The function of the primary olfactory pathway

鱼类在生活的许多方面都依赖嗅觉——躲避捕食者、繁殖、觅食甚至抚育亲代。气味浓度，低至皮摩尔范围，能够产生戏剧性的行为变化。尽管在理解嗅觉系统方面已经取得了很大的进步，但关于其组织和功能的基本问题仍未得到解答。我们的长期目标是了解完全生活在水生环境中的脊椎动物嗅觉通路的功能不同子集的组织和发展，以及这些子系统在进化过程中是如何产生的。根据这一观点，我们将把重点放在嗅觉感觉神经元亚群和附属嗅觉器官上，这是一种解剖学上与七鳃鳗（一种无颌鱼，是颌口鱼的姐妹群）的鼻子结构，可能具有化学感觉特性。我们将验证以下假设：1)这些细胞具有不同的超微结构、功能、生化和受体特性；2)在嗅球内不同空间的肾小球区域传递突触信息。最后，我们将采用基于活性的mRNA组织学方法来研究携带与特定嗅觉行为相关信息的嗅觉通路的发展。除了为渔业和水产养殖业提供有关鱼类嗅觉能力和发育的信息外，本研究还为了解鱼类嗅觉系统的功能和进化提供了重要的模型。了解嗅觉通路中细胞亚群的神经解剖学、组成、功能和发育，将为未来研究嗅觉感觉输入对复杂行为反应的机制奠定基础。

Fish rely on olfaction for many facets of life - predator avoidance, reproduction, feeding and even parental care. Odour concentrations, as low as the picomolar range, are able to generate dramatic behavioural changes. Although great strides have been made towards understanding the olfactory system, basic questions regarding its organization and function remain unanswered. Our longterm goals are to understand the organization and development of functionally distinct subsets of the olfactory pathway in vertebrates that live entirely in an aquatic environment, and how these sub-systems arose during evolution. Consistent with this idea, we will focus on subpopulations of olfactory sensory neurons, and the accessory olfactory organ, an anatomically linked nasal structure with possible chemosensory properties in the lamprey, a jawless (agnathan) fish of ancient origin that is a sister group to the gnathostomes. We will test the hypotheses that these cells 1) possess distinct ultrastructural, functional, biochemical and receptor properties, 2) transmit synaptic information in spatially distinct glomerular territories in the olfactory bulb. Lastly, we will take an activity- based mRNA histological approach for investigating the development of an olfactory pathway that carries information associated with a specific olfactory behaviour. In addition to providing information for the fisheries and aquaculture industry regarding fish olfactory capabilities and development, this research on fish serves as an significant model for understanding the function and evolution of the olfactory system. Understanding the neuroanatomy, composition, function and development of the cellular subpopulations within the olfactory pathway, will lay a foundation for future studies into unraveling the mechanisms of olfactory sensory input on complex behavioural responses.