SKIN BIOMECHANICS AND MECHANORECEPTOR RESPONSE

该项目的主要目标仍然是调查 灵长类动物指尖的生物力学与 触觉感知期间皮肤机械感受器的反应。在 在过去的五年里，计算方法在 灵长类指尖理想模型的机械分析， 有助于更深入地理解接触的机制 在皮肤和不同形状的物体之间， 通过皮肤的机械信号， 通过皮肤机械感受器的神经冲动。具体目标是 建议是（l）逐步完善模型，使它们密切 近似灵长类动物的几何和材料特性 指垫，（2）扩大被按压或 描边的模型，包括更多的形状，软对象， 显微纹理，（3）进行一系列的生物力学实验 在体内条件下使用多种技术 视频显微镜，磁共振成像（MRI）和计算机- 受控的机械刺激器模型的顺序将是 通过将他们的预测与适当的预测进行比较， 生物力学和神经生理学实验的数据。 这些调查的出发点是三维的 已经开发的同质模型， 猴和人指尖外部几何形状的测量 使用视频显微镜系统。用于线性和非线性测量的必要软件 均匀和非均匀非线性有限元分析 模型，以及各种计算机平台的使用 （包括麻省理工学院的超级计算机）的大量计算 已经过测试和验证。模型细化的主要阶段 包括结合基于MRI的真实内部几何结构， 非均匀模型，指垫的粘弹性行为的基础上， 实验使用视频显微镜，连同几何和机械 基于精细生物力学实验的乳头嵴行为 用高精度刺激器这些实验旨在帮助 模型的开发，并与以前获得的 生物力学和神经生理学数据，将严格地 验证指垫和换能机构的模型。长 长期的好处，这样一个定量的了解的起源和 触觉信息的机制将包括开发良好的 用于评定触觉以帮助康复的试验 和触觉交流的设计 为视力受损者和失聪者提供的辅助器具。

The primary goal of this project continues to be the investigation of the relationship between the biomechanics of the primate fingertip and responses of cutaneous mechanoreceptors during tactile sensing. In the past five years, the application of computational methods to the mechanistic analysis of idealized models of the primate fingertip has contributed to a deeper understanding of the mechanics of contact between the skin and objects of differing shapes, the transmission of the mechanical signals through the skin, and their transduction into neural impulses by cutaneous mechanoreceptors. The specific aims of this proposal are (l) to gradually refine the models so that they closely approximate the geometrical and material properties of the primate fingerpad, (2) to expand the variety of stimuli that are pressed or stroked on the models to include more shapes, soft objects and microtextures, and (3) to perform a series of biomechanical experiments under in vivo conditions using a variety of techniques including the use of videomicroscopy, Magnetic Resonance Imaging (MRI) and computer- controlled mechanical stimulators. The sequence of models will be verified at each stage by comparing their predictions with appropriate data from biomechanical and neurophysiological experiments. Starting points for these investigations are the three dimensional homogeneous models that have already been developed using empirical measurements of the external geometry of monkey and human fingertips using a videomicroscopy system. The necessary software for linear and nonlinear finite element analyses of homogeneous and nonhomogeneous models, as well as the usage of the various computer platforms (including the MIT supercomputer) for the large number of computations have been tested and verified. The major stages of model refinement consist of incorporation of realistic internal geometry based on MRI for nonhomogeneous models, viscoelastic behavior of the fingerpad based on experiments using videomicroscopy, together with geometry and mechanical behavior of papillary ridges based on fine biomechanical experiments with a high precision stimulator. The experiments are designed to help the model development, and together with the previously obtained biomechanical and neurophysiological data, will serve to rigorously verify the models of the fingerpads and transduction mechanisms. Long term benefits of such a quantitative understanding of the origins and mechanisms of tactile information would include the development of good tests for the evaluation of tactile sensibility to aid in rehabilitation of hand-impaired individuals and the design of tactile communication aids for visually impaired and deaf individuals.