CAREER: Vibration and Texture Perception

当我们的手指滑过一个纹理细密的表面时，皮肤会产生微小而复杂的振动，嵌入皮肤的特殊受体使我们能够感受到这些振动。不同的表面会引起不同的振动，正是基于这些差异，我们才能够区分丝绸和缎子。从皮肤振动中提取有意义信息的能力意味着尚未发现的神经机制。本计画探讨从纹理诱发振动中撷取表面纹理资讯的机制。为此，主要研究者记录（使用激光多普勒振动计）日常纹理表面引起的皮肤振动，并检查传达的信息。然后，他记录了恒河猴神经中各种纹理表面引起的反应，并让人类参与者使用这些相同的纹理进行辨别实验。利用人类和恒河猴感觉系统之间有据可查的同源性，他使用各种计算和机器学习技术来揭示神经反应的哪些方面解释了我们区分纹理的能力。最终，皮肤振荡的处理构成了一个独特的和知之甚少的体感处理模式。事实上，虽然在形状和运动的视觉和触觉处理之间已经画出了类比，但第二种处理模式与听觉系统有很强的类比。在这两个系统中，刺激信息是从频谱复杂的振荡（鼓膜或皮肤的听觉和触觉，分别）提取。除了重要的科学意义外，该项目的结果还将为传感上肢神经假体和虚拟触觉显示器的开发提供信息。最后，该项目包括一个重要的教育和外联部分，重点是本科教育、征聘代表性不足的群体以及向公众进行外联。

When we run our fingers across a finely textured surface, small, complex vibrations are elicited in the skin, and specialized receptors embedded in the skin allow us to sense these vibrations. Different surfaces elicit different vibrations, and it is on the basis of these differences that we are able to discriminate silk from, say, satin. The ability to extract meaningful information from skin vibrations implies neural mechanisms that have yet to be discovered. This project investigates the mechanisms by which information about surface texture is extracted from texture-elicited vibrations. To this end, the Principal Investigator records (using a laser Doppler vibrometer) the skin vibrations elicited by everyday textured surfaces and examines the information conveyed. He then records the responses evoked by various textured surfaces in the nerve of Rhesus macaques and has human participants perform discrimination experiments using these same textures. Exploiting the well-documented homology between human and Rhesus sensory systems, he uses a variety of computational and machine learning techniques to reveal which aspects of the neural response account for our ability to distinguish between textures. Ultimately, the processing of skin oscillations constitutes a distinct and poorly understood mode of somatosensory processing. Indeed, while analogies have been drawn between visual and tactile processing of shape and motion, this second processing mode draws strong analogies with the auditory system. In both systems, stimulus information is extracted from spectrally complex oscillations (of the ear drum or the skin for audition and touch, respectively). In addition to their important scientific implications, results from this project will inform the development of sensorized upper-limb neuroprostheses and of virtual haptics displays. Finally, the project comprises an important educational and outreach component, with a strong emphasis on undergraduate education, recruitment of under-represented groups, and outreach to the general public.