Functional organization of morphologically homologous neurons repeated in the adjacent segments of vertebrate hindbrain

脊椎动物后脑相邻节段重复的形态同源神经元的功能组织

基本信息

批准号：
18300134
负责人：
ODA Yoichi
金额：
$ 9.91万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Vertebrate hindbrains are segmented structure. Seven clusters of reticulospinal neurons (RSNs) are periodically arranged along the neuraxis in the hindbrain of zebrafish and goldfish. RSNs sharing a common morphology in adjacent segments are referred to as segmental homologs. In the present study we have investigated the functional organization of a series of segmental homologs, Mauthner (M) cells in the fourth segment (r4) and its homologs in r5 and r6, by examining their activities during escape behavior and mutual connections between them. Confocal calcium imaging of zebrafish RSNs during fast escape behavior in response to water pulse stimulus to head revealed that M-cell initiates acoustically evoked fast escape and its homologs are more involved in tactile evoked escape. M-cell and the homologs show complementary activation during fast escape. The activity relationship is supported by inhibitory connection mediated by inhibitory interneurons from M-cell to the homologs demonstrat … More ed by paired recording of them in goldfish. Acoustically evoked escape behavior appears later than tactile induced escape. We investigated mechanisms underlying acquisition of auditory responsiveness of M cell. Whole-cell recordings from M-cells, exracellular recording of inner ear hair cell (HC) activity and morphological investigations of the auditory afferents from HC to M cells in zebrafish embryos and larvae suggested that functional maturation of inner ear HCs after formation of the auditory afferent circuits is a critical process in the acquisition of auditory inputs by M-cell. Interestingly after acquisition of auditory responsiveness, the M-cell changes their firing pattern in response to stepwise depolarization, from burst as other RSNs exhibit to typical single firing of matured M-cell. Together, the functional differentiation elicited by acquisition of specific sensory input and the interconnection among the homologs may underlie functional organization of segmental homologs to produce adaptive escape behaviors during various environments. Less

脊椎动物后脑是分段结构。七个网状神经元（RSN）的七个簇在斑马鱼和金鱼的后脑中定期排列。在相邻段中共享共同形态的RSN称为分段同源物。在本研究中，我们通过检查了R5和R6中的第四部分（R4）中的Mauthner（M）细胞的一系列分段同源物（M）细胞的功能组织，通过检查其在逃生行为和它们之间的相互连接期间的活性。在快速逃生行为中，斑马鱼RSN的共聚焦钙成像响应水脉冲刺激，表明M细胞引起了声学诱发的快速逃生，其同源物更参与触觉引起的逃生。 M-Cell和同源物在快速逃生过程中显示出完全激活。活性关系得到了抑制性连接的支持，该抑制性连接是由M-Cell到同源物的抑制性中间神经元介导的……通过在Goldfish中对它们的配对记录，更多的是。声学诱发的逃生行为似乎晚于触觉引起的逃生。我们研究了M细胞听觉响应能力的获得的基础机制。来自M细胞的全细胞记录，内耳毛细胞（HC）活性的等应有记录以及对斑马鱼胚胎中HC到M细胞的听觉传入和幼虫的形态学研究表明，在获得听觉的过程中，在获得听觉的过程中，内耳的功能性成熟是在获得听觉过程中的关键过程。有趣的是，在获得听觉响应能力后，M细胞会因逐步去极化而改变其发射模式，因为其他RSN暴露于典型的成熟M-Cell的单一射击。总之，通过获取特定的感觉输入和同源物之间的互连引起的功能分化可能是分段同源物的功能组织，以在各种环境中产生适应性的逃生行为。较少的