Collaborative Research: Sensory feedback loops in a swimming lamprey: Integrating fluid dynamics, body mechanics, and neurophysiology

合作研究：游泳七鳃鳗的感觉反馈回路：整合流体动力学、身体力学和神经生理学

• 批准号: 1312955
• 负责人: Lisa Fauci
• 金额: $ 15.46万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1312955&HistoricalAwards=false
• 关键词: Collaborative; Research; Sensory; feedback; loops

This project will develop multiscale mathematical models that integrate neurophysiology, muscle mechanics, and fluid dynamics that govern the swimming of lamprey, the most basal living vertebrate. The models will be used to develop and test general principles for how animals manage to move stably and effectively through complex and changing environments. The PIs have developed the first mathematical model of a swimming organism to fully couple a surrounding fluid with a simulated animal. In this project, the PIs will add simulated nervous and sensory systems, in order to test broad hypotheses for how animals must respond to perturbations for stable and effective swimming. The approach of the project is to consider how the dynamics of swimming emerges from the inherent coupling of all of these elements. The PIs hypothesize that sensory feedback is necessary to support the locomotor pattern as oscillation frequency increases, but, at a particular oscillation frequency, mechanical interactions alone can be sufficient to stabilize the swimmer against both neural noise and fluid perturbations. To test these hypotheses, the PIs combine two different classes of mathematical models: (1) a high-fidelity computational fluid dynamic (CFD) model based upon the incompressible Navier-Stokes equations to estimate the forces and the motion of the body; (2) coupled oscillator models to describe the neural circuit that generates the locomotor pattern, called a central pattern generator (CPG) and its sensory inputs. The CFD model simulates aspects of the system where the governing equations and parameters are known, while the CPG models allow us to examine general principles about sensorimotor feedback for aspects where fewer details are known.All animals interact with their environment using flexible structures such as hairs, antennae, fins, limbs, and even their entire bodies, and all of these structures deform in response to both internal body forces and external environmental forces. And all animals that move have nervous systems that use electrical signals to activate muscles to produce force and to respond to sensory inputs that result from those environmental interactions. To understand how animals move effectively in the physical world, one must understand the interactions of many different forces, including forces from passive tissue properties, active muscular forces, and forces from the external environment. Such an understanding is critical to the development of next generation prosthetic limbs that enable adaptive and effective motion in complex environments, and to the progress of therapies for spinal cord injury that rely on the coupling between the damaged spinal circuits, the mechanics of legs, and the interaction with the external world. In this project, the PIs will investigate how the coupling among these different systems and forces contributes to the dynamics and stability of motion in a model swimming organism.

这个项目将开发多尺度的数学模型，将神经生理学、肌肉力学和流体动力学结合在一起，管理七鳃鳗的游泳行为，七鳃鳗是最基本的脊椎动物。这些模型将被用来开发和测试动物如何在复杂多变的环境中稳定有效地移动的一般原理。PI开发了第一个游泳有机体的数学模型，将周围的流体与模拟动物完全耦合。在这个项目中，PI将增加模拟的神经和感觉系统，以测试动物必须如何应对干扰才能稳定和有效地游泳的广泛假设。该项目的方法是考虑游泳的动力是如何从所有这些元素的内在耦合中出现的。PI假设，随着振荡频率的增加，感觉反馈对于支持运动模式是必要的，但在特定的振荡频率下，仅机械相互作用就足以稳定游泳者免受神经噪音和流体干扰。为了检验这些假设，PI结合了两类不同的数学模型：(1)基于不可压缩的Navier-Stokes方程的高保真计算流体动力学(CFD)模型，用于估计物体的力和运动；(2)耦合振荡器模型，用于描述产生运动模式的神经电路，称为中央模式生成器(CPG)及其感觉输入。CFD模型模拟系统的某些方面，其中控制方程和参数是已知的，而CPG模型允许我们检查有关感知运动反馈的一般原理，而这些方面的细节较少。所有动物都使用灵活的结构与环境交互，如毛发、天线、鳍、四肢，甚至整个身体，所有这些结构都会随着体力和外部环境力的作用而变形。所有移动的动物都有神经系统，这些神经系统使用电信号来激活肌肉，产生力量，并对环境相互作用产生的感觉输入做出反应。为了了解动物如何在物理世界中有效地运动，我们必须了解许多不同力的相互作用，包括来自被动组织特性的力、主动肌肉力和来自外部环境的力。这种理解对于下一代假肢的发展至关重要，这种假肢能够在复杂的环境中实现自适应和有效的运动，对于依赖于受损脊髓回路之间的耦合、腿的力学以及与外部世界的相互作用的脊髓损伤治疗的进展来说，这种理解是至关重要的。在这个项目中，PI将研究这些不同系统和力之间的耦合如何有助于在一个模型游泳有机体中运动的动力学和稳定性。