同时进行的脑电图和功能磁共振成像表明，与麻醉诱导的无意识相关，皮质顶叶自上而下的处理受到损害。
Simultaneous electroencephalographic and functional magnetic resonance imaging indicate impaired cortical top-down processing in association with anesthetic-induced unconsciousness.
机构信息
* Research Fellow, ‖ Resident, # Research Assistant, *** Professor, Director Chair, Department of Anesthesiology, † Associate Professor, § Resident, †† Research Fellow, ## Professor, Director Chair, Department of Neurology, ‡ Research Fellow, ‖‖ Professor, Director Chair, Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. ‡‡ Research Fellow, Department of Medical Statistics and Epidemiology, Technische Universität München, Munich, Germany. §§ Research Fellow, Max Planck Institute of Psychiatry, Munich, Germany. ** Resident, ††† Professor, Director Chair, Department of Anesthesiology, Klinikum rechts der Isar, Technische Universität München, and Department of Anesthesiology, Witten/Herdecke University, Helios Clinic Wuppertal, Wuppertal, Germany.
出版信息
Anesthesiology. 2013 Nov;119(5):1031-42. doi: 10.1097/ALN.0b013e3182a7ca92.
BACKGROUND
In imaging functional connectivity (FC) analyses of the resting brain, alterations of FC during unconsciousness have been reported. These results are in accordance with recent electroencephalographic studies observing impaired top-down processing during anesthesia. In this study, simultaneous records of functional magnetic resonance imaging (fMRI) and electroencephalogram were performed to investigate the causality of neural mechanisms during propofol-induced loss of consciousness by correlating FC in fMRI and directional connectivity (DC) in electroencephalogram.
METHODS
Resting-state 63-channel electroencephalogram and blood oxygen level-dependent 3-Tesla fMRI of 15 healthy subjects were simultaneously registered during consciousness and propofol-induced loss of consciousness. To indicate DC, electroencephalographic symbolic transfer entropy was applied as a nonlinear measure of mutual interdependencies between underlying physiological processes. The relationship between FC of resting-state networks of the brain (z values) and DC was analyzed by a partial correlation.
RESULTS
Independent component analyses of resting-state fMRI showed decreased FC in frontoparietal default networks during unconsciousness, whereas FC in primary sensory networks increased. DC indicated a decline in frontal-parietal (area under the receiver characteristic curve, 0.92; 95% CI, 0.68-1.00) and frontooccipital (0.82; 0.53-1.00) feedback DC (P<0.05 corrected). The changes of FC in the anterior default network correlated with the changes of DC in frontal-parietal (rpartial=+0.62; P=0.030) and frontal-occipital (+0.63; 0.048) electroencephalographic electrodes (P<0.05 corrected).
CONCLUSION
The simultaneous propofol-induced suppression of frontal feedback connectivity in the electroencephalogram and of frontoparietal FC in the fMRI indicates a fundamental role of top-down processing for consciousness.
背景
在对静息态大脑的功能连接（FC）进行的影像学研究中，报道了无意识状态下 FC 的改变。这些结果与最近的脑电图研究结果一致，这些研究结果表明麻醉期间存在自上而下加工受损的情况。在这项研究中，通过将 fMRI 中的 FC 与脑电图中的定向连接（DC）相关联，同时记录了功能磁共振成像（fMRI）和脑电图的记录，以研究丙泊酚诱导意识丧失期间神经机制的因果关系，从而研究丙泊酚诱导意识丧失期间神经机制的因果关系。
方法
在意识和丙泊酚诱导的意识丧失期间，同时对 15 名健康受试者进行了 63 通道脑电图和血氧水平依赖 3T fMRI 的静息状态记录。为了表示 DC，应用了脑电图符号传递熵作为潜在生理过程之间相互依存关系的非线性度量。通过偏相关分析了大脑静息态网络的 FC（z 值）与 DC 之间的关系。
结果
静息态 fMRI 的独立成分分析显示，无意识状态下额顶默认网络的 FC 降低，而初级感觉网络的 FC 增加。DC 表明额顶（接受者特征曲线下面积，0.92；95%CI，0.68-1.00）和额枕（0.82；0.53-1.00）反馈 DC 下降（P<0.05 校正）。前默认网络的 FC 变化与额顶（rpartial=+0.62；P=0.030）和额枕（rpartial=+0.63；0.048）脑电图电极的 DC 变化相关（P<0.05 校正）。
结论
同时抑制脑电图中的额反馈连接和 fMRI 中的额顶 FC 表明，自上而下的处理对意识起着根本性的作用。
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