Initiation of Mauthner- or Non-Mauthner-Mediated Fast Escape Evoked by Different Modes of Sensory Input
Initiation of Mauthner- or Non-Mauthner-Mediated Fast Escape Evoked by Different Modes of Sensory Input
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DOI：
10.1523/jneurosci.1435-08.2008
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发表时间：
2008-10-15
影响因子：
5.3
通讯作者：
Oda, Yoichi
中科院分区：
文献类型：
--
作者：
Kohashi, Tsunehiko;Oda, Yoichi
脑干网状脊髓神经元（rsn）是脊椎动物感觉运动整合的主要下行系统。斑马鱼配对的rsn之一，毛特纳(M)细胞，被认为是启动快速逃离突然的有害刺激。另外两个与m细胞形态同源的rsn也被认为在控制快速逃逸中起关键作用。然而，在快速逃逸过程中，m细胞及其同源物的活动与通过它们的激活引发逃逸的感觉输入之间的关系尚不清楚。对斑马鱼快速逃跑过程中后脑RSN活动与尾巴翻转运动同时进行了监测。对幼虫进行共聚焦钙成像，幼虫体表包埋在琼脂中，但允许其尾巴自由移动。将脉冲水射流应用于耳泡（OV）以激活前庭声输入，在同侧m细胞（m -逸出）中引发对侧快速尾翻转，其潜伏期短，Ca2+明显增加，反映了单一动作电位。水射流对头部皮肤进行触觉刺激可引起快速逃逸，但发生延迟且m细胞未放电（非m逃逸）。在消除m细胞或OV后，只启动非m逃逸。同时对m细胞及其同源物之一MiD3cm进行高速共聚焦成像，发现在快速逃逸过程中，MiD3cm的活性是互补的：在m逃逸过程中，MiD3cm的活性较低，而在非m逃逸过程中，MiD3cm的活性较高。这些结果表明，m细胞放电是由听觉前庭输入引起的短潜伏期快速逃逸的必要条件，而MiD3cm更多地参与由头-触觉输入驱动的非m -逃逸。
Brainstem reticulospinal neurons (RSNs) serve as the major descending system in vertebrate sensorimotor integration. One of the paired RSNs in zebrafish, the Mauthner (M) cell, is thought to initiate fast escape from sudden noxious stimuli. Two other paired RSNs, morphologically homologous to the M-cell, are also suggested to play key roles in controlling fast escape. However, the relationship among activities of the M-cell and its homologs during fast escape and the sensory inputs that elicit escape via their activation are unclear. We have monitored hindbrain RSN activity simultaneously with tail flip movement during fast escape in zebrafish. Confocal calcium imaging of RSNs was performed on larvae rostrally embedded in agar but with their tails allowed to move freely. Application of a pulsed waterjet to the otic vesicle (OV) to activate acousticovestibular input elicited contralateral fast tail flips with short latency and an apparent Ca2+ increase, reflecting a single action potential, in the ipsilateral M-cell (M-escape). Application of waterjet to head skin for tactile stimulation elicited fast escapes, but onset was delayed and the M-cell did not fire (non-M-escape). After eliminating either the M-cell or OV, only non-M-escape was initiated. Simultaneous high-speed confocal imaging of the M-cell and one of its homologs, MiD3cm, revealed complementary activation during fast escape: MiD3cm activity was low during M-escape but high during non-M-escape. These results suggest that M-cell firing is necessary for fast escape with short latency elicited by acousticovestibular input and that MiD3cm is more involved in non-M-escape driven by head-tactile input.