Background: Inhalational anesthetic-induced burst suppression (BS) is classically considered a bilaterally synchronous rhythm. However, local asynchrony has been predicted in theoretical studies and reported in patients with pre-existing focal pathology. Method: We used high-speed widefield calcium imaging to study the spatiotemporal dynamics of isoflurane-induced BS in rats. Results: We found that isoflurane-induced BS is not a globally synchronous rhythm. In the neocortex, neural activity first emerged in a spatially shifting, variably localized focus. Subsequent propagation across the whole cortex was rapid, typically within <100 milliseconds, giving the superficial resemblance to global synchrony. Neural activity remained locally asynchronous during the bursts, forming complex recurrent propagating waves. Despite propagation variability, spatial sequences of burst propagation were largely preserved between the hemispheres, and neural activity was highly correlated between the homotopic areas. The critical role of the thalamus in cortical burst initiation was demonstrated by using unilateral thalamic tetrodotoxin injection. Conclusion: The classical impression that anesthetics-induced BS is a state of global brain synchrony is inaccurate. Bursts are a series of shifting local cortical events facilitated by thalamic projection that unfold as rapid, bilaterally asynchronous propagating waves.

中文翻译：

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异氟醚诱导的爆发抑制是一种丘脑调节的、局灶性节律，在大鼠中具有持续的局部异步和可变传播模式

背景：吸入麻醉剂诱发的爆发抑制 (BS) 通常被认为是双侧同步节律。然而，在理论研究中已经预测到局部不同步，并且在具有预先存在的局灶性病理的患者中进行了报道。方法：我们使用高速宽场钙成像来研究异氟醚诱导的大鼠 BS 的时空动态。结果：我们发现异氟醚诱导的 BS 不是全局同步的节律。在新皮层中，神经活动首先出现在空间移动、局部变化的焦点中。随后在整个皮层中的传播很快，通常在 <100 毫秒内，表面上与全球同步相似。神经活动在爆发期间保持局部异步，形成复杂的循环传播波。尽管传播变异，爆发传播的空间序列在半球之间大部分保留，并且神经活动在同位区域之间高度相关。通过使用单侧丘脑河豚毒素注射证明了丘脑在皮质爆发启动中的关键作用。结论：关于麻醉剂引起的 BS 是一种全球大脑同步状态的经典印象是不准确的。爆发是由丘脑投射促进的一系列移动的局部皮质事件，这些事件以快速、双边异步传播的波的形式展开。结论：关于麻醉剂引起的 BS 是一种全球大脑同步状态的经典印象是不准确的。爆发是由丘脑投射促进的一系列移动的局部皮质事件，这些事件以快速、双边异步传播的波的形式展开。结论：关于麻醉剂引起的 BS 是一种全球大脑同步状态的经典印象是不准确的。爆发是由丘脑投射促进的一系列移动的局部皮质事件，这些事件以快速、双边异步传播的波的形式展开。