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: 1312987
• 负责人: Eric Tytell
• 金额: $ 5.3万
• 依托单位: Tufts 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 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1312987&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.

本计画将发展多尺度数学模型，整合神经生理学、肌肉力学与流体力学，以控制七鳃鳗这种最基本的脊椎动物的游动。这些模型将用于开发和测试动物如何在复杂和不断变化的环境中稳定有效地移动的一般原则。PI开发了第一个游泳生物体的数学模型，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的广泛假设。该项目的方法是考虑如何从所有这些元素的内在耦合中产生游泳的动力学。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，但是，在特定的振荡频率下，单独的机械相互作用足以稳定游泳者对抗神经噪声和流体扰动。为了验证这些假设，PI结合了联合收割机两种不同类型的数学模型：（1）基于不可压缩Navier-Stokes方程的高保真计算流体动力学（CFD）模型，用于估计身体的力和运动;（2）耦合振荡器模型，用于描述产生运动模式的神经回路，称为中央模式发生器（CPG）及其感觉输入。计算流体力学模型模拟的是已知控制方程和参数的系统，而CPG模型则允许我们在已知细节较少的情况下研究感觉运动反馈的一般原理。所有动物都使用灵活的结构与环境互动，如毛发、触角、鳍、四肢，甚至整个身体，并且所有这些结构都响应于内部体力和外部环境力而变形。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，并对来自这些环境相互作用的感官输入做出反应。要了解动物如何在物理世界中有效地移动，必须了解许多不同力量的相互作用，包括被动组织特性的力量，主动肌肉力量和外部环境的力量。这样的理解是至关重要的下一代假肢的发展，使适应性和有效的运动在复杂的环境中，和脊髓损伤的治疗方法的进展，依赖于受损的脊髓回路之间的耦合，腿的力学，和与外部世界的相互作用。在这个项目中，PI将研究这些不同的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力学和稳定性。