Exploring the ties between neuronal migration and functional development

描述(申请人提供)：在拟议的研究中，我将建立与发育中的神经元和回路的结构、功能和迁移有关的基本原则。在发育过程中，神经元迁移发生在整个中枢神经系统，异常迁移导致多种神经疾病，包括共济失调、癫痫、精神分裂症和癫痫。通过在斑马鱼幼体模型中应用最先进的技术和可用的资源的独特组合，我希望通过研究正常和异常迁移对后脑面部分支运动神经元(FBMN)发育的影响，阐明迁移在回路形成中的复杂作用。这些神经元经历了早期的、戏剧性的尾部迁移，这可能起到重要的功能作用，使FBMN更接近尾部后脑的呼吸反射回路。其他研究迁移机制的实验室已经产生了各种各样的斑马鱼突变体，这些突变体专门扰乱了FBMN的尾部迁移，而不会对动物的一般健康造成不利影响。这些情况提供了一个独特的机会，可以在迁移和功能发育之间的复杂关系中站稳脚跟，对我们理解神经元迁移障碍具有重要的后果。在目标1中，我将通过研究斑马鱼幼体迁移后FBMN的功能和形态特性来定义功能发育的正常终点。我将使用贴片记录来量化FBMN的内在生理和节律反应特性，这可能支持这些细胞在呼吸行为中的作用。我还将可视化它们齿状茎的位置和范围，反映这些神经元接受突触输入的大脑区域。试点数据表明，这种方法将在描述重要的迁徙后FBMN特征方面卓有成效，为探索这些特征何时与迁徙有关而发展以及当迁徙中断时它们如何变化提供了基础。在目标2中，我将探索斑马鱼胚胎迁移过程中FBMN结构和功能特性的发展，以将功能发育的进展与迁移过程联系起来。我将结合传统的细胞内记录和钙成像(使用最近试行的转基因表达指示器)来追踪在Aim 1中发现的重要结构和功能标志的外观，以确定哪些性状在尾部迁移完成之前无法发育。在目标3中，我将确定突变斑马鱼幼体尾部迁移中断如何影响FBMN的结构和功能特性。使用目标1的方法，结合在目标2中获得的知识，我将寻找正常尾部迁移和异常尾部迁移的FBMN结构和功能差异的模式，以揭示神经系统补偿异常迁移的能力(或缺乏能力)。

DESCRIPTION (provided by applicant): In the proposed study, I will establish fundamental principles relating structure, function, and migration in developing neurons and circuits. Neuronal migration occurs throughout the central nervous system during development, and abnormal migration contributes to a wide variety of neurological disorders, including ataxia, seizures, schizophrenia, and epilepsy. By applying a unique combination of state-of-the-art techniques and available resources in the larval zebrafish model, I hope to shed light on the complex roles of migration in circuit formation, by studying the effect of normal and abnormal migration on the development of facial branchiomotor neurons (FBMNs) in the hindbrain. These neurons undergo an early, dramatic caudal migration that is likely to serve an important functional role, bringing FBMNs closer to respiratory reflex circuits in the caudal hindbrain. Othe laboratories studying the mechanisms of migration have generated a wide variety of zebrafish mutants that specifically disrupt caudal FBMN migration without adversely affecting the general health of the animal. These circumstances present a unique opportunity to gain a foothold in the complex relationship between migration and functional development, with important consequences for our understanding of neuronal migration disorders. In Aim 1, I will define the normal endpoint of functional development by studying the functional and morphological properties of postmigratory FBMNs in larval zebrafish. I will use patch recording to quantify intrinsic physiological and rhythmic response properties of FBMNs, which likely support the role of these cells in respiratory behavior. I will also visualize the location and extent of their denditic arbors, reflecting the brain region where these neurons receive synaptic inputs. Pilot data indicates that this approach will be fruitful in describing important postmigratory FBMN traits to provide the foundation for explorations of when these properties develop with respect to migration and how they change when migration is disrupted. In Aim 2, I will explore the development of FBMN structural and functional properties during migration in zebrafish embryos to relate the progress of functional development with the migratory process. I will combine traditional intracellular recordings with calcium imaging (using a recently piloted transgenically expressed indicator) to trace the appearance of important structural and functional landmarks found in Aim 1 in order to determine which traits fail to develop until caudal migration is complete. In Aim 3, I will determine how the structural and functional properties of FBMNs are affected by disruptions to caudal migration in mutant zebrafish larvae. Using the methods of Aim 1 and armed with the knowledge gained in Aim 2, I will look for patterns in structural and functional differences between FBMNs with normal and abnormal caudal migration, to reveal the capacity (or lack thereof) of the nervous system to compensate for abnormal migration.