CAREER: Dissecting the whole-brain circuit mechanisms for oxytocinergic control of pain avoidance behavior

疼痛的体验触发了一系列不同的生理和行为反应，帮助动物将受伤的可能性降至最低，并使其生存概率最大化。因此，描述神经回路如何对痛苦的经历做出反应，对于更好地理解大脑功能的一个关键方面非常重要。为了实现这一目标，该项目将研究斑马鱼幼体的疼痛处理过程。斑马鱼是一种常见的实验室模式生物，其大脑与人类的许多基本特征相同，但又足够小，可以以独特而强大的方式进行研究和操作。这些特征将使这项工作能够在整个大脑水平上研究产生神经递质催产素的细胞如何塑造疼痛的神经表现和行为反应。由于催产素产生细胞高度保守，被认为在所有脊椎动物的疼痛处理中都很重要，因此这项工作提供的见解将有助于建立跨物种通用的神经回路功能模型。因此，这项工作将通过促进我们对神经系统处理疼痛的基本方式的理解来服务于国家利益，这不仅将使我们更多地了解大脑一般是如何工作的，而且还可能导致对疼痛管理的意想不到的洞察。此外，使用简单的模式生物体将使这项工作中开发的资源和专业知识能够轻松地应用于高中、大学和研究生水平的各种有计划的教育活动。技术摘要虽然脊椎动物下丘脑中的催产素能神经元以其在生殖、学习和社会行为中的作用而闻名，但越来越多的证据表明，OXT也是疼痛反应的重要调节器。与它的其他功能一样，oxt在疼痛中的作用是综合的，共同影响各种生理和神经元事件，从而影响行为。虽然以前在哺乳动物身上的研究强调了oxt的止痛和减轻恐惧的作用，但道格拉斯实验室最近发现，在斑马鱼的幼体中，急性疼痛激活oxt神经元是促进防御性“逃跑”行为的中心事件。Oxt在避免疼痛中的作用背后的电路机制，oxt神经元释放的其他神经递质的贡献，以及底层网络的功能架构都尚不清楚。目前的提议将结合全脑解剖学、功能成像、电路标记和行为，使用遗传和光遗传操作，以确定OXT神经元的细胞靶点，这些细胞靶点介导其对疼痛避免的影响，并表征OXT神经元群体中关于行为功能的解剖异质性。与此同时，该项目利用其核心专业知识和资源，为高中生开设了一门利用斑马鱼作为神经科学模式生物的暑期课程，以及一门密集的显微镜研究生课程。

General AbstractThe experience of pain triggers a host of different physiological and behavioral responses that help an animal minimize the potential for injury and maximize its probability of survival. Describing how neural circuits respond to painful experience is therefore important for better understanding a crucial aspect of brain function. To accomplish this goal, this project will examine pain processing in the larval zebrafish, a common laboratory model organism whose brain shares many essential features with that of humans while being small enough to study and manipulate in uniquely powerful ways. These features will enable this work to investigate how cells that produce the neurotransmitter oxytocin shape the neural representation of and behavioral response to pain, at the level of the entire brain. Because oxytocin-producing cells are highly conserved and thought to be important in pain processing in all vertebrates, the insight provided by this work will help to create models for neural circuit function that generalize across species. The work will therefore serve the national interest by advancing our understanding of the fundamental ways that nervous systems process pain, which will not only tell us more about how brains work, in general, but which could also lead to unexpected insights into pain management. Additionally, the use of a simple model organism will enable resources and expertise developed in this work to be easily applied to a variety of planned educational activities at the high school, college, and graduate levels.Technical AbstractWhile oxytocinergic neurons in the vertebrate hypothalamus are best known for their roles in reproduction, learning, and social behavior, an emerging body of evidence shows that OXT is also an important modulator of the pain response. As with its other functions, OXT's role in pain is integrative, effecting diverse physiological and neuronal events in concert to influence behavior. While previous work in mammals has emphasized the analgesic and fear-attenuating effects of OXT, the Douglass lab has recently discovered that, in the larval zebrafish, activation of OXT neurons by acute pain is a central event in promoting defensive "flight" behaviors. The circuit mechanisms behind OXT's role in pain avoidance, the contribution of other neurotransmitters released by the OXT neurons, and the functional architecture of the underlying networks all remain unknown. The current proposal will use genetic and optogenetic manipulations in combination with whole-brain anatomy, functional imaging, circuit labeling, and behavior, in order to identify the cellular targets of OXT neurons that mediate their effects on pain avoidance and characterize anatomical heterogeneity within the population of OXT neurons with respect to behavioral function. In parallel, the project leverage its core expertise and resources to create a summer course for high school students in the use of zebrafish as a model organism for neuroscience, and an intensive graduate course in microscopy.