Department of Psychology, Sapienza University of Rome, Rome 00185, Italy,
Fondazione Santa Lucia, Istituto Di Ricovero e Cura a Carattere Scientifico, Rome 00142, Italy.
J Neurosci. 2018 Apr 11;38(15):3858-3871. doi: 10.1523/JNEUROSCI.1089-17.2018. Epub 2018 Mar 19.
Networks hubs represent points of convergence for the integration of information across many different nodes and systems. Although a great deal is known on the topology of hub regions in the human brain, little is known about their temporal dynamics. Here, we examine the static and dynamic centrality of hub regions when measured in the absence of a task (rest) or during the observation of natural or synthetic visual stimuli. We used Magnetoencephalography (MEG) in humans (both sexes) to measure static and transient regional and network-level interaction in α- and β-band limited power (BLP) in three conditions: visual fixation (rest), viewing of movie clips (natural vision), and time-scrambled versions of the same clips (scrambled vision). Compared with rest, we observed in both movie conditions a robust decrement of α-BLP connectivity. Moreover, both movie conditions caused a significant reorganization of connections in the α band, especially between networks. In contrast, β-BLP connectivity was remarkably similar between rest and natural vision. Not only the topology did not change, but the joint dynamics of hubs in a core network during natural vision was predicted by similar fluctuations in the resting state. We interpret these findings by suggesting that slow-varying fluctuations of integration occurring in higher-order regions in the β band may be a mechanism to anticipate and predict slow-varying temporal patterns of the visual environment. A fundamental question in neuroscience concerns the function of spontaneous brain connectivity. Here, we tested the hypothesis that topology of intrinsic brain connectivity and its dynamics might predict those observed during natural vision. Using MEG, we tracked the static and time-varying brain functional connectivity when observers were either fixating or watching different movie clips. The spatial distribution of connections and the dynamics of centrality of a set of regions were similar during rest and movie in the β band, but not in the α band. These results support the hypothesis that the intrinsic β-rhythm integration occurs with a similar temporal structure during natural vision, possibly providing advanced information about incoming stimuli.
网络枢纽代表了来自许多不同节点和系统的信息整合的汇聚点。尽管人们对人类大脑中枢纽区域的拓扑结构有了很多了解,但对其时间动态却知之甚少。在这里,我们研究了在没有任务(休息)或观察自然或合成视觉刺激时,枢纽区域的静态和动态中心性。我们使用脑磁图(MEG)在人类(两性)中测量了在三种条件下的α-和β-波段受限功率(BLP)的静态和瞬态区域和网络级交互:视觉固定(休息)、观看电影片段(自然视觉)和相同片段的时间混淆版本(混淆视觉)。与休息相比,我们在电影条件下观察到α-BLP 连通性的显著降低。此外,两种电影条件都会导致 α 频段的连接发生重大重组,尤其是在网络之间。相比之下,β-BLP 连接性在休息和自然视觉之间非常相似。不仅拓扑结构没有改变,而且在自然视觉期间核心网络中枢纽的联合动力学可以通过休息状态下相似的波动来预测。我们通过提出以下假设来解释这些发现,即在β带中发生的高阶区域中缓慢变化的整合波动可能是一种预测视觉环境中缓慢变化的时间模式的机制。神经科学中的一个基本问题是自发脑连接的功能。在这里,我们测试了这样一个假设,即内在脑连接的拓扑结构及其动态可能会预测在自然视觉期间观察到的连接。使用 MEG,我们跟踪了观察者在注视或观看不同电影片段时的静态和时变脑功能连接。在β带中,连接的空间分布和一组区域的中心性动态在休息和电影期间相似,但在α带中则不同。这些结果支持这样的假设,即内在β-节律整合在自然视觉期间以相似的时间结构发生,可能提供有关传入刺激的高级信息。