A subset of interneurons required for Drosophila larval locomotion.
A subset of interneurons required for Drosophila larval locomotion.
复制标题
DOI：
10.1016/j.mcn.2015.11.008
复制
发表时间：
2016-01
期刊：
影响因子：
--
通讯作者：
Thomas JB
中科院分区：
文献类型：
--
作者：
Yoshikawa S;Long H;Thomas JB
定义产生运动行为的神经回路的努力已经使人们对脊髓内的一些组成部分有了初步的了解，并对几种无脊椎动物的运动模式发生器有了基本的了解。然而，人们对这些电路在开发过程中如何组装知之甚少。我们正在定义遗传易驯化的果蝇果蝇中产生幼虫运动的神经回路，以研究运动回路的发育。幼虫的向前运动涉及体壁肌肉收缩的定型从后到前的节段易位，是由相对少量的已识别肌肉、运动和感觉神经元以及第一龄幼虫每节约 270 个双边配对中间神经元的未知数量产生的。为了开始识别相关的中间神经元，我们有条件地灭活了中间神经元子集的突触传递，并分析了对运动的影响。从这个屏幕中，我们确定了每个半节段 25 个中间神经元的子集，称为侧向运动神经元 (LLN)，它们是运动所需的。 LLN 的失活和组成性激活都会扰乱运动，表明需要 LLN 的模式化输出。通过在 LLN 中表达钙指示剂，我们发现它们在 CNS 内显示出与肌肉收缩波的节段易位相对应的从后到前的活动波。 LLN 的识别代表了阐明产生幼虫运动的电路的第一步。
Efforts to define the neural circuits generating locomotor behavior have produced an initial understanding of some of the components within the spinal cord, as well as a basic understanding of several invertebrate motor pattern generators. However, how these circuits are assembled during development is poorly understood. We are defining the neural circuit that generates larval locomotion in the genetically tractable fruit fly Drosophila melanogaster to study locomotor circuit development. Forward larval locomotion involves a stereotyped posterior-to-anterior segmental translocation of body wall muscle contraction and is generated by a relatively small number of identified muscles, motor and sensory neurons, plus an unknown number of the ~270 bilaterally-paired interneurons per segment of the 1st instar larva. To begin identifying the relevant interneurons, we have conditionally inactivated synaptic transmission of interneuron subsets and assayed for the effects on locomotion. From this screen we have identified a subset of 25 interneurons per hemisegment, called the lateral locomotor neurons (LLNs), that are required for locomotion. Both inactivation and constitutive activation of the LLNs disrupt locomotion, indicating that patterned output of the LLNs is required. By expressing a calcium indicator in the LLNs, we found that they display a posterior-to-anterior wave of activity within the CNS corresponding to the segmental translocation of the muscle contraction wave. Identification of the LLNs represents the first step toward elucidating the circuit generating larval locomotion.