Activation and connectivity in the olfactory system of a basal vertebrate

基础脊椎动物嗅觉系统的激活和连接

• 批准号: RGPIN-2014-03916
• 负责人: Zielinski, Barbara
• 金额: $ 1.89万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587493
• 关键词: Activation; connectivity; olfactory; system; basal

In many vertebrates, olfactory sensory input takes place in more than one location within the nasal cavity, and odour information is processed in a spatially precise manner in the olfactory bulb. However, the rationale behind the organization of the olfactory subsystems is not well understood. The objective of this research program is to investigate the odor sensitivity, biochemical profile and neural connectivity in subdivisions of the peripheral olfactory organ and the olfactory bulb in the lamprey, a basal vertebrate that diverged from the main vertebrate line of evolution over 500 million years ago. While teleost fish smell hundreds of odours, and mammals respond to thousands of odorous molecules, the lamprey has an olfactory repertoire of a few dozen odourants. Yet olfaction is a key sensory modality, as pheromones direct lampreys during spawning migration and reproductive behaviour. These characteristics enable the lamprey to be utilized as a reductionist model for investigating vertebrate olfaction. We have recently utilized electrophysiology of an in vitro lamprey nose-brain prep to characterize the odour activation map of the olfactory bulb. The lateral region responds to amino acids, yet the olfactory sensory neuron population that projects into this bulbar region is unknown. We will utilize neuronal tract tracing to find the peripheral location and the cell morphology of these olfactory sensory neurons; and we will investigate the signal transduction pathways of these olfactory sensory neurons through optical imaging and electrophysiology. Tract tracing will be used to investigate the dendritic arbors of lateral bulbar projection neurons, to examine the degree of convergence of the neurons that convey amino acid olfaction. While the lateral region of the olfactory bulb is stimulated by amino acids, there is a less clear picture of the spatial response map to pheromones. We will investigate if there are specific regions devoted to specific pheromones associated with migration and reproduction. Tract tracing will be used to identify the peripheral location of the pheromone sensing neurons, the central projections and the corresponding bulbar projection neurons. In derived vertebrates, olfactory sensory neuronal subtypes express specific conductance channels that are partnered with signal transduction pathways. The recent annotation of the sea lamprey genome opens up opportunities for investigating the expression of specific conductance channels expressed by the different populations of sea lamprey olfactory sensory neurons. This information is important for defining the lamprey olfactory subsystems in terms of the general vertebrate model. This research program probes for commonality and divergence in the evolution of the vertebrate nervous system. It is significant because it will contribute knowledge of the how and why of olfactory sensory input and the ensuing central connections. On a broader scale, this research will contribute to knowledge regarding the evolution of the brain and how the vertebrate brain handles information from diverse chemical stimuli. Translation of this research will directly benefit wildlife management of the invasive sea lamprey in the Great Lakes, and endangered populations in Europe and the North American west coast.

在许多脊椎动物中，嗅觉感觉输入发生在鼻腔内的一个以上的位置，并且气味信息在嗅球中以空间精确的方式进行处理。 然而，嗅觉子系统的组织背后的原理还没有很好地理解。 这项研究计划的目的是调查的气味敏感性，生化档案和神经连接的外周嗅觉器官和嗅球的分支七鳃鳗，一个基础的脊椎动物，偏离了超过5亿年前的主要脊椎动物进化线。 硬骨鱼能闻到数百种气味，哺乳动物能对数千种气味分子做出反应，而七鳃鳗的嗅觉系统只有几十种气味。 然而，嗅觉是一个关键的感觉方式，作为信息素直接七鳃鳗在产卵迁移和生殖行为。 这些特点使七鳃鳗被用作研究脊椎动物嗅觉的简化模型。 我们最近利用电生理学的体外七鳃鳗鼻脑制备表征嗅球的气味激活地图。 外侧区对氨基酸有反应，但投射到延髓区的嗅觉感觉神经元数量尚不清楚。 我们将利用神经束追踪来寻找这些嗅觉感觉神经元的外周定位和细胞形态;并通过光学成像和电生理来研究这些嗅觉感觉神经元的信号转导通路。 将使用束追踪来研究外侧球投射神经元的树突乔木，以检查传递氨基酸嗅觉的神经元的会聚程度。 虽然嗅球的侧部区域被氨基酸刺激，但对信息素的空间反应图不太清楚。 我们将调查是否有专门的特定区域与迁移和繁殖相关的特定信息素。束追踪将被用来确定信息素感觉神经元的外周位置，中央投射和相应的延髓投射神经元。 在衍生的脊椎动物中，嗅觉感觉神经元亚型表达与信号转导途径合作的特异性传导通道。 最近的注释海七鳃鳗基因组开辟了机会，调查的特定电导通道的表达所表达的不同群体的海七鳃鳗嗅觉感觉神经元。 这一信息是重要的定义七鳃鳗嗅觉子系统的一般脊椎动物模型。 本研究计画探讨脊椎动物神经系统演化的共性与差异。 这是重要的，因为它将有助于知识的嗅觉感觉输入和随之而来的中央连接的方式和原因。在更广泛的范围内，这项研究将有助于了解大脑的进化以及脊椎动物大脑如何处理来自不同化学刺激的信息。 这项研究的翻译将直接有利于野生动物管理的入侵海七鳃鳗在五大湖，濒危种群在欧洲和北美西海岸。