Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, 311121, People's Republic of China.
Institutes of Psychological Sciences, Hangzhou Normal University, Hangzhou, 311121, People's Republic of China.
Hum Brain Mapp. 2018 May;39(5):2035-2046. doi: 10.1002/hbm.23984. Epub 2018 Jan 28.
Which temporal features that can characterize different brain states (i.e., consciousness or unconsciousness) is a fundamental question in the neuroscience of consciousness. Using resting-state functional magnetic resonance imaging (rs-fMRI), we investigated the spatial patterns of two temporal features: the long-range temporal correlations (LRTCs), measured by power-law exponent (PLE), and temporal variability, measured by standard deviation (SD) during wakefulness and anesthetic-induced unconsciousness. We found that both PLE and SD showed global reductions across the whole brain during anesthetic state comparing to wakefulness. Importantly, the relationship between PLE and SD was altered in anesthetic state, in terms of a spatial "decoupling." This decoupling was mainly driven by a spatial pattern alteration of the PLE, rather than the SD, in the anesthetic state. Our results suggest differential physiological grounds of PLE and SD and highlight the functional importance of the topographical organization of LRTCs in maintaining an optimal spatiotemporal configuration of the neural dynamics during normal level of consciousness. The central role of the spatial distribution of LRTCs, reflecting temporo-spatial nestedness, may support the recently introduced temporo-spatial theory of consciousness (TTC).
哪些时间特征可以表征不同的大脑状态（即意识或无意识），是意识神经科学中的一个基本问题。本研究使用静息态功能磁共振成像（rs-fMRI），在清醒和麻醉诱导无意识状态下，研究了两个时间特征的空间模式：长程时间相关性（LRTCs），由幂律指数（PLE）测量；以及时间变异性，由标准差（SD）测量。结果发现，与清醒状态相比，麻醉状态下整个大脑的 PLE 和 SD 均表现出全局降低。重要的是，PLE 和 SD 之间的关系在麻醉状态下发生了改变，表现为空间“解耦”。这种解耦主要是由麻醉状态下 PLE 的空间模式改变驱动的，而不是 SD。我们的结果表明 PLE 和 SD 的生理基础不同，并强调了 LRTCs 的拓扑组织在维持正常意识水平下神经动力学的最优时空配置方面的功能重要性。LRTCs 的空间分布反映了时间-空间嵌套性，可能支持最近提出的意识的时间-空间理论（TTC）。
