CRCNS US-German Research Proposal: Central Pattern Generators and Reflexive Feedback in Insect Locomotion: A Cross-Species Study

动物运动始于中枢神经系统，并导致可量化的机械活动；因此，它为神经计算提供了一个很好的窗口，神经计算产生有意的行为并对环境条件做出反应。运动起源于中枢模式生成器：脊椎动物脊柱和昆虫胸椎神经节中的神经网络产生有节奏的运动。一些制剂（如七鳃鳗、小龙虾）可以单独产生稳定的、接近周期性的节奏，其他制剂要么需要感官反馈来产生功能性步态，要么通过感官反馈来显着稳定。蟑螂和竹节虫就是这两种极端的例子。它们有着相同的基本神经和生物力学结构，但前者在粗糙的地面上奔跑迅速，而后者则适应在不同方向的树枝和树叶上缓慢行走。利用现有信息和收集新数据，该项目将比较这些物种并解决以下问题：(1)前馈运动协调的功能组织是什么：驱动单个腿和关节的神经回路如何耦合以实现肢体间协调？(2)感觉输入在协调中的作用：反馈如何影响运动模式，运动如何调节传入的感觉信息？(3)模式生成器和感觉反馈系统是如何调节的，以便在动物改变速度、面对意想不到的扰动和通过复杂地形时产生适当的动作？综合数学和计算模型的发展是回答这些问题的核心。新的数据将改进现有的模型，新的模型将跨越从竹节虫到蟑螂的形态和行为范围，使我们能够阐明它们对不同环境的适应策略。这项研究将加深我们对运动的产生和控制的理解，与动物和人类普遍相关。该项目的美国部分由数学科学部的数学生物学项目和综合有机体系统部的神经系统集群共同资助。德语部分由德国教育和研究部（BMBF）资助。

Animal locomotion begins in the central nervous system and results in quantifiable mechanical activity; it therefore provides an excellent window into the neural computations that create intentional behaviors and respond to environmental conditions. Locomotion originates in central pattern generators: neural networks in the spines of vertebrates and thoracic ganglia of insects that produce rhythmic movements. Some preparations (e.g. lamprey, crayfish) can produce stable, near-periodic rhythms in isolation, others either require sensory feedback to produce functional gaits or are significantly stabilized by it. Cockroaches and stick insects exemplify these two extremes. They share the same basic neural and biomechanical architecture, but the former run rapidly over rough ground, while the latter are adapted for slow walking on twigs and leaves with varied orientations to gravity. Using existing information and collecting new data, this project will compare these species and address questions such as:(1) What is the functional organization of feedforward motor coordination: How are neural circuits that drive individual legs and joints coupled to achieve inter-limb coordination?(2) What is the role of sensory input in coordination: How does feedback affect motor patterns, and how does locomotion modulate incoming sensory information?(3) How are pattern generators and sensory feedback systems modulated to create appropriate actions as animals change speed, face unexpected perturbations, and maneuver to negotiate complex terrain?The development of integrated mathematical and computational models is central to answering such questions. New data will improve existing models, and new models will be created to span the morphological and behavioral ranges from stick insects to cockroaches, allowing us to illuminate their adaptive strategies to different environments. This research will deepen our understanding of the generation and control of locomotion, with general relevance to animals and humans.The US component of this project is jointly funded by the Mathematical Biology program in the Division of Mathematical Sciences and the Neural Systems Cluster in the Division of Integrative Organismal Systems. The German component is funded by the German Ministry of Education and Research (BMBF).