Collaborative Research: Sensorimotor control of hand-object interactions

人们如何用手与物体互动是最复杂和最不为人所知的感觉运动技能之一。例如，当人们多次拿起同一个物体时，他们会使用不同的指尖力量来补偿指尖位置的差异。这种补偿是很重要的，因为它允许人们熟练地操作一个对象，而不必总是在相同的点上抓住它。几个重要的问题仍然存在：在指尖力量和位置的补偿性调节中，个体感觉模式（如触觉和视觉）的相对贡献是什么？指尖的力和位置是由中枢神经系统分别表示的吗？将它们推广到不同肢体或任务的机制是什么？这些问题代表了我们对中枢神经系统如何学习、计划和执行复杂运动行为的理解的主要差距。了解感官模式如何无缝集成，以实现手-物交互的高级内部表征，将启发设计更灵巧的具有感官反馈的机器人操纵器，改进神经假肢，并帮助开发先进的生物工程研究工具来量化生物控制机制。这项合作研究的总体目标是阐明负责建立手-物体相互作用的高级表示的机制，考虑到末端执行器的位置和力。本研究的目的是：1)量化手-物交互过程中感觉运动整合权重的机制；2)确定已习得的手-物交互在新环境中的泛化原则。研究人员将测试三个假设：1)根据其在给定任务时期内的作用，不同感觉模式的权重是时间依赖的；2)末端执行器力和位置之间的共变是手-物体相互作用的一般特征，与使用的执行器（指尖、整只手或两只手）无关；3)学习到的手-物交互的泛化对学习到的参照系很敏感。

How people use their hands to interact with objects is one of the most complex and least understood sensorimotor skills. For example, when people pick up the same object multiple times they use different fingertip forces to compensate for differences in their fingertip positions. This compensation is important because it allows people to manipulate an object skillfully without having always to grasp it at the exact same points. Several important questions remain: What is the relative contribution of individual sensory modalities, such as touch and vision, in enabling the compensatory modulation of fingertip force and position? Are fingertip forces and positions represented separately by the central nervous system? What are the mechanisms underlying their generalization to different limbs or tasks? These questions represent a major gap in our understanding of how the central nervous system learns, plans, and executes complex motor behaviors. An understanding of how sensory modalities are seamlessly integrated to enable the development and implementation of high-level internal representations of hand-object interactions should inspire the design of more dexterous robotic manipulators endowed with sensory feedback, improve neuroprosthetics, and aid development of advanced bioengineering research tools to quantify biological control mechanisms.The overall goal of this collaborative research is to elucidate the mechanisms responsible for building high-level representations of hand-object interactions accounting for end-effector position and force. The aims are 1) to quantify the mechanisms underlying the weighting of sensorimotor integration during hand-object interactions and 2) to determine the principles underlying generalization of a learned hand-object interaction to a new context. The investigators will test three hypotheses: 1) the weighting of different sensory modalities is time dependent according to its role within a given task epoch; 2) co-variation between end-effector force and position is a general feature of hand-object interactions, independent of the effectors used (fingertip, whole hand, or two-hands); and 3) generalization of learned hand-object interactions is sensitive to the frame of reference in which they were learned.