Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA.
Curr Biol. 2023 Sep 11;33(17):3660-3668.e4. doi: 10.1016/j.cub.2023.07.043. Epub 2023 Aug 7.
The needs fulfilled by sleep are unknown, though the effects of insufficient sleep are manifold. To better understand how the need to sleep is sensed and discharged, much effort has gone into identifying the neural circuits involved in regulating arousal, especially those that promote sleep. In prevailing models, the dorsal fan-shaped body (dFB) plays a central role in this process in the fly brain. In the present study we manipulated various properties of the dFB including its electrical activity, synaptic output, and endogenous gene expression. In each of these experimental contexts we were unable to identify any effect on sleep that could be unambiguously mapped to the dFB. Furthermore, we found evidence that sleep phenotypes previously attributed to the dFB were caused by genetic manipulations that inadvertently targeted the ventral nerve cord. We also examined expression of two genes whose purported effects have been attributed to functions within a specific subpopulation of dFB neurons. In both cases we found little to no expression in the expected cells. Collectively, our results cast doubt on the prevailing hypothesis that the dFB plays a central role in promoting sleep.
睡眠满足的需求尚不清楚，尽管睡眠不足的影响是多方面的。为了更好地理解睡眠需求是如何被感知和释放的，人们付出了很大的努力来识别参与调节觉醒的神经回路，特别是那些促进睡眠的神经回路。在流行的模型中，背部扇形体（dFB）在果蝇大脑中调节觉醒的过程中起着核心作用。在本研究中，我们操纵了 dFB 的各种特性，包括其电活动、突触输出和内源性基因表达。在这些实验环境中，我们都无法确定任何可以明确映射到 dFB 的睡眠效应。此外，我们发现先前归因于 dFB 的睡眠表型是由遗传操作引起的，这些遗传操作无意中针对了腹神经索。我们还检查了两个基因的表达，它们的假定作用归因于 dFB 神经元特定亚群内的功能。在这两种情况下，我们发现在预期的细胞中几乎没有表达。总的来说，我们的结果对 dFB 发挥核心作用促进睡眠的流行假设提出了质疑。
