Development and function of the larval nervous system 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，也许脊索动物除外。章鱼等头足类动物的大脑和行为甚至是亚里士多德着迷的主题，而静坐的石鳖的大脑和行为最多只能被描述为初级。此外，软体动物神经系统的特殊特征（即它们的巨细胞）已被用于获得诺贝尔奖的研究。然而，我们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产生的，知之甚少。此外，从其他生物如苍蝇、蠕虫和哺乳动物中获得的神经发育知识似乎不足以解决这一问题。该应用程序建议在神经系统首次发育时检查构成神经系统的完整细胞补体，特别关注腹足类动物的幼虫阶段，这可能最能代表祖先软体动物的个体发生起源。对幼虫神经系统组成的更完整的认识将反过来指导对其功能的后续研究。对功能的理解反过来又提供了对塑造整个门的神经系统进化的力量以及其中不同类别的见解。我们将特别关注已识别的细胞和细胞类型在行为中的作用，这些行为使幼虫能够适应化学物质、光、电流和重力。最后，我们将研究软体动物神经系统形成的发育机制，特别关注神经细胞类型产生的初始步骤。在软体动物中观察到的大脑结构的多样性源于早期神经元发育机制的多样性的假设，将通过检查从墨鱼到蜗牛等动物的神经系统不同区域的起源来验证。虽然主要是为了更好地了解我们周围生命的多样性，但这项工作也对了解动物的重要幼虫阶段有影响，这些动物构成了我们海洋生态系统的主要组成部分，也是水产养殖的珍贵食物。

The nervous systems of molluscs show a diversity which surpasses that of any other phylum, except perhaps the chordates. The brains and behaviours of cephalopods such as the octopus were even the subjects of fascination for Aristotle, while both the brain and behaviour of sedentary chitons can be described only as rudimentary at best. Moreover, special characteristics of the molluscan nervous system (i.e., their giant cells) have been exploited in Nobel Prize winning research. And yet, we know very little about how the molluscan nervous system develops or how such diversity is generated. Furthermore, knowledge of neural development derived from other organisms such as flies, worms and mammals appears inadequate to resolve this issue. This application proposes to examine the full complement of cells that comprise the nervous system as it first develops, focusing particularly on larval stages of gastropods which may best represent the ontogenetic origins of ancestral molluscs. A more complete view of the components of the larval nervous system will in turn guide subsequent studies on its function. Understanding function in turn provided insights into forces shaping the evolution of the nervous system of the phylum as a whole and of the different classes within. We will particularly focus on the roles of identified cells and cell types in behaviours that allow the larvae to orient to chemicals, light, currents and gravity. Finally, we will investigate the developmental mechanisms responsible for formation of the molluscan nervous system, paying particular attention to the initial steps in generation of neuronal cell types. The hypothesis that the diversity of brain structures observed within molluscs derives from a diversity of mechanisms underlying early neuronal development will be tested by examining the origins of different regions of the nervous system in animals ranging from cuttlefish to snails. While aimed largely at a better understanding of the diversity of life around us, the work also has implications for understanding the important larval stages of animals that constitute major components of our ocean ecosystems and are also prized foods from aquaculture.