Form and function of the olfactory and larval nervous systems in molluscs

软体动物的神经系统表现出的多样性超过了任何其他门，也许除了脊索动物。章鱼等头足类动物的大脑和行为是亚里士多德着迷的对象，而那些久坐不动的石鳖充其量只能被描述为初级的。然而，我们目前对软体动物的神经系统是如何发育的，以及这种多样性是如何通过进化产生的知之甚少。此外，来自模式生物如苍蝇，蠕虫和某些脊椎动物的神经发育的知识似乎不足以解决这个问题。本申请提出了两条研究路线，旨在更好地了解软体动物的神经进化和发育。第一行将研究嗅觉系统，并寻找感觉处理的基本单位（肾小球），如节肢动物和脊椎动物中所描述的，但在这两个群体之外基本上是未知的。对软体动物的研究不仅会告诉我们嗅觉是如何在这些动物中进化的，而且可能会为我们自己的嗅觉提供见解。第二条线涉及幼虫神经系统的研究，它在早期生命中起着关键作用，并提供了一个支架上建立成人神经系统。软体动物的幼虫神经系统与动物界的幼虫神经系统有相似之处，因此可以作为比较不同体型动物的基础。我们的工作重点是识别和形态的细胞，使用乙酰胆碱和组胺作为递质，然后检查他们的角色，让幼虫定向到化学品，光，电流和重力的行为。这两条研究线将依赖于使用多种组合染色技术，再加上高分辨率显微镜和3D重建。软体动物是散斑轮藻门中最具多样性和最大的一门，从目前的模式物种中提供了一个重要而独特的视角。虽然这项工作的主要目的是更好地了解我们周围的生命多样性，但它也对理解作为海洋生态系统主要组成部分的幼虫和成年软体动物，甚至是水产养殖的珍贵食物具有影响。

The nervous systems of molluscs show a diversity which surpasses any other phylum, except perhaps the chordates. The brains and behaviours of cephalopods like the octopus were subjects of fascination for Aristotle, while those of sedentary chitons can be described only as rudimentary at best. And yet, we currently know very little about how the molluscan nervous system develops or how such diversity is generated through evolution. Moreover, knowledge of neural development derived from model organisms such as flies, worms and certain vertebrates appears inadequate to resolve this issue. This application proposes two lines of research aim at better understanding neural evolution and development within the molluscs. The first line will investigate the olfactory system and look for the basic units of sensory processing (glomeruli) as described in arthropods and vertebrates but largely unknown outside these two groups. Work on molluscs will not only inform us about how olfaction may have evolved in these animals but may provide insights into our own sense of smell. The second line involves investigation of the larval nervous system, which plays a critical role in early life and provides a scaffold on which the adult nervous system is built. The larval nervous system of molluscs is known to share similarities with larval nervous systems from across the animal kingdom and thus serves as a basis for comparison of animals with otherwise diverse body forms. Our work focuses on identification and morphology of cells which use acetylcholine and histamine as transmitters, and then examines their roles in behaviours that allow larvae to orient to chemicals, light, currents and gravity. Both lines of research will depend upon the use of multiple, combinational staining techniques coupled with high resolution microscopy and 3D reconstruction. As both the most varied and also the largest phylum in the Lophotrochozoa, the molluscs offer an important and unique perspective from current model species. While aimed largely at a better understanding of the diversity of life around us, the work also has implications for understanding larval and adult molluscs as major components of our ocean ecosystems and even as prized foods from aquaculture.