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.

该项目将开发多尺度数学模型，以整合神经生理学，肌肉力学和流体动力学，这些动力学控制着最基础的脊椎动物lampre鼠游泳。这些模型将用于制定和测试一般原则，以通过动物如何通过复杂和不断变化的环境稳定有效地移动。 PI开发了游泳有机体的第一个数学模型，将周围的流体与模拟动物完全融合在一起。 在该项目中，PI将添加模拟的神经和感觉系统，以测试动物必须如何应对稳定和有效游泳的扰动。该项目的方法是考虑一下游泳动态如何从所有这些元素的固有耦合中产生。 PI假设有感觉反馈是随着振荡频率的增加而支撑运动模式的必要条件，但是在特定的振荡频率下，仅机械相互作用就足以使游泳者稳定在神经噪声和流体扰动上。为了检验这些假设，PIS结合了两个不同类别的数学模型：（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，以估算人体的力和运动； （2）耦合振荡器模型来描述生成运动模式的神经电路，称为中央模式发生器（CPG）及其感觉输入。 CFD模型模拟了系统的方程式和参数的模拟各个方面，而CPG模型使我们能够检查有关较少细节的方面的一般原则，以了解较少的细节。所有动物都使用柔性结构（例如毛发）与环境进行交互，天线，鳍，四肢，甚至它们的整个身体，所有这些结构都响应内部力量和外部环境力而变形。所有移动的动物都有神经系统，使用电信号激活肌肉以产生力并响应这些环境相互作用所产生的感觉输入。为了了解动物在物理世界中的有效运动，必须了解许多不同力量的相互作用，包括无源组织特性的力，主动肌肉力量和外部环境的力量。这种理解对于在复杂环境中能够自适应和有效运动的下一代假肢的发展以及脊髓损伤疗法的进展至关重与外部世界的互动。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模型游泳生物体运动的动态和稳定性。