Development and function of the larval nervous system in molluscs

软体动物的神经系统表现出超过任何其他门的多样性，也许除了脊索动物。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对象，而久坐不动的石鳖的大脑和行为充其量只能被描述为初级的。此外，诺贝尔奖获得者的研究还利用了软体动物神经系统的特殊特征(即它们的巨细胞)。然而，我们对软体动物神经系统如何发育或这种多样性是如何产生的知之甚少。此外，来自苍蝇、蠕虫和哺乳动物等其他生物的神经发育知识似乎不足以解决这个问题。这项应用建议在神经系统首次发育时检查组成神经系统的全部细胞，特别是腹足类幼虫阶段，这可能最能代表祖先软体动物的个体发育起源。对幼虫神经系统组成的更全面的了解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和内部不同等级的神经系统进化的力量的洞察。我们将特别关注已识别的细胞和细胞类型在使幼虫适应化学物质、光线、电流和重力的行为中的作用。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来自于早期神经元发育的多种机制的假设，将通过研究从乌贼到蜗牛等动物神经系统不同区域的起源来检验。虽然这项工作主要是为了更好地了解我们周围生命的多样性，但也对了解动物的重要幼虫阶段有影响，这些幼虫是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.