Jagannathan Sridhar R, Jeans Rhiannon, Van De Poll Matthew N, van Swinderen Bruno
Department of Psychology, University of Cambridge, Cambridge, United Kingdom.
Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
bioRxiv. 2023 Jun 13:2023.06.12.544704. doi: 10.1101/2023.06.12.544704.
Sleep is observed in most animals, which suggests it subserves a fundamental process associated with adaptive biological functions. However, the evidence to directly associate sleep with a specific function is lacking, in part because sleep is not a single process in many animals. In humans and other mammals, different sleep stages have traditionally been identified using electroencephalograms (EEGs), but such an approach is not feasible in different animals such as insects. Here, we perform long-term multichannel local field potential (LFP) recordings in the brains of behaving flies undergoing spontaneous sleep bouts. We developed protocols to allow for consistent spatial recordings of LFPs across multiple flies, allowing us to compare the LFP activity across awake and sleep periods and further compare the same to induced sleep. Using machine learning, we uncover the existence of distinct temporal stages of sleep and explore the associated spatial and spectral features across the fly brain. Further, we analyze the electrophysiological correlates of micro-behaviours associated with certain sleep stages. We confirm the existence of a distinct sleep stage associated with rhythmic proboscis extensions and show that spectral features of this sleep-related behavior differ significantly from those associated with the same behavior during wakefulness, indicating a dissociation between behavior and the brain states wherein these behaviors reside.
大多数动物都有睡眠现象，这表明睡眠有助于一个与适应性生物学功能相关的基本过程。然而，缺乏将睡眠与特定功能直接联系起来的证据，部分原因是在许多动物中睡眠并非单一过程。在人类和其他哺乳动物中，传统上使用脑电图（EEG）来识别不同的睡眠阶段，但这种方法在昆虫等不同动物中并不可行。在这里，我们对处于自发睡眠周期的行为果蝇大脑进行了长期多通道局部场电位（LFP）记录。我们开发了协议，以实现对多只果蝇LFP的一致空间记录，使我们能够比较清醒期和睡眠期的LFP活动，并进一步将其与诱导睡眠进行比较。通过机器学习，我们发现了睡眠中不同时间阶段的存在，并探索了果蝇大脑中相关的空间和频谱特征。此外，我们分析了与某些睡眠阶段相关的微行为的电生理相关性。我们证实了与有节奏的喙伸展相关的独特睡眠阶段的存在，并表明这种与睡眠相关行为的频谱特征与清醒时相同行为的频谱特征有显著差异，这表明行为与这些行为所处的大脑状态之间存在分离。
