Do single neurons need to sleep and why? Investigating the cellular signatures o

单个神经元需要睡眠吗？为什么？

• 批准号: 9503796
• 负责人: Chiara Cirelli
• 金额: $ 37.98万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9503796
• 关键词: Address; Behavior; Brain; Calcium; Cell Count; Cells; Chemosensitization; Cognition; Complement; Complex; Cortical Column; Data; Drosophila genus; Electrodes; Electrophysiology (science); Environment; Exposure to; Fatigue; Human; Impairment; Individual; Lead; Learning; Mammals; Mediating; Methods; Monitor; Motor Cortex; Mus; Mushroom Bodies; Neuronal Plasticity; Neurons; Organism; Performance; Rattus; Rest; Rodent; Scalp structure; Sleep; Slow-Wave Sleep; Stimulus; Synapses; Synaptic plasticity; System; Testing; Time; Training; Tube; awake; environmental enrichment for laboratory animals; experimental study; fly; in vivo calcium imaging; mutant; neuronal circuitry; relating to nervous system; response; sensory stimulus; sleep regulation

ABSTRACT Sleep is thought to be essential to restore brain functions, and converging evidence suggests that a key function may be to rebalance cellular changes triggered by plasticity during wake. This evidence is consistent with the hypothesis that sleep and wake may occur, be regulated, and perform their functions at the level of individual neurons. Recently, using multi-array recordings in freely moving rats, we obtained direct evidence that sleep can occur locally within a group of cortical neurons, while the rest of the brain remains awake, and that such "local sleep" increases with the duration of wake. If so, many questions arise: does local sleep also occur in species very different from mammals, such as flies? Are the mechanisms underlying the occurrence of local sleep similar to those that are known to regulate sleep need, specifically intense neural plasticity leading to tiredness, which requires sleep to enforce synaptic renormalization? Or does local sleep reflect temporary neuronal fatigue due to intense neural activity and short-lasting depletion of energy or calcium stores, and thus not qualify properly as sleep? Finally, it is unknown whether there are cellular/ultrastructural signatures that sleep has occurred and presumably performed its functions. In this proposal, we will test whether local sleep exists in flies by using in vivo calcium imaging to monitor simultaneously the activity of dozens of neurons in specific neuronal circuits. We will then test whether local sleep, like sleep proper, is regulated by intense synaptic plasticity ("tiredness") or instead by mere activity ("fatigue"). To do so we will first establish if local sleep increases during extended wake in a complex enriched environment (fly mall), expected to lead to tiredness in the mushroom bodies, relative to extended wake in an impoverished environment (single tube). Next, we will induce local dTrpA1-mediated activation during extended wake in single tubes, as well as during sleep. These 2 conditions of intense activity with little plasticity are expected to lead to fatigue, and their effects on local sleep will again be compared with those of extended wake in single tubes. To further decouple the effects of plasticity from those of activity we will repeat the experiments in learning mutants, in which exposure to the fly mall should not lead to plasticity/tiredness. Finally, we will use SBF-SEM to test whether there are ultrastructural signatures that can distinguish neurons of flies that have been awake from those of flies that slept, and compare the effects of wake with plasticity leading to tiredness with those of wake associated with dTrpA1-mediated intense firing leading to fatigue. Altogether, these studies in flies will complement those in mice in Project II, which use similar or the very same methods. Together, they will establish if sleep and wake are regulated homeostatically at the single neuron level, and if they leave ultrastructural signatures that reflect their consequences and functions for individual cells.

摘要 睡眠被认为对恢复大脑功能至关重要，越来越多的证据表明， 其功能可能是在清醒期间重新平衡由可塑性触发的细胞变化。这些证据与 假设睡眠和觉醒可能发生，被调节，并在睡眠水平上执行其功能。 单个神经元。最近，在自由活动的大鼠中使用多阵列记录，我们获得了直接证据， 睡眠可以发生在一组皮质神经元中，而大脑的其他部分仍然清醒， 这种“局部睡眠”随着清醒的持续时间而增加。如果是这样，许多问题就出现了： 发生在与哺乳动物非常不同的物种中，比如苍蝇？是否是导致 局部睡眠类似于那些已知的调节睡眠需要，特别是强烈的神经可塑性导致 疲劳，这需要睡眠来加强突触重整？还是局部睡眠反映了 由于强烈的神经活动和能量或钙储存的短暂消耗而引起的神经元疲劳， 不算睡觉吗最后，尚不清楚是否存在细胞/超微结构特征， 睡眠已经发生，并可能执行其功能。在这个建议中，我们将测试本地睡眠是否 存在于苍蝇中，通过使用体内钙成像同时监测几十个神经元的活动， 特定的神经回路然后，我们将测试局部睡眠是否像正常睡眠一样， 突触可塑性（“疲劳”）或仅仅是活动（“疲劳”）。要做到这一点，我们将首先确定，如果当地 在复杂的丰富环境（飞行商场）中，睡眠在长时间清醒期间增加，预计会导致 在蘑菇体疲劳，相对于延长唤醒在一个贫穷的环境（单管）。 接下来，我们将在单管中的延长唤醒期间以及在 睡吧这两种剧烈活动的条件几乎没有可塑性，预计会导致疲劳， 将再次与单管中的延长唤醒的那些进行比较。为了进一步将 可塑性的影响，从那些活动，我们将重复的实验，在学习突变体，其中暴露 到飞行商场不应该导致可塑性/疲劳。最后，我们将使用SBF-SEM来测试是否有 超微结构特征可以区分已经清醒的果蝇的神经元和那些 睡眠，并比较与可塑性导致疲劳的唤醒与相关的唤醒的影响， dTrpA 1介导的强烈放电导致疲劳。总而言之，这些对苍蝇的研究将补充 项目II中的小鼠，使用类似或完全相同的方法。他们将一起建立，如果睡眠和觉醒， 在单个神经元水平上受到稳态调节，如果它们留下反映 它们对单个细胞的影响和功能。