。纵向分析包括TBI组中的13名个体，他们在受伤后约3个月（亚急性期）有可用数据。总体而言，结果表明TBI恢复过程中PCC和海马体的连接轨迹不同，PCC改变的特征是早期与前DMN的超同步逐渐减少，海马体变化的特征是与近端皮质和皮质下的同步性增加。PCC还显示与后注意区域的反相同步增加，海马体显示与前注意区域的反相同步减少。TBI亚急性期海马体与背外侧前额叶皮质的反相同步与亚急性期和慢性期神经心理测试中的注意力表现呈正相关。我们的研究结果突出了TBI后区域全脑连接变化的异质性，并表明在TBI临床稳定期存在残留的连接改变。在讨论TBI潜在长期结果的背景下，探讨了观察到的效应的慢性与神经退行性疾病研究结果之间的相似之处。
