Coding of action by motor & premotor cortical ensembles

电机动作编码

• 批准号: 6895493
• 负责人: Nicholas G Hatsopoulos
• 金额: $ 27.38万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6895493
• 关键词: Macaca mulatta; arm; behavior test; behavioral /social science research tag; biomechanics; electrodes; electrophysiology; mathematics; motor cortex; motor neurons; neuromuscular system; neurons; psychomotor function

DESCRIPTION (provided by applicant): The objective of this project is to understand what and how movement features are encoded in ensembles of interacting motor cortical neurons. Although previous electrophysiological research has focused on encoding in single motor cortical neurons, very little work has examined whether spatial-temporal patterns of activity emerging from ensembles of interacting neurons encode features of movement planning and execution. To test this hypothesis, high-density electrode arrays will be chronically implanted in primary motor cortex (MI) and dorsal premotor cortex (PMd) from which 100s of single units will be simultaneously recorded while monkeys perform complex visuo-motor tasks with the arm. A continuous random-tracking task and a step random-tracking task are ideally suited to investigate neural encoding because they uncouple the statistical dependencies among many of the relevant motor variables, more thoroughly sample the movement space, and reduce non-stationarities. Forward and reverse correlation, information-theoretic, and decoding methods will be used to analyze the encoding problem as well the information mapping between the two cortical areas. Two specific aims are proposed in this project. First, kinematic and kinetic tuning properties of motor cortical ensembles will be investigated and compared to single neuron tuning functions under different behavioral contexts. The stability of these tuning functions will be examined by applying different external loads to the arm, varying the behavioral mode (freely moving vs. isometric), or changing the posture of the forearm. Second, it will determined whether spatio-temporal patterns within motor cortical ensembles can be elicited by altering the temporal dynamics and predictability of the movement. This work is significant because it will elucidate how groups of interacting cortical neurons control and coordinate complex movements and will provide an important step in understanding how neuronal ensembles in other cortical areas represent other high-level functioning. In addition, this work has direct relevance towards the development of a neuro-motor prosthesis by which paralyzed patients may be able to control external devices by activating their cortex.

描述(由申请人提供)：本项目的目标是了解在相互作用的运动皮质神经元集合中，运动特征是什么以及如何编码的。虽然以前的电生理学研究主要集中在单个运动神经元的编码上，但很少有工作研究从相互作用的神经元集合中产生的活动的时空模式是否编码了运动计划和执行的特征。为了验证这一假设，高密度电极阵列将被长期植入初级运动皮质(MI)和背侧运动前皮质(PMD)，在猴子用手臂执行复杂的视觉运动任务时，将从这些区域同时记录100个单一单位。连续随机跟踪任务和阶跃随机跟踪任务非常适合于研究神经编码，因为它们分离了许多相关运动变量之间的统计依赖关系，更彻底地对运动空间进行采样，并减少了非平稳性。我们将使用正向和反向相关、信息论和解码方法来分析编码问题以及两个大脑皮层区域之间的信息映射。本项目提出了两个具体目标。首先，将研究运动皮质集合的运动学和运动学调谐特性，并将其与不同行为背景下的单个神经元调谐函数进行比较。这些调谐功能的稳定性将通过对手臂施加不同的外部负载、改变行为模式(自由运动与等长运动)或改变前臂的姿势来检查。其次，它将确定是否可以通过改变运动的时间动力学和可预测性来引发运动皮质集合中的时空模式。这项工作意义重大，因为它将阐明相互作用的皮质神经元组如何控制和协调复杂的运动，并将为理解其他皮质区域的神经元集合如何代表其他高级功能提供重要的一步。此外，这项工作与神经运动假体的开发有直接关系，通过这种假体，瘫痪患者可能能够通过激活他们的皮质来控制外部设备。