Isoflurane Impairs Low-Frequency Feedback but Leaves High-Frequency Feedforward Connectivity Intact in the Fly Brain.
Isoflurane Impairs Low-Frequency Feedback but Leaves High-Frequency Feedforward Connectivity Intact in the Fly Brain.
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DOI：
10.1523/eneuro.0329-17.2018
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发表时间：
2018-01
期刊：
影响因子：
3.4
通讯作者：
Tsuchiya N
中科院分区：
文献类型：
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作者：
Cohen D;van Swinderen B;Tsuchiya N
分层组织的大脑通过前馈（FF）和反馈（FB）路径进行通信。在哺乳动物中，FF 和 FB 由清醒期间较高和较低的频率介导。在多种哺乳动物中，全身麻醉剂会优先损害 FB。这表明 FB 在唤醒大脑方面发挥着关键作用。果蝇（果蝇）的大脑也是分层组织的，但这些大脑中是否存在 FB 尚未确定。在这里，我们通过同时记录低阶外围结构和高阶中央结构的局部场电位（LFP）来研究果蝇大脑中的 FB。我们使用格兰杰因果关系（GC）分析了数据，这是这种分析技术首次应用于昆虫大脑的记录。我们的分析表明，低频（0.1–5 Hz）介导从中心到外围的 FB，而较高频率（10–45 Hz）则在相反方向介导 FF。此外，异氟烷麻醉优先减少FB。我们的结果表明，FF 和 FB 的光谱特征可能是从昆虫到哺乳动物都保守的分层组织的大脑的特征。我们推测全身麻醉剂可能通过针对支持 FB 的机制而导致跨物种的反应迟钝。
Hierarchically organized brains communicate through feedforward (FF) and feedback (FB) pathways. In mammals, FF and FB are mediated by higher and lower frequencies during wakefulness. FB is preferentially impaired by general anesthetics in multiple mammalian species. This suggests FB serves critical functions in waking brains. The brain of Drosophila melanogaster (fruit fly) is also hierarchically organized, but the presence of FB in these brains is not established. Here, we studied FB in the fly brain, by simultaneously recording local field potentials (LFPs) from low-order peripheral structures and higher-order central structures. We analyzed the data using Granger causality (GC), the first application of this analysis technique to recordings from the insect brain. Our analysis revealed that low frequencies (0.1–5 Hz) mediated FB from the center to the periphery, while higher frequencies (10–45 Hz) mediated FF in the opposite direction. Further, isoflurane anesthesia preferentially reduced FB. Our results imply that the spectral characteristics of FF and FB may be a signature of hierarchically organized brains that is conserved from insects to mammals. We speculate that general anesthetics may induce unresponsiveness across species by targeting the mechanisms that support FB.