Neuroethology of odour-based navigation in aquatic gastropods

我的长期目标是了解动物如何使用多种导航策略移动，重点是腹足类动物基于气味的导航。 研究人员花了相当大的努力来了解动物如何通过向上爬来响应吸引人的气味羽流，跟随气味源。然而，在自然界中，流动方向经常变化。我们对这种流动变化对动物导航的影响知之甚少。我的第一个目标是探索缓慢移动的鼻涕虫和蜗牛如何在两个不同的层面上科普流动的变化：一个应该被跟踪，另一个可能应该被忽略。首先，随着整体流动方向的变化，气味羽流也会发生变化，动物必须跟踪这些变化以找到气味源。我和我的学生将使用现场视频记录和流速计来探索裸鳃海蛞蝓对不同程度的流动变化的反应，凭经验确定蛞蝓决定整体流动方向的时间尺度。第二，取决于流速，由不变的整体流携带的气味羽流将涉及湍流-由水穿过基底的运动产生的流动方向的较小尺度变化。如果是这样，动物应该避免跟随这种局部流动变化，只对潜在的整体流动方向做出反应。在这些实验中，我们将使用淡水蜗牛Stagnalis来测试它们对局部湍流的反应。通过对这两个物种的研究，我们将了解动物如何区分整体流动方向的变化与湍流的变化。我的第二个目标是为探索动物的神经系统如何产生这些行为奠定基础。腹足类的实验顺从性和简单的神经系统使我们能够确定单个神经元在线索检测中的作用以及随后的动物爬行控制机制。然而，在我们对导航所涉及的感觉系统的理解方面仍然存在很大的差距。因此，我和我的学生将使用各种方法来记录动物感觉器官中神经系统的解剖结构。我的第三个目标是特别关注感觉神经元和回路的功能，这些神经元和回路检测和处理T细胞中的流向。狄俄米底亚。这种感觉处理必须作为控制导航的大脑回路的关键输入，但我们对任何动物的流动方向的检测知之甚少。我们的研究结果将指导我未来的研究计划，研究腹足类动物产生不同导航策略的神经回路。 此外，通过比较整个动物王国的结果，我们可以更广泛地理解导航和其他行为背后的神经机制。最后，通过这项研究，我的学生将学习各种基本技能和可转移的技术，他们可以在他们的学术或职业生涯中应用。

My long-term goal is to understand how animals use multiple navigation strategies to move, focusing on odour-based navigation in gastropods. Researchers have spent considerable effort to understand how animals respond to attractive odour plumes by crawling upstream, following the flow to an odour source. Yet, in nature, flow directions frequently change. We know much less about the consequences of this flow variability on animal navigation. My first objective is to explore how slow-moving slugs and snails cope with flow variability at two different levels: one that should be tracked, and another that likely should be ignored. First, as bulk flow direction shifts, so do odour plumes, and animals must track these shifts to find odour sources. My students and I will use field video recording and current meters to explore how responsive the nudibranch Tritonia diomedea is to shifting flows of varying degrees, empirically determining the time scale over which the slugs determine bulk flow direction. Second, depending on flow speeds, an odour plume carried by unchanging bulk flow will involve turbulence - smaller scale variations in flow direction generated by water movement across the substrate. If so, the animals should avoid following this local flow variation, responding only to the underlying bulk flow direction. For these experiments, we will use the freshwater snail Lymnaea stagnalis to test their responses to local turbulence. From the work on both species, we will learn how the animals may differentiate between changes in bulk flow direction versus changes from turbulent flow. My second objective is to lay a foundation to explore how the animals' nervous system produces these behaviours. The experimental amenability and simpler nervous system of gastropods allow us to determine the roles of single neurons in cue detection and the subsequent control mechanisms of the animals' crawling. However, there remains a substantial gap in our understanding of the sensory systems involved in navigation. Thus, my students and I will use a variety of methods to document the anatomy of the nervous system in the animals' sense organs. My third objective is to focus specifically on the function of the sensory neurons and circuits that detect and process flow direction in T. diomedea. This sensory processing must serve as a key input into the brain circuits that control navigation, yet we know very little about the detection of flow direction in any animal. Our results will guide future aspects of my research program studying the neural circuits that produce the different navigational strategies in gastropods. Moreover, by comparing results from across the animal kingdom, we can achieve a broader understanding of the neural mechanisms underlying both navigation and other behaviours. Finally, through this research, my students will learn a variety of fundamental skills and transferable techniques they can apply in their academic or professional careers.