Neuromechanical Resonance and Distributed Control in Organismal Pumping

对于许多游泳和飞行的动物来说，运动是通过将动量从有机体的身体或附属物转移到当地的流体环境中而出现的。这种运动是内部神经机械过程的结果，该过程将神经信号转化为肌肉组织的激活。随着组织工程泵和生物混合机器人随着每一项技术的进步而进步，发展它们的可激发材料的激励背后的理论是至关重要的。虽然生物体生物力学和仿生材料的大部分理论都在机械共振的背景下研究了它们的性能，但很少有人研究可兴奋材料的内部激励。神经时标、肌肉激活信号和机械时标之间的相互作用，是结构的弹性轮廓所固有的，已被发现在受激励材料的最终运动中起着重要作用。此外，了解起搏器在驱动神经信号中所扮演的角色，可以解释健壮性如何根植于可兴奋的系统中。这项研究计划将开发和使用一套描述神经机械激活和起搏器过程的数学模型，并将“活的”材料纳入计算流体-结构相互作用模型。这里开发的数学原理适用于其他生物泵和具有可激发材料的系统的执行器的设计。该项目将涉及与研究生和本科生的合作。这项研究计划的重点将是研究神经机械驱动波速和材料波速之间相互作用的数学理论，以及研究起搏器过程在驱动这些神经机械系统中所起的作用。为了研究这种相互作用，选择了月亮水母作为模式生物，因为它们的神经系统和肌肉形态相对简单。为了开发这一框架，研究人员将使用三种不同的数学模型：(1)考虑内部激励的一维/二维弹性波动方程模型；(2)描述导致激励的神经生理活动的耦合神经网络模型；(3)描述水母钟的力和运动的三维计算流固相互作用(FSI)模型。该研究计划的重点是激励波速、起搏器过程和流体环境在生物泵和可兴奋材料的性能中所起的作用。所产生的框架将用于开发第一个游泳有机体的3-D模型，该模型将周围的液体与动物的紧急运动学完全耦合，该动物的紧急运动学是神经肌肉激活、弹性特性和起搏器过程的结果。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

For many swimming and flying animals, locomotion emerges from the transfer of momentum from an organism's body or appendage to the local fluid environment. This motion is a result of internal neuromechanical processes that translate neural signals into the activation of muscular tissue. As tissue-engineered pumps and biohybrid robotics improve with every technological advancement, developing the theory behind the actuation of their excitable materials is paramount. While much of the theory in organismal biomechanics and biomimetic materials has examined their performance in the context of mechanical resonance, very little work has been done examining the internal actuation of excitable materials. The interplay between neural time scales, that signal for muscular activation, and mechanical time scales, that are inherent to the elastic profile of the structure, have been found to play an important role in the resulting motion of an actuated material. Furthermore, understanding the role pacemakers play in driving the neural signaling can elucidate how robustness can be ingrained into excitable systems. This research program will develop and employ a suite of mathematical models that describe neuromechanical activation and pacemaker processes, as well as incorporate “living” materials into computational fluid-structure interaction models. The mathematical principles developed here are relevant in the design of actuators for other biological pumps and systems with excitable materials. The project will involve work with both graduate and undergraduate students. The focus of this research program will be to both examine the mathematical theory that girds the interplay between the neuromechanical actuation wave speed and the material wave speed, as well as examine the role pacemaker processes play in driving these neuromechanical systems. To examine this interplay, a moon jellyfish is chosen as a model organism due to the relative simplicity of their nervous system and muscle morphology. To develop this framework the investigators will employ three different classes of mathematical models: (1) 1-D/2-D elastic wave equation model with internal actuation; (2) a coupled neuronal network model to describe the neurophysiological activity that leads to actuation; (3) a 3-D computational fluid-structure interaction (FSI) model to describe the forces and motion of a jellyfish bell. The research program's focus is on the roles of actuation wave speeds, pacemaker processes, and the fluid environment plays in the performance of organismal pumps and excitable materials. The resulting framework will be used to develop the first 3-D model of a swimming organism that fully couples the surrounding fluid with an animal whose emergent kinematics are a consequence of neuromuscular activation, elastic properties, and pacemaker processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.