Weakly Correlated Local Cortical State Switches under Anesthesia Lead to Strongly Correlated Global States.
Weakly Correlated Local Cortical State Switches under Anesthesia Lead to Strongly Correlated Global States.
复制标题
DOI：
10.1523/jneurosci.0123-22.2022
复制
发表时间：
2022-11-30
影响因子：
5.3
通讯作者：
Proekt, Alex
中科院分区：
文献类型：
--
作者：
Blackwood, Ethan B;Shortal, Brenna P;Proekt, Alex
在从麻醉中恢复的过程中，大脑活动会在一小组离散状态之间突然切换。令人惊讶的是，这种转换在恒定剂量的麻醉下也会发生，即使在没有刺激的情况下也是如此。这些亚稳态和它们之间的转换被认为形成了最终引导大脑回到清醒状态的“脚手架”。将皮质活动模式限制在这些状态并控制不同皮质区域之间的状态如何协调的过程尚不清楚。如果状态转换是由皮质下调制驱动的，不同的皮质部位应该表现出近同步的状态转换。相反，时空异质性表明状态转换是通过皮质相互作用来协调的。为了区分这些假说，我们量化了暴露在固定异氟醚浓度下的雄性大鼠大脑状态的同步性。状态是通过视觉和运动皮质各层记录的局部场电位的频谱来定义的。转换同步度量表明，大多数状态转换都是高度局部化的。此外，虽然大多数大脑皮层部位显示出统计上显著的状态和状态转换时间的耦合，但耦合强度通常较弱。丘脑输入层(L4)中的状态和状态转换与颗粒上层和颗粒下层中的状态和状态转换尤其分离。这表明，状态转换不是通过广泛投射的调制系统强加给大脑皮层的。尽管每个成对相互作用通常都是弱的，但我们证明了这种弱相互作用的数量足以将全局活动限制在少数离散状态。意义陈述麻醉后大脑持续恢复到清醒状态，但人们对这一过程知之甚少。以前的工作表明，在麻醉恢复期间，皮质丘脑活动进入几个离散模式之一。将大脑皮层限制在几个离散状态的神经机制仍不清楚。全球状态可以通过皮质下核团的波动来协调，这些核团广泛投射到大脑皮层。或者，这些状态可能来自大脑皮层本身的相互作用。在这里，我们通过证明大多数皮质部位对表现出弱耦合来为后一种可能性提供证据。因此，我们为进一步研究皮质活动状态耦合的特定细胞和网络机制奠定了基础。
During recovery from anesthesia, brain activity switches abruptly between a small set of discrete states. Surprisingly, this switching also occurs under constant doses of anesthesia, even in the absence of stimuli. These metastable states and the transitions between them are thought to form a “scaffold” that ultimately guides the brain back to wakefulness. The processes that constrain cortical activity patterns to these states and govern how states are coordinated between different cortical regions are unknown. If state transitions were driven by subcortical modulation, different cortical sites should exhibit near-synchronous state transitions. Conversely, spatiotemporal heterogeneity would suggest that state transitions are coordinated through corticocortical interactions. To differentiate between these hypotheses, we quantified synchrony of brain states in male rats exposed to a fixed isoflurane concentration. States were defined from spectra of local field potentials recorded across layers of visual and motor cortices. A transition synchrony measure shows that most state transitions are highly localized. Furthermore, while most pairs of cortical sites exhibit statistically significant coupling of both states and state transition times, coupling strength is typically weak. States and state transitions in the thalamic input layer (L4) are particularly decoupled from those in supragranular and infragranular layers. This suggests that state transitions are not imposed on the cortex by broadly projecting modulatory systems. Although each pairwise interaction is typically weak, we show that the multitude of such weak interactions is sufficient to confine global activity to a small number of discrete states. SIGNIFICANCE STATEMENT The brain consistently recovers to wakefulness after anesthesia, but this process is poorly understood. Previous work revealed that, during recovery from anesthesia, corticothalamic activity falls into one of several discrete patterns. The neuronal mechanisms constraining the cortex to just a few discrete states remain unknown. Global states could be coordinated by fluctuations in subcortical nuclei that project broadly to the cortex. Alternatively, these states may emerge from interactions within the cortex itself. Here, we provide evidence for the latter possibility by demonstrating that most pairs of cortical sites exhibit weak coupling. We thereby lay groundwork for future investigations of the specific cellular and network mechanisms of corticocortical activity state coupling.