Active flow sensing during helical swimming in a ciliary microswimmer

这一基础研究项目将对海洋幼虫的微型神经系统以及它如何在具有动态流体流动的水生生境中发挥作用进行新的系统水平的理解。它提出了一个将生物学和物理学的思维和方法紧密结合起来的跨学科研究框架。水生动物感知周围水流并对其做出反应的能力对它们的生存至关重要。例如，鱼可以探测到其他鱼移动产生的水流，这种感觉使它们能够形成大型鱼群。其他水生动物能够通过感知捕食者产生的流动扰动来躲避接近的捕食者，如水母。鱼和其他海洋浮游生物也可以感知水流的方向，并重新定位以逆流游泳。这种上游游动被称为流变性，也是精子细胞导航到卵子进行内部受精的机制。动物是如何感知和反应流动的，目前还不完全清楚。生物体依赖于环境刺激和自身运动之间的复杂耦合。我们的目的是了解海洋生物中流动反应的神经元和行为控制。我们将研究一种名为Platynereis的海洋沙虫幼虫的流动感觉。Platynereis可以在实验室培养，我们的团队已经建立了这种动物，用于实验研究浮游动物行为的神经机制。我们最近发现，这种鞭虫的幼虫有专门对液体流动做出反应的神经元。在这个项目中，我们将使用先进的显微镜技术来揭示这些神经元是如何与神经系统的其他部分相连的，并用数据驱动的计算机建模来揭示流感如何改变幼虫的螺旋游泳行为。我们将创建定制的房间和竞技场，以测试单个幼虫如何对受控的流体流动和微环境做出反应。沙蚕幼虫的尺寸只有五分之一毫米，这个小尺寸将使我们能够以更大动物尚不可行的细节水平来研究流动感觉。由于Platynereis显示出许多与脊椎动物相似的神经元和分子特征，我们的研究将揭示动物流动感的一般原理。

This fundamental research project will develop a new systems-level understanding of a miniature nervous system in a marine larva and how it functions in aquatic habitats with dynamic fluid flows. It proposes an interdisciplinary research framework that tightly integrates biological and physical thinking and approaches. The ability for aquatic animals to sense and respond to the movement of water around them can be important for survival. For example, fish can detect flows generated by the movement of other fish, and this sense allows them to form large schools. Other aquatic animals are able to evade approaching predators such as jellyfish by sensing the flow perturbations generated by the predator. Fish and other marine plankton can also sense the flow direction and reorient themselves to swim against the flow. This upstream swimming is known as rheotaxis, and is also the mechanism by which sperm cells navigate towards the egg for internal fertilization. How animals sense and respond to flow is incompletely understood. Organisms rely on an intricate coupling between the environmental stimulus, and their own self-movement. Our aim is to understand the neuronal and behavioural control of flow responses in a marine organism. We will study flow sensation in the larvae of a marine ragworm called Platynereis. Platynereis can be cultured in the laboratory and our team has established this animal for the experimental study of the neural mechanisms of zooplankton behaviour. We have recently discovered that the larvae of this ragworm have neurons that respond specifically to fluid flow. In this project, we will use advanced microscopy techniques to uncover how these neurons connect to the rest of the nervous system and data-driven computer modelling to reveal how flow sensation alters the larva's helical swimming behaviour. We will create custom chambers and arenas to test how single larvae respond to controlled fluid flows and microenvironments. Ragworm larvae measure only one fifth of a millimetre and this small size will allow us to investigate flow sensation at a level of detail that is not yet feasible for larger animals. Since Platynereis shows many neuronal and molecular characteristics that are similar to those found in vertebrates, our study will uncover general principles of flow sensation in animals.