Coding of action by motor & premotor cortical ensembles

这个项目的目标是了解单个神经元以及相互作用的神经元集合是如何 多个运动皮质区域在伸手抓握行为中协调近端和远端组件。虽然 心理物理学研究已经确定，抓握运动涉及手部运输的协调。 而抓握预成型，对皮层参与协调伸展和抓握知之甚少。 大多数电生理记录都集中在描述大脑皮质单个神经元的放电。 分别与伸手或抓握动作有关。我们将确定：1)单个神经元如何 背侧前运动(PMD)、腹侧前运动(PMV；F5)和初级运动(MI)皮质区编码两个REACH 并通过显式刻画触达-抓取协调的编码来抓取成分；2)是否 在这三个皮质区域内，REACH和GRAPH神经元有一个地形图组织； 在同时记录的神经元之间是否存在结构化的时空模式的峰电位 调解触手可及的协调。为了实现这一点，高密度电极阵列将 在MI、PMV和PMD中长期植入，从中将产生100个单位和局部场势 当猴子伸手抓住不同大小、形状和方向的物体时，同时记录下来 在不同的三维位置。一种使用六台红外摄像机的数字光学跟踪系统 将监控手臂和手在伸手抓握行为中的运动学。一组统计和 数学方法将被用来开发REACH-to-GRAPH的编码模型，该模型捕捉到如何单一 神经元放电和神经元丛活动参与手部运输和握力的协调 光圈运动学。解码模型也将被用来比较MI内的合奏活动有多好， PMV和PMD可以重建伸展和抓取运动学。更复杂的伸手抓握动作 涉及避障和抓取移动物体将被用来测试这些编码和 解码模型概括为改变的协调模式。 项目叙事 协调的到达和抓住是人类行为的一个普遍特征，可以追溯到它的进化根源 在树栖环境中觅食的灵长类动物，并允许发展更复杂的 行动包括使用工具，并最终通过直接接触获得知识。拟议中的项目 将加强我们对大脑皮层对这些协调行为的贡献的理解，这可能导致 对因中风或损伤而导致皮质损伤的运动障碍患者进行更有效的康复治疗。 这项工作对神经运动假体的开发也有直接的意义，通过这种假体，脊椎 脊髓损伤或肌萎缩侧索硬化症患者可能能够控制抓握以及人工运输组件 通过激活运动皮质神经元的集合来激活设备。

The goal of this project is to understand how single neurons as well as ensembles of interacting neurons in multiple motor cortical areas coordinate proximal and distal components in reach-to-grasp behavior. Although psychophysical research has determined that prehensile movements involve the coordination of hand transport and grasp preshaping, very little is known about the cortical involvement in coordinating reach and grasp. Most electrophysiological recordings have focused on characterizing the firing of single cortical neurons in relation to either reaching or grasping movements separately. We will determine: 1) how single neurons within dorsal premotor (PMd), ventral premotor (PMv; F5), and primary motor (MI) cortical areas encode both reach and grasp components by explicitly characterizing the encoding of reach-to-grasp coordination; 2) whether there is a topographic organization of reach and grasp neurons within these three cortical areas; and 3) whether there are structured spatiotemporal patterns of spiking among simultaneously recorded neurons that mediate the coordination of reach-to-grasp. To accomplish this, high-density electrode arrays will be chronically implanted in MI, PMv, and PMd from which 100s of single units and local field potentials will be simultaneously recorded while monkeys reach for and grasp objects of different sizes, shapes, and orientations in different three-dimensional locations. A digital optical tracking system using a set of six infrared cameras will monitor the kinematics of the arm and hand during reach-to-grasp behavior. A set of statistical and mathematical methods will be employed to develop encoding models of reach-to-grasp that capture how single neuron spiking and neuronal ensemble activity participate in the coordination of hand transport and grip aperture kinematics. Decoding models will also be used to compare how well ensemble activity within MI, PMv, and PMd can reconstruct the reach and grasp kinematics. More complex reach-to-grasp movements involving obstacle avoidance and grasp of moving objects will be used to test whether these encoding and decoding models generalize to altered coordination patterns. Project Narrative Coordinated reaching and grasping is a ubiquitous feature of human behavior that traces its evolutionary roots to primate foraging for food in arboreal environments and has allowed for the development of more complex actions including tool use and, ultimately, knowledge acquisition through direct contact. The proposed project will enhance our understanding of the cortical contribution to these coordinated behaviors which may lead to more effective rehabilitative treatments for motor disabled patients with cortical damage due to stroke or injury. This work also has direct relevance towards the development of a neuro-motor prosthesis by which spinal cord-damaged or ALS patients may be able to control grasp as well as transport components of artificial devices by activating ensembles of motor cortical neurons.