Neural Mechanisms of Cutaneous Spatial Integration

描述（由申请人提供）：本项目分析在执行熟练的手工任务时顶叶体感神经元的作用。我们使用一个抓握任务，其中手抓住和操纵物体，作为一个模型系统来研究如何使用感官线索和先前的经验来计划和实施熟练的手部运动。它旨在理解关于物体的信息是如何被手通过触觉、本体感觉和视觉获得的。我们认为感觉反应是在任务目标的背景下被感知的。假设后顶叶皮层（PPC）的神经活动反映了有效抓取物体和确保操作所需的任务计划。初级体感皮层（S-I）的神经反应证实或反驳受试者对物体特征的期望，并提供纠正错误所需的反馈。我们将使用多个电极阵列和手部运动的数字视频测量来记录任务执行过程中PPC和S-I神经群的尖峰序列和局部场电位。目的1分析由行为线索提供的感觉信息在调节抓取神经反应中的作用。我们研究了一个对象的形状和位置是如何在PPC中表示的，当它被不同的指令和期望所掌握。这些研究验证了这样的假设，即物体特征的行为相关性改变了在任务规划过程中形成的运动程序，以及在任务执行过程中从手反馈到皮层的体感信息。目的2研究了当双手同时进行相同动作时，双侧手运动的神经控制。我们将通过比较由左手和右手分别执行的暂时不耦合的抓取动作，与需要两只手协调和协同动作的类似双手运动，量化每个半球中对两只手执行的类似动作做出相同反应或专门用于双手动作的双侧神经元的流行程度。我们还研究了双手行为是否通过左右顶叶皮层的同步记录来实现两个半球的同步双侧激活。目的3探讨了当线索不明确时，PPC在决策中的作用。在每个实验中，我们评估了惯用手偏好、奖励概率和短期记忆在选择使用的手和掌握的物体中的作用。这项研究为大脑皮层回路的动态组织、预测在正常手部使用中的作用以及控制手部精细运动所需的大脑半球间体感信息的整合提供了基本的见解。了解这些皮层过程对中风或周围神经损伤等神经系统疾病的康复具有重要的临床意义。从这项研究中得出的感觉运动整合原理可能有助于开发基于手功能生物学模型的更好的感觉假肢或机器人操纵器。该项目分析了大脑皮层顶叶神经元在执行熟练手工任务时的作用。它旨在了解手是如何通过触觉和本体感觉获得物体的信息，并在熟练地抓住和操纵物体时被大脑使用。了解这些脑机制对于中风或周围神经损伤等神经系统疾病后的手部功能康复，以及基于手部功能的生物学模型开发更好的感觉假体或机器人操纵器具有临床意义。

DESCRIPTION (provided by applicant): This project analyzes the role of somatosensory neurons in the parietal lobe during performance of skilled manual tasks. 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 movements. It aims to understand how information about objects is acquired by the hand through the senses of touch, proprioception, and vision. We propose that sensory responses are perceived in the context of task goals. Neural activity in the posterior parietal cortex (PPC) is hypothesized to reflect task planning needed to grasp objects efficiently and to secure them for manipulation. Neural responses in the primary somatosensory (S-I) cortex confirms or rebuts the subject's expectation of object features, and provides feedback needed for error correction. We will record spike trains and local field potentials of neural populations in PPC and S-I during performance of the task using multiple electrode arrays and digital video measurements of hand kinematics. Aim 1 analyzes the role of sensory information provided by the behavioral cue in modulating neural responses to prehension. We examine how the shape and location of an object are represented in PPC when it is grasped with different instructions and expectations. The studies test hypotheses that the behavioral relevance of object features modifies the motor program developed during task planning, and somatosensory information fed back to the cortex from the hand during task performance. Aim 2 addresses the neural control of bilateral hand movements when both hands perform the same movements together. We will quantify the prevalence of bilateral neurons in each hemisphere that respond equivalently to similar actions performed by each hand, or are specialized for bimanual actions, by comparing temporally uncoupled grasping movements performed separately by the left and right hands, with similar bimanual movements that require coordinated and synergistic actions of the two hands. We also examine whether bimanual behaviors are implemented by synchronous bilateral activation of the two hemispheres using simultaneous recordings from the left and right parietal cortex. 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 hand. 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. This project analyzes the role of neurons in the parietal lobe of the cerebral cortex during performance of skilled manual tasks. It aims to understand how information about objects is acquired by the hand through the senses of touch and proprioception, and is used by the brain when objects are grasped and manipulated skillfully. An understanding of these brain mechanisms may have clinical importance for rehabilitation of hand function following neurological disorders such as stroke or peripheral nerve injury, and for development of better sensory prostheses or robotic manipulators based on biological models of hand function.