Optogenetic studies of mouse olfaction

小鼠嗅觉的光遗传学研究

• 批准号: 8371241
• 负责人: VENKATESH N MURTHY
• 金额: $ 33.92万
• 依托单位: HARVARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8371241
• 关键词: Afferent Neurons; Aging; Alzheimer' s Disease; Animals; Architecture; Area; Autistic Disorder; Axon; Behavior; Brain; Brain Diseases; Brain Stem; Breathing; Breeding; Cells; Characteristics; Chemicals; Code; Decision Making; Dendrites; Devices; Disease; Dissection; Elements; Feedback; Food; Functional disorder; Future; Goals; Health; Human; In Vitro; Indium; Individual; Interneurons; Investigation; Ion Channel; Lateral; Light; Mammals; Methods; Metric; Molecular Genetics; Mus; Neurons; Nose; Odorant Receptors; Odors; Olfactory Cortex; Olfactory Epithelium; Optics; Output; Partner in relationship; Pattern; Pheromone; Positioning Attribute; Preparation; Process; Property; Proteins; Reagent; Research; Resolution; Retina; Retinal Ganglion Cells; Sampling; Sensory; Single Parent; Slice; Smell Perception; Solutions; Specificity; Stimulus; Structure; Surface; Synapses; System; Technology; Testing; Time; Transgenic Mice; Vertebrates; Visual; Visual system structure; digital; extracellular; granule cell; information processing; millisecond; mouse model; nervous system disorder; neural circuit; novel; olfactory bulb; optogenetics; piriform cortex; postsynaptic; public health relevance; receptive field; receptor; relating to nervous system; research study; response; sensory system; theories; tool; visual receptive field; vomeronasal organ

DESCRIPTION (provided by applicant): The function of a neural circuit is constrained by the properties of individual neurons and their wiring. In many sensory systems, the responses of the circuit elements vary systematically with physical position, leading to a topographic representation of the stimulus space. Sensory representation in the olfactory system has been harder to decipher, in part due to the difficulty in finding appropriate metrics to characterize the odor space and in sampling this space densely. Progress has also been slowed by technological limitations in probing and controlling individual circuit elements in early olfactory circuits. In this proposal, we aim to develop new methods that will greatly aid the dissection of functional neural circuits in the olfactory system in mice. Mice rely on olfaction to find food, choose mates and avoid predators. In mammals, olfactory sensory neurons send their axons to the olfactory bulb (OB), where there is a characteristic physical layout of inputs in the glomerular layer. Each glomerulus receives convergent afferents from a large number of olfactory sensory neurons expressing the same odorant receptor, so each point on the surface of the OB has a specific chemical response spectrum. The principal neurons in the OB, the mitral and tufted (M/T) cells, typically have a single primary dendrite that projects to a single glomerulus. M/T cells also receive lateral GABAergic inputs from a variety of interneurons in the glomerular and external plexiform layers, thus allowing them to sample information from several functionally diverse glomeruli. Odor processing in the OB is also strongly modulated by feedback from the cortex as well as brainstem neuromodulatory centers. Here, we propose to develop new reagents and methods that will accelerate the pace of research into mammalian olfaction. Our experiments will be guided by three specific aims. Aim 1: To generate transgenic mouse lines that express the light-activated ion channel channelrhodopsin specifically in olfactory sensory neurons, rendering the input layer of the olfactory bulb (glomeruli) optically excitable. Aim 2: To demonstrate the feasibility of using this mouse model to study functional connectivity in the OB and its downstream target areas using in vitro slice preparation and digital mirror device technology. Aim 3: To demonstrate the feasibility of constructing glomerular receptive fields of neurons in the OB and its target brain areas in the intact, freely breathing mouse. Tools developed here will help advance our understanding of odor coding. In addition, since the olfaction is often used as a sensory gateway to study higher brain function such as decision making, our tools will also have broader use. Finally, by crossing these "opto-olfactory" mice with other mouse models of disease, we can catalyze studies of sensory dysfunction in brain disorders such as autism and Alzheimer's disease.

描述（由申请人提供）：神经回路的功能受单个神经元及其接线的特性的约束。在许多感官系统中，电路元件的响应随物理位置的系统变化，从而导致刺激空间的地形表示。嗅觉系统中的感官表示很难破译，部分原因是很难找到适当的指标来表征气味空间以及密集地对此空间进行采样。在早期嗅觉电路中，探测和控制单个电路元素的技术限制也使进展减慢了。在此提案中，我们旨在开发新方法，以极大地帮助小鼠嗅觉系统中功能性神经回路的解剖。 小鼠依靠嗅觉寻找食物，选择伴侣并避免捕食者。在哺乳动物中，嗅觉感觉神经元将其轴突发送到嗅球（OB），在肾小球层中有特征性的输入物理布局。每个肾小球都会从表达相同气味受体的大量嗅觉感觉神经元中接收收敛传入，因此OB表面上的每个点都有特定的化学反应谱。 OB中的主要神经元，二尖瓣和簇状细胞（M/T）细胞通常具有单个原发性树突，可将单个肾小球投射到单个肾小球上。 M/T细胞还从肾小球和外部丛状层中的多种神经元中接收侧向GABA能输入，从而使它们可以从几个功能多样的肾小球中采样信息。 OB中的气味处理也受到皮层和脑干神经调节中心的反馈的强烈调节。 在这里，我们建议开发新的试剂和方法，以加快哺乳动物嗅觉研究的速度。我们的实验将以三个特定目标指导。 AIM 1：生成表达嗅觉感觉神经元中的光激活离子通道旋转蛋白的转基因小鼠系，从而使嗅球（glomeruli）的输入层具有光学上的兴奋性。 AIM 2：证明使用该鼠标模型使用体外切片准备和数字镜设备技术研究OB及其下游目标区域中的功能连接的可行性。目的3：证明在完整，自由呼吸的小鼠中，在OB及其目标大脑区域中构建神经元的肾小球接受场的可行性。 这里开发的工具将有助于提高我们对气味编码的理解。此外，由于嗅觉通常被用作研究更高的大脑功能（例如决策）的感觉门户，因此我们的工具也将更广泛地使用。最后，通过将这些“光电效应”小鼠与其他小鼠疾病模型跨越，我们可以催化对自闭症和阿尔茨海默氏病等脑部疾病中感觉障碍的研究。