Testing the roles of motoneuron membrane currents for behaviorally adequate motor output by targeted genetic manipulations of an identified flight motoneuron in Drosophila

从中枢神经回路产生模式化输出取决于单个神经元的突触连接性和固有膜特性。运动神经元是中枢模式产生回路和肌肉之间的中继站。运动神经元不仅仅是网络输入的追随者，它们的内在属性塑造了最终的运动输出。本计画将利用果蝇的遗传学工具，来解开一个已确认的运动神经元的突触输入整合与放电输出的离子机制。运动神经元的离子电流束将通过原位膜片钳分析来描述。药理学和有针对性的基因操作将被用来破译哪些基因是每一个电流的基础（目标1）。第二，突触输入整合和树突状细胞钙信号将在原位钙成像实验分析（目标2）。这些数据将作为基石，以确定特定的离子通道的作用，塑造运动神经元输出相结合的有针对性的遗传操作在选定的运动神经元与细胞外记录在完整的行为动物（目标3）。最后，调制生物胺是已知的调整运动模式，以改变要求。本计画将测试生物胺是否直接调节运动神经元离子通道，以及其功能后果为何（目标4）。离子通道的高度保守性使得脊椎动物运动神经元可能具有类似的功能。了解正常的运动神经元功能是解决疾病期间或脊髓损伤后功能障碍的先决条件。

The generation of patterned output from central neural circuits depends on synaptic connectivity and intrinsic membrane properties of the individual neurons. Motoneurons are the relays station between central pattern generating circuitry and muscles. Motoneurons are not mere followers of network input, but their intrinsic properties shape the final motor output. This project will use genetic tools available in Drosophila to unravel the ionic mechanisms underlying synaptic input integration and firing output of an identified motoneuron. The motoneuron’s ionic current bouquet will be described by in situ patch clamp analysis. Pharmacological and targeted genetic manipulations will be used to decipher which genes underlie each current (objective 1). Second, synaptic input integration and dendritic calcium signaling will be analyzed by in situ calcium imaging experiments (objective 2). These data will serve as bedrock to determine the roles of specific ion channels for shaping motoneuron output by combining targeted genetic manipulations in selected motoneurons with extracellular recordings in intact behaving animals (objective 3). Finally, modulation by biogenic amines is known to adjust motor patterns to changing requirements. This project will test whether biogenic amines directly modulate motoneuron ion channels and what the functional consequences are (objective 4). The highly conserved nature of ion channels makes similar functions in vertebrate motoneurons likely. Understanding normal motoneuron function is a prerequisite for addressing malfunction during diseases or after spinal cord injury.