Inhibitory Cell Types and Circuits in the Lateral Hypothalamus

项目总结/摘要 该建议的目标是定义细胞的多样性，连接性和抑制神经元的功能， 下丘脑外侧区（LHA）。LHA是协调行为基本方面的关键 由于其在多个神经和体液系统交叉点的独特位置。LHA GABA能神经元 特别是已经成为唤醒、目标导向行为以及消极和消极行为的有力驱动器， 正价行为在这一广泛的抑制性LHA神经元类别中， 重要的亚群，这可能差异决定行为输出。其中重要的是 表达神经肽黑色素浓集激素（MCH）的推定抑制性神经元群体。 LHA MCH表达神经元（LHAMCH）显示出显著的功能多样性， 在整个大脑和协调广泛的生理功能和行为，包括 调节睡眠-觉醒状态、进食、动机行为、压力和记忆。然而，实验 LHAMCH神经元的操作主要在LHAMCH神经元是单片的情况下解释， 神经调节投射系统，创造了一个深刻的知识差距，其功能的来源， 多样性因此，迫切需要描述独特的细胞，电路水平和行为影响 LHAMCH多样性在上一个赠款周期，我们在实现长期目标方面取得了重大进展， 定义LHA GABA能神经元的群体结构，包括产生最多的GABA能神经元。 迄今为止，小鼠中分子上不同的LHA细胞类型的全面细胞分类学。在这里，我们将建立 通过我们对以下的研究进展：1）两个转录组学上不同的LHAMCH亚群， 差异表达神经激肽3受体（NK 3 R），神经激肽B受体（NKB）; 2）和一种新的 从中央延伸杏仁核中的NKB神经元到LHA的投射。在目标1中，我们将确定 不同的LHAMCH亚群产生投射到大脑中不同靶点的功能性子回路， 使用基于NK 3R富集的精确交叉病毒策略释放不同的神经化学物质 在LHAMCH亚群中的分布在目标2中，我们将探讨LHAMCH的差异参与是否 使用两种平行的交叉策略， 光遗传学地靶向LHAMCH亚群，然后使动物经历一系列行为 评估。在目标3中，我们将研究NKB/NK 3R信号转导在细胞中的生物学机制。 通过详细的NKB/GABA共刺激的电生理研究， 传递到LHAMCH神经元，并通过研究这些投射的行为影响。统称 拟议的实验将解决悬而未决的问题，有关细胞和电路水平的功能， LHAMCH神经元多样性，这对于LHA电路功能的机械理解是必要的， 作为确定神经精神、睡眠和代谢紊乱的治疗靶点的关键前体。

PROJECT SUMMARY/ABSTRACT The goal of this proposal is to define the cellular diversity, connectivity and function of inhibitory neurons in the lateral hypothalamic area (LHA). The LHA is a linchpin in the orchestration of fundamental aspects of behavior owing to its unique position at the intersection of multiple neural and humoral systems. LHA GABAergic neurons in particular have emerged as potent actuators of arousal, goal-directed behavior as well as both negative and positive valence behavior. Within this broad class of inhibitory LHA neurons lie poorly resolved but functionally important subpopulations, which may differentially determine behavioral output. Important among these is a population of putative inhibitory neurons that express the neuropeptide melanin-concentrating hormone (MCH). LHA MCH-expressing neurons (LHAMCH) display remarkable functional diversity, sending extensive projections throughout the brain and coordinating a broad range of physiological functions and behaviors, including the modulation of sleep-wake states, feeding, motivated behavior, stress and memory. However, experimental manipulations of LHAMCH neurons are largely interpreted in the context of LHAMCH neurons being a monolithic, neuromodulatory projection system, creating a profound knowledge gap as to the source of their functional diversity. There is, therefore, a critical need to delineate the unique cellular, circuit-level and behavioral impact of LHAMCH diversity. In the previous grant cycle, we made significant progress towards our long-term goal of defining the population structure of LHA GABAergic neurons, including the generation of the most comprehensive cellular taxonomy to date of molecularly distinct LHA cell types in the mouse. Here, we will build upon that progress through our investigation of: 1) two transcriptomically-distinct LHAMCH subpopulations that differentially express the neurokinin 3 receptor (NK3R), the receptor for neurokinin B (NKB); 2) and a novel projection from NKB neurons in the central extended amygdala to the LHA. In Aim 1, we will determine whether distinct LHAMCH subpopulations give rise to functional sub-circuits that project to different targets in the brain and release different neurochemicals using a precise intersectional viral strategy based on the enrichment of NK3R in one LHAMCH subpopulation over the other. In Aim 2, we will explore whether differential engagement of LHAMCH subpopulations elicits distinct behavioral repertoires using two parallel intersectional strategies for optogenetically targeting LHAMCH subpopulations and then subjecting animals to a suite of behavioral assessments. In Aim 3, we will investigate the biological mechanisms underlying NKB/NK3R signaling in the central extended amygdala–LHA circuit through a detailed electrophysiological investigation of NKB/GABA co- transmission onto LHAMCH neurons, and by studying the behavioral impact of these projections. Together, the proposed experiments will address outstanding questions concerning the cellular and circuit-level functions of LHAMCH neuron diversity, which is necessary both for a mechanistic understanding of LHA circuit function, and as a critical precursor for identifying therapeutic targets for neuropsychiatric, sleep and metabolic disorders.