Key Laboratory of Cognition and Personality, Faculty of Psychology, Southwest University, Chongqing, 400715, China; Department of Data Analysis, University of Ghent, B9000, Ghent, Belgium.
Coma Science Group, GIGA Research Center, University of Liège, B4000, Liège, Belgium; Center for Clinical Brain Sciences, Centre for Dementia Prevention, UK Dementia Research Institute, University of Edinburgh, EH16 4SB, Edinburgh, United Kingdom.
Neuroimage. 2019 Oct 15;200:450-459. doi: 10.1016/j.neuroimage.2019.07.011. Epub 2019 Jul 5.
Functional imaging research has already contributed with several results to the study of neural correlates of consciousness. Apart from task-related activation derived in fMRI, PET based glucose metabolism rate or cerebral blood flow account for a considerable proportion of the study of brain activity under different levels of consciousness. Resting state functional connectivity MRI is playing a crucial role to explore the consciousness related functional integration, successfully complementing PET, another widely used neuroimaging technique. Here, spontaneous hemodynamic response is introduced to characterize resting state brain activity giving information on the local metabolism (neurovascular coupling), and useful to improve the time-resolved activity and connectivity measures based on BOLD fMRI. This voxel-wise measure is then used to investigate the loss of consciousness under Propofol anesthesia and unresponsive wakefulness syndrome. Changes in the hemodynamic response in precuneus and posterior cingulate are found to be a common principle underlying loss of consciousness in both conditions. The thalamus appears to be less obviously modulated by Propofol, compared with frontoparietal regions. However, a significant increase in spontaneous thalamic hemodynamic response was found in patients in unresponsive wakefulness syndrome compared with healthy controls. Our results ultimately show that anesthesia- or pathology-induced neurovascular coupling could be tracked by modulated spontaneous hemodynamic response derived from resting state fMRI.
功能成像研究已经为意识的神经相关研究做出了许多贡献。除了 fMRI 中得出的与任务相关的激活外，基于 PET 的葡萄糖代谢率或脑血流在不同意识水平下的大脑活动研究中占有相当大的比例。静息态功能连接 MRI 在探索与意识相关的功能整合方面发挥着关键作用，成功地补充了另一种广泛使用的神经影像学技术 PET。在这里，自发的血液动力学反应被引入来描述静息态大脑活动，提供关于局部代谢（神经血管耦联）的信息，有助于改善基于 BOLD fMRI 的时间分辨活动和连接性测量。然后，使用这种体素方法来研究异丙酚麻醉和无反应性觉醒综合征下的意识丧失。在前扣带回和后扣带回的血液动力学反应变化被发现是两种情况下意识丧失的共同原则。与额顶叶区域相比，丘脑似乎受异丙酚的调节不那么明显。然而，与健康对照组相比，无反应性觉醒综合征患者的自发丘脑血液动力学反应显著增加。我们的研究结果最终表明，麻醉或病理诱导的神经血管耦联可以通过静息状态 fMRI 得出的调制自发血液动力学反应来追踪。
