Neuroethology of navigation in Tritonia

我的总体目标是了解动物如何使用多种导航策略移动。 我和我的学生将通过专注于海蛞蝓Tritonia diomedea基于气味的导航来解决这个问题。 人们花了相当大的努力来了解动物如何对有吸引力的气味羽流做出反应，以找到气味源。 各种研究表明，鼻涕虫和其他动物在这个过程中并不只使用气味。 相反，气味的存在刺激动物向上爬，跟随气味源的流动。 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。 我的前两个目标是探索蛞蝓如何在两个不同的水平上科普流动的变化：一个水平是为了到达气味源而应该跟踪的水平，另一个水平是为了成功导航而应该忽略的水平。首先，当栖息地中的整体流动方向发生变化时，气味羽流也会发生变化。 动物必须跟踪携带气味羽流的这些变化，以找到气味源。 我和我的学生将使用现场视频记录来探索Tritonia对不同程度的流动的反应。 第二，在由不变的整体流动携带的气味羽流内部，穿过海底的水运动在流动方向上产生较小规模的变化。 这种湍流不提供用于寻找气味源的有用信息，并且应该被忽略。 蛞蝓的运动表明它们可能科普湍流，但还没有实验验证这种可能性。 因此，我还将测试段塞对更精细的流动变化的响应程度，从而深入了解段塞如何区分整体流动方向的变化与湍流的变化。 我的最终目标是为探索鼻涕虫的神经系统如何产生这些行为奠定基础。 Tritonia的实验顺从性和简单的神经系统允许实验测试单个神经元在线索检测中的作用以及随后的鼻涕虫爬行控制机制。 我打算研究神经系统感觉成分的结构和功能，以及测试哪些神经元直接控制气流中气味刺激的转弯。 这两个组件分别作为控制导航的神经元回路的输入和输出，其结果将指导未来研究该回路如何产生不同导航策略的工作。 更一般地说，通过将这些结果与来自整个动物王国的结果进行比较，我们可以对导航行为背后的神经机制有更广泛的理解。 此外，这里使用的方法也适用于神经科学的其他领域，我的学生将在学术或职业生涯中获得宝贵的技能。

My overall goal is to understand how animals use multiple navigation strategies to move.  My students and I will tackle this problem by focusing on odour-based navigation in the sea slug Tritonia diomedea. Considerable effort has been spent understanding how animals respond to attractive odour plumes to find odour sources.  A variety of studies have shown that the slugs and other animals do no use odours alone for this process.  Instead, the presence of odours stimulate the animals to crawl upstream, following the flow to the 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 two objectives are to explore how the slugs cope with flow variability at two different levels: one level that should be tracked in order to reach the odour source, and another level that should probably be ignored for successful navigation. First, as bulk flow direction changes in a habitat, so too do odour plumes.   Animals must track these changes in the flow carrying the odour plume to find odour sources. My students and I will use field video recordings to explore how responsive Tritonia is to shifting flows of varying degrees. Second, inside an odour plume carried by unchanging bulk flow, water movement across the sea floor generates smaller scale variations in flow direction. This turbulence does not provide useful information for finding the odour source, and should be ignored.  The slugs show movements that suggest they may be adapted to cope with the turbulence, but there has been no experimental verification of this possibility.  Consequently, I will also test for how responsive the slugs are to finer flow variations, and thus gain insight into how the slugs may differentiate between changes in bulk flow direction versus changes from turbulent flow. My final objective is to lay a foundation for exploration of how the slugs' nervous system produces these behaviours. The experimental amenability and simpler nervous system of Tritonia allow experiments to test the roles of single neurons in cue detection and the subsequent control mechanisms of the slugs' crawling. I propose to study the structure and function of the sensory components of the nervous system, as well as test which neurons directly control turns stimulated by odours in flow. These two components serve as the input and output respectively for the circuit of neurons that controls navigation, and the results will guide future work studying how that circuit functions to produce the different navigational strategies. More generally, by comparing these results to those from across the animal kingdom, we can achieve a broader understanding of the neural mechanisms underlying navigation behaviour. Moreover, the methods used here are applicable to other areas of neuroscience, and my students will acquire valuable skills as they continue in academic or professional careers.