Comparative and Computational Approaches to the Evolution of Myelin

对威胁的快速行为反应对于遭受高捕食风险的动物的生存至关重要。 有两种方法可以缩短威胁刺激和逃避反应之间的延迟，这两种方法都是通过增加神经冲动沿着神经轴突的传导速度：轴突扩张和轴突周围的髓鞘。 虽然髓磷脂在脊椎动物中最为知名，但它也存在于两种甲壳类动物中。 这两个无脊椎动物群体提供了了解髓鞘结构-功能关系的机会，因为：1）可以比较密切相关的有髓鞘和无髓鞘形式; 2）神经细胞可以从一个个体到下一个个体重新识别，3）髓鞘的发育可以在所有发育阶段的识别细胞中进行跟踪。 在这个项目中，生理和计算方法将被用于比较的结构和功能分析的髓鞘在两个甲壳类动物组：软甲纲和哲水蚤桡足类。 髓磷脂在这两组中独立进化，但它在两者之间共享许多特征，同时在结构和起源上不同。 一些甲壳类动物在发育过程中从完全无髓鞘的神经系统过渡到完全有髓鞘的神经系统，因此提供了一个很好的模型来研究不完全形成的髓鞘中的神经冲动传导。 对桡足类和软介类髓鞘结构和功能的共同性进行研究，将为脊椎动物髓鞘的功能和进化提供新的认识。 这项研究将开始回答髓磷脂是如何以及为什么进化的问题。该项目将培训年轻的本科科学家进行跨学科生物学和团队研究，建立科学，技术，工程和数学的多样性;并为公众提供用于教育和数据挖掘目的的显微图像。 该项目的博士后学员将接受透射电子显微镜材料的准备和检查、细胞外电生理刺激和记录技术以及神经元功能的计算建模方面的教育。

Rapid behavioral responses to a threat are critical for the survival of animals subjected to high predation risk. Two methods have evolved to shorten the delay between a threatening stimulus and an escape response, both by increasing the conduction velocity of nerve impulses along nerve axons: axon gigantism and myelin sheaths around the axons. Although myelin is best known in vertebrates, it is also found in two crustacean groups. These two invertebrate groups provide opportunities to understand structure-function relationships in myelin because: 1) it is possible to compare closely-related myelinated and non-myelinated forms; 2) nerve cells can be re-identified from one individual to the next, and 3) development of myelin can be tracked in identified cells through all developmental stages. In this project, physiological and computational approaches will be used in a comparative structure-function analysis of myelin in the two crustacean groups: the malacostraca and the calanoid copepods. Myelin has evolved independently in these two groups, yet it shares many features between the two, while being distinct in structure and origin. Some crustaceans transition from completely non-myelinated to fully myelinated nervous systems during development, and thus provide a good model in which to investigate nerve impulse conduction in incompletely formed myelin. Characterizing the commonalities in structure and function for myelin in copepods vs malacostracans will provide new insights into the function and evolution of vertebrate myelin. This study will start answering the question of how and why myelin evolved.The project will train young undergraduate scientists in interdisciplinary biology and team research, build diversity in science, technology, engineering and math; and provide public access to microscopic images for educational and data mining purposes. Postdoctoral trainees on the project will be educated in the preparation and examination of material for transmission electron microscopy, extracellular electrophysiological stimulation and recording techniques, and computational modeling of neuronal functioning.