Neural Mechanisms of Cutaneous Spatial Integration

该项目分析了顶叶体感神经元在熟练表演过程中的作用 手动任务。它旨在了解手如何通过感官获取有关物体的信息。 触觉和本体感觉，并利用它来掌握和操纵它们。我们使用一个扩展任务，其中 手抓住和操纵物体，作为一个模型系统，以检查如何感官线索和以前的 经验用于计划和实施熟练的手部行为。我们假设在主动触摸过程中， 感觉流入的内部表征是通过运动系统的必然放电来实现的 这样受试者就能预测预期行为的感官后果。中央和 外围信号允许后顶叶皮层（PPC）的神经元比较预测和现实。的 感官反应是在任务目标的背景下感知的。多个电极记录尖峰序列， S-I和PPC中的局部场电位以及手部运动学的测量，评估时间关系 在代表手指的神经群之间。我们建议PPC中的预期接触前活动 反映了有效抓取物体并确保其可操作所需的任务规划。接触后 S-I的活动证实或反驳了受试者对触觉特征的期望，并提供了所需的反馈， 错误修正目的1分析了自上而下的认知控制的感觉反馈的变化信息 由cue提供。我们研究如何在PPC中表示对象的形状和位置时，它是 用不同的指示和期望来把握。目的2研究双侧手的神经控制 通过比较由左手和右手执行的时间上解耦的抓握动作， 类似的运动，需要协调和协同行动的手。同时使用双边 记录从左，右半球，我们检查是否这样的行为涉及神经元在每个 大脑半球专门用于双手动作，或者通过两个半球的同步激活来实现 半球目的3探索当线索模糊时，PPC在决策中的作用。我们评估 利手偏好、奖励概率和短期记忆在选择使用的手中的作用， 在每次审判中抓住的对象。这项研究提供了基本的见解的动态组织皮层 电路，预测在正常手部使用中的作用，以及体感信息之间的整合 手指精细运动控制所需的大脑半球。对这些皮层过程的理解可能 对神经系统疾病如中风或周围神经的康复具有临床重要性 损伤从这项研究中得出的感觉运动整合原则可能有助于更好地发展 感觉假体或基于手功能的生物模型的机器人操纵器。

This project analyzes the role of somatosensory neurons in the parietal lobe during performance of skilled manual tasks. It aims to understand how the hand acquires information about objects through the senses of touch and proprioception, and uses it to grasp and manipulate them. We use a prehension task, in which the hand grasps and manipulates objects, as a model system to examine how sensory cues and previous experience are used to plan and implement skilled hand behaviors. We hypothesize that during active touch, internal representations of the sensory inflow are implemented by corollary discharge from the motor system so that the subject can predict the sensory consequences of intended actions. Convergence of central and peripheral signals allows neurons in posterior parietal cortex (PPC) to compare predictions and reality. The sensory responses are perceived in the context of task goals. Multiple electrode recordings of spike trains and local field potentials in S-I and PPC, and measurements of hand kinematics, assess temporal relations between neural populations representing the fingers. We propose that anticipatory precontact activity in PPC reflects task planning needed to grasp objects efficiently and to secure them for manipulation. Post-contact activity in S-I confirms or rebuts the subject¿s expectation of haptic features, and provides feedback needed for error correction. Aim 1 analyzes top-down cognitive control of sensory feedback by varying information provided by the cue. We examine how the shape and location of an object are represented in PPC when it is grasped with different instructions and expectations. Aim 2 examines the neural control of bilateral hand movements by comparing temporally uncoupled grasping actions performed by the left and right hands, with similar movements that require coordinated, and synergistic actions of the hands. Using simultaneous bilateral recordings from left and right hemispheres, we examine whether such behaviors involve neurons in each hemisphere specialized for bimanual actions, or are implemented by synchronous activation of the two hemispheres. Aim 3 explores the role of PPC in decision making when cues are ambiguous. We assess the role of handedness preferences, reward probability and short-term memory in choice of the hand used and object grasped in each trial. This research provides basic insights into the dynamic organization of cortical circuits, the role of prediction in normal hand use, and integration of somatosensory information between hemispheres needed for fine motor control of the fingers. An understanding of these cortical processes may have clinical importance for rehabilitation following neurological disorders such as stroke or peripheral nerve injury. Principles of sensorimotor integration derived from this research may prove useful for developing better sensory prostheses or robotic manipulators based on biological models of hand function.