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

项目总结： 啮齿动物的触觉(胡须)系统是神经科学中最广泛使用的模型之一，用来研究 有关移动和触摸的信息被结合在一起。在许多探索行为中，大鼠和小鼠 以一种快速、有节奏的动作来回扫除它们的胡须，这种动作被称为“搅拌”，以积极地聚集触觉 信息。尽管搅拌是有节奏的，啮齿类动物也可以改变它们的胡须移动的方式，这取决于 所需的感官信息，以及它们的特定行为。研究人员几乎能够开始 对于胡须系统来说，移动和触摸之间的“闭合环路”，除了一个关键的缺口：我们不 但有一个啮齿动物面部肌肉的三维(3D)模型。没有这样的模式，我们就不能 确定大鼠如何改变其肌肉活动以改变胡须的运动并获得特定类型的 感官信息。我们无法知道哪些胡须运动是通过生物力学固定的，而哪些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胡须的马达命令 肌肉。这项提议的中心目标是开发啮齿动物面部的三维(3D)模型 缩小这一差距的肌肉组织。我们将首先使用触觉轮廓术、组织学、核磁共振和 CT扫描可以量化啮齿动物面部肌肉和支撑胡须的毛囊的解剖结构。使用这个 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，每个胡须相关的特定功能 肌肉。最后，我们将把啮齿动物面部肌肉的3D模型与现有的描述 胡须运动的感官、触觉方面。这些组合的肌肉-感觉模拟将直接进行比较 有活跃的动物行为。这项工作向闭合电机动作和 获得的感觉数据，并帮助解开生物力学和神经控制在 不同类型的搅拌。拟议的工作将为各级胡须神经通路的研究提供信息，从 初级感觉神经元到感觉和运动皮质区域，到参与控制的脑干区域 胡须运动。更广泛地说，搅动代表了一扇独特的窗口，让我们了解意志控制如何 调整或覆盖中心图案的移动。节奏变化与非节奏变化之间的转换 有节奏的运动对协调嗅觉、呼吸、嗅觉、咀嚼、 吞咽和哺乳，这项拟议的工作因此可以揭示一些人的神经力学基础 儿童和老年性吞咽困难。

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.