Models of rodent facial musculature for the study of active tactile sensing

项目摘要： 啮齿类动物的触须系统是神经科学中最广泛使用的模型之一， 关于移动和触摸的信息被组合。在许多探索行为中，大鼠和小鼠 以一种被称为“拂动”的快速、有节奏的动作来回拂动它们的胡须，以积极地收集触觉 信息.虽然拂动是有节奏的，啮齿动物也可以改变他们的胡须如何移动取决于 所需的感官信息，以及它们的特定行为。研究人员几乎可以开始 在触须系统的运动和触摸之间“闭环”，除了一个关键的差距：我们不 还具有啮齿动物面部肌肉组织的三维（3D）模型。如果没有这样的模式， 确定大鼠如何改变其肌肉活动，以改变胡须运动，并获得特定类型的 感官信息我们无法知道哪种胡须运动是通过生物力学固定的， 老鼠可以主动控制的动作。我们不能完全理解发送给触须的运动指令 肌肉.这项建议的中心目标是开发啮齿动物面部的三维（3D）模型 闭合这个缝隙的肌肉组织我们将首先使用触觉轮廓术，组织学，MRI， CT扫描来量化啮齿动物面部肌肉和保持胡须的毛囊的解剖结构。使用此 解剖，然后我们将构建胡须肌肉和毛囊的3D生物力学模型，以模拟 所有胡须的运动。这些模型将在几个不同的补充软件中进行验证和测试 系统，然后被用来测试11个特定的预测，为特定的功能，每个胡须相关的 肌肉.最后，我们将整合啮齿动物面部肌肉的3D模型与现有的模型，描述 触须运动的感觉和触觉方面。这些结合肌肉感觉的模拟将被直接比较 活跃的动物行为。这项工作朝着关闭电机动作和电机之间的循环迈出了一步。 获得的感觉数据，并帮助解开生物力学和神经控制过程中的相对作用， 不同类型的搅拌。拟议的工作将为晶须神经通路的各级研究提供信息， 初级感觉神经元到感觉和运动皮质区，脑干区域参与控制 胡须的动作更一般地说，搅拌代表了一个独特的窗口，以了解意志控制如何能够 调节或覆盖中心模式的运动。节奏和非节奏的变化之间的过渡， 有节奏的运动对于嗅、呼吸、嗅觉、咀嚼 吞咽，吮吸，拟议的工作因此可以阐明一些神经力学基础， 儿童和老年吞咽困难。

Project Summary: The rodent vibrissal (whisker) system is one of the most widely-used models in neuroscience to study how information about movement and touch are combined. During many exploratory behaviors, rats and mice sweep their whiskers back and forth in a rapid, rhythmic motion called “whisking” to actively gather touch information. Although whisking is rhythmic, rodents can also change how their whiskers move depending on the desired sensory information, and on their particular behavior. Researchers are nearly able to begin to “close-the-loop” between movement and touch for the whisker system, except for one critical gap: we do not yet have a three dimensional (3D) model of rodent facial musculature. Without such a model, we cannot identify how the rat changes its muscle activity to change whisker motion and acquire particular types of sensory information. We cannot know which whisker motions are fixed via the biomechanics, versus which motions the rat can actively control. We cannot fully understand the motor commands sent to the whisker muscles. The central goal of this proposal is to develop three-dimensional (3D) models of rodent facial musculature that close this gap. We will first use a novel combination of tactile profilometry, histology, MRI, and CT-scans to quantify the anatomy of rodent facial muscles and the follicles that hold the whiskers. Using this anatomy, we will then construct 3D biomechanical models of the whisker muscles and follicles to simulate the motion of all whiskers. These models will be validated and tested in several different complementary software systems, and then be used to test eleven specific predictions for the particular function of each whisker-related muscle. Finally, we will integrate the 3D models of rodent facial muscles with existing models that describe the sensory, tactile side of whisker motion. These combined muscle-sensory simulations will be directly compared with active animal behavior. This work takes a step towards closing the loop between motor action and the sensory data acquired, and helps disentangle the relative roles of biomechanics and neural control during different types of whisking. The proposed work will inform all levels of study of whisker neural pathways, from primary sensory neurons to sensory and motor cortical areas, to brainstem regions involved in controlling whisker motions. More generally, whisking represents a unique window into how volitional control can modulate or override centrally-patterned movement. The transition between varieties of rhythmic and non- rhythmic movement has important implications for the coordination of sniffing, breathing, olfaction, chewing, swallowing, and suckling, and the proposed work could thus shed light on the neuromechanical basis for some pediatric and geriatric dysphagias.