Encoding of Reach-to-Grasp in the Primary Motor Cortex

初级运动皮层中伸手抓握的编码

基本信息

批准号：
7082190
负责人：
TIMOTHY J EBNER
金额：
$ 27.43万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-01-01 至 2008-06-30
项目状态：
已结题

项目摘要

The global problem addressed by this proposal is how does the central nervous system (CNS) control a structure as complex as the primate hand? To begin to address this question, four Specific Aims are proposed that address three outstanding issues in the neural control of reach-to-grasp. The studies will use chronic single unit recordings in the primary motor cortex (M1) of monkeys trained to perform various reach-to-grasp movements. Extensive monitoring of arm and hand kinematics, grasp forces and the activity of arm and extrinsic/intrinsic muscles of the hand will be done. Statistical and analytical tools including regression analyses and data reduction techniques will be used to extract the neural representation of hand shape/object shape, kinematics, grasp forces and EMG activity. First, findings from psychophysical, lesion, and electrophysiological studies suggest that the CNS, at least in part, reduces the number of degrees of freedom by controlling the hand as a unit. Specific Aims 1 and 2 will address the hypothesis that neurons in the hand area of M1 encode and control hand shape/object properties, reflecting this global control of the hand. Second, early investigations into hand movements categorized prehension into two broad classes, power and precision grip and more elaborate classification systems followed. A prediction of these categorical schemes is that the CNS explicitly controls grasp type. More recent psychophysical studies, however, suggest that a strict division of hand posture into power and precision grasps does not occur. Specific Aim 3 will test the alternative hypothesis that power and precision are part of a continuum of hand postures in which hand shape is primarily controlled. A third major contemporary hypothesis is that reach and grasp are controlled by two independent but coupled channels: a "transport" channel that extracts information about the spatial location of objects to guide the reach and a "manipulation" channel that extracts information about the intrinsic properties of the object such as size and shape to guide hand shape. Although psychophysical results suggest that the two components are coupled, there is virtually no single unit data addressing this question. In Specific Aim 4 the hypothesis is tested that the reach and grasp components are coupled at the neuronal level in M1. In general understanding how the CNS controls prehension is a critical step in understanding human movements. In the future understanding the signals controlling grasp could prove useful for controlling prosthetic devices in patients with brain injury.

该提案解决的全球性问题是中枢神经系统（CNS）如何控制像灵长类动物的手这样复杂的结构？为了开始解决这个问题，提出了四个具体目标，解决了抓取的神经控制中的三个突出问题。这些研究将使用经过训练执行各种伸手抓握动作的猴子初级运动皮层（M1）的慢性单单位记录。将广泛监测手臂和手的运动学、抓握力以及手臂和手的外在/内在肌肉的活动。包括回归分析和数据缩减技术在内的统计和分析工具将用于提取手形/物体形状、运动学、抓握力和肌电图活动的神经表征。首先，心理物理学、损伤和电生理学研究的结果表明，中枢神经系统（至少部分）通过将手作为一个整体进行控制而减少了自由度。具体目标 1 和 2 将解决这样的假设：M1 手部区域的神经元编码和控制手部形状/物体属性，反映手部的这种全局控制。其次，对手部动作的早期研究将抓握分为两大类：强力抓握和精确抓握，以及随后更复杂的分类系统。这些分类方案的预测是中枢神经系统明确控制抓取类型。然而，最近的心理物理学研究表明，并没有将手部姿势严格划分为力量和精确握持。具体目标 3 将检验另一种假设，即力量和精度是手部姿势连续体的一部分，其中手部形状主要受到控制。第三个主要的当代假设是，触及和抓取是由两个独立但耦合的通道控制的：一个“传输”通道，用于提取有关物体空间位置的信息以指导触及；一个“操纵”通道，用于提取有关内在属性的信息物体的大小和形状等来指导手的形状。尽管心理物理学结果表明这两个组成部分是耦合的，但实际上没有单个单元数据可以解决这个问题。在特定目标 4 中，测试了假设，即触及和抓握组件在 M1 的神经元水平上耦合。一般来说，了解中枢神经系统如何控制抓握是理解人类运动的关键一步。将来，了解控制抓握的信号可能有助于控制脑损伤患者的假肢装置。