Circadian clocks are biochemical time-keeping machines that synchronize animal behavior and physiology with planetary rhythms. In Drosophila, the core components of the clock comprise a transcription/translation feedback loop and are expressed in seven neuronal clusters in the brain. Although it is increasingly evident that the clocks in each of the neuronal clusters are regulated differently, how these clocks communicate with each other across the circadian neuronal network is less clear. Here, we review the latest evidence that describes the physical connectivity of the circadian neuronal network . Using small ventral lateral neurons as a starting point, we summarize how one clock may communicate with another, highlighting the signaling pathways that are both upstream and downstream of these clocks. We propose that additional efforts are required to understand how temporal information generated in each circadian neuron is integrated across a neuronal circuit to regulate rhythmic behavior.

昼夜节律钟是生物化学计时机器，使动物行为和生理与行星节律同步。在果蝇中，时钟的核心组件包括转录/翻译反馈环，并在大脑中的七个神经元簇中表达。尽管越来越明显的是，每个神经元簇中的时钟受到不同的调节，但这些时钟如何通过昼夜节律神经元网络相互通信还不太清楚。在这里，我们回顾了描述昼夜节律神经元网络物理连接的最新证据。使用小的腹侧外侧神经元作为起点，我们总结了一个时钟如何与另一个时钟通信，突出显示这些时钟上游和下游的信号通路。我们建议需要付出额外的努力来理解每个昼夜节律神经元生成的时间信息如何跨神经元回路整合以调节节律行为。