Role of Skin Biomechanics in Mechanoreceptor Response

描述(申请人提供)：这个项目的最终目标是对人类触觉的起源和机制有一个科学的了解：灵长类指尖皮肤上凹陷、抚摸或振动的物体的形状、柔软度和表面纹理是如何由机械感受器群体编码的。对于这些刺激，人们试图定量地了解什么时空载荷施加在皮肤上，它们是如何通过皮肤传递的，以及每种类型的空间分布的机械感受器群体传递哪些机械信号。在之前的赠款期间，重点放在指尖的整体机械行为上，而在本提案中，重点放在单个指垫脊纹和凹槽的机械结构及其对迈斯纳小体和默克尔椎间盘位置的影响上。在使用机器人刺激器、成像系统和前一批赠款期间开发的计算模型所获得的理解的基础上，将采用新的技术和实验方法来解决这一问题。下面列出的所有实验都将在人体和猴子的指垫上进行。 该方案的具体目的是(1)使用光学相干断层摄影术、超声背向散射显微镜和视频显微镜获得指垫皮肤脊和槽的高分辨率解剖和应变图像，(2)使用定制开发的微型机电传感器阵列测量物体-指脊接触界面处的压力的空间分布，(3)使用高精度触觉刺激器获得指垫皮肤和脊阻抗数据，(4)使用来自实验的数据来进一步改进指垫的高分辨率3D计算模型并执行涉及与形状和软对象接触的有限元模拟，以及(5)利用生物力学和以前的神经生理学实验的结果，结合现实的计算机模型，加深对皮肤生物力学在机械感受器反应中的作用的理解。这项研究的好处包括从受体动力学中描述组织力学在外周神经反应中的作用，以及最终帮助区分外周和中枢机制在躯体感觉信息处理中的作用。从临床角度来看，长期受益的一个例子是能够设计更好的测试来评估正常和受损手的触觉敏感度，以帮助诊断、治疗和康复。另一个副产品应用的例子是，在上一次赠款期间开发的超声背向散射显微镜在活体皮肤损伤成像方面显示出了希望。

DESCRIPTION (provided by applicant): The ultimate goal of this project is to gain a scientific understanding of the origins and the mechanisms of human tactile sense: how shape, softness and surface texture of objects indented, stroked or vibrated on the primate fingertip skin are encoded by populations of mechanoreceptors. For these stimuli, a quantitative understanding of what spatio-temporal loads are imposed on the skin, how they are transmitted through the skin, and which mechanical signals are transduced by each type of spatially distributed mechanoreceptor populations is sought. Whereas the focus in the previous grant periods has been on the mechanical behavior of the fingertip as a whole, in this proposal the focus is on the mechanics of individual fingerpad ridges and grooves and its impact on Meissner corpuscle and Merkel disc locations. Building on the understanding gained with the use of robotic stimulators, imaging systems, and computational models developed over the previous grant period, new technologies and experimental methods will be brought to bear upon the problem. All the experiments listed below will be conducted on human and monkey fingerpads in vivo. The specific aims of this proposal are (1) to obtain high resolution anatomical and strain images of the fingerpad skin ridges and grooves using Optical Coherance Tomography, Ultrasound Backscatter Microscopy, and Video microscopy, (2) to measure the spatial distribution of pressure at the object-finger ridge contact interface using custom developed micro-electromechanical sensor arrays, (3) to obtain fingerpad skin and ridge impedance data using a high precision tactile stimulator, (4) to use the data from experiments to further improve high resolution 3D computational models of the fingerpad and perform finite element simulations involving contact with shaped and soft objects, and (5) to use the results from proposed biomechanical and previous neurophysiological experiments together with realistic computer models to develop a deeper understanding of the role of skin biomechanics in mechanoreceptor response. The benefits of this research include the delineation of the role of tissue mechanics from receptor dynamics in peripheral neural response, as well as eventually aiding the differentiation of the roles of peripheral and central mechanisms in somatosensory information processing. One example of a long-term benefit from a clinical standpoint will be the ability to design better tests for the evaluation of tactile sensibility of normal and impaired hands to aid diagnosis, treatment and rehabilitation. Another example of a spin-off application is that the Ultrasound Backscatter Microscope developed in the previous grant period has shown promise in imaging skin lesions in vivo.