Targeting and Stimulating Cortical Area 3a to Restore Proprioception

项目概要/摘要： 本研究的更大目标是获得基础知识，并证明 使用皮层内微刺激（ICMS）恢复手臂肌肉力量的感知 区域3A。恢复这种特殊的感觉知觉对瘫痪的人来说尤其重要 使用脑控制的功能性电刺激（FES）的外周神经， 脊髓损伤后通过思考恢复手臂运动。拮抗剂的适当平衡 在这个人群中，肌肉力量对于维持肢体稳定性和减少肌肉力量至关重要。 疲劳和电池耗尽。在目标1中，我们将使用灵长类动物成像和手术计划软件 为了将定制的慢性微丝电极阵列植入到中央手肘区域深处， 两个恒河猴（共四个半球）的沟，以瞄准难以到达的 躯体感觉区3a。区域3a接收来自高尔基腱的一系列本体感受信号 器官（传达肌肉力量）和肌梭纤维（传达肌肉长度和变化， 长度），并应提供与优化FES最直接相关的肌肉特异性感知 手臂运动恢复。然而，大多数关于3a本体感受编码的知识 是从急性记录中收集的。在本研究中，我们将使用慢性微电极 记录和一系列主动和被动的感觉运动任务， 表征3a编码。然后，这些数据将用于量化相对函数， 这些不同感觉编码特征在空间尺度上的空间分布 与通过ICMS恢复这些感觉有关。在第二个目标中，我们将使用一种新的力量 跟踪游戏，以测试动物感知力主导电极位置的ICMS的能力 肌肉力量的增加。这个游戏的目的是防止动物只是学习 为了奖励而对某种不自然的“感觉”做出反应，并将验证受试者是否 实际上是在运动规划中利用力觉。最后，我们将进行这些测试 使用一系列刺激参数来量化力感知的大小， 刺激参数的函数。

Project Summary/Abstract: The larger goal of this study is to gain foundational knowledge and demonstrate the feasibility of restoring percepts of arm muscle force using intracortical microstimulation (ICMS) in cortical area 3a. Restoring this specific sensory percept is particularly important to paralyzed individuals that use brain-controlled functional electrical stimulation (FES) of their peripheral nerves to restore arm movements by thought after spinal cord injury. Appropriate balancing of antagonist muscle forces in this population is critical for maintaining limb stability and minimizing muscle fatigue and battery drain. In Aim 1, we will use primate imaging and surgical planning software to implant custom chronic microwire electrode arrays deep into the elbow region of the central sulcus of two Rhesus macaques (four hemispheres total) to target the difficult-to-reach somatosensory area 3a. Area 3a receives a range of proprioceptive signals from Golgi tendon organs (conveys muscle force) and muscle spindle fibers (conveys muscle length and change in length) and should provide muscle-specific percepts most directly relevant to optimizing FES arm movement restoration. However, most of what is known about 3a proprioceptive encoding has been collected from acute recordings. In this study, we will use chronic microelectrode recordings and a range of active and passive sensorimotor tasks across days to more fully characterize 3a encoding. These data will then be used to quantify the relative function and spatial distribution of these different sensory encoding characteristics on the spatial scale relevant to restoring these sensations via ICMS. In the second aim, we will use a novel force tracking game to test the animals' ability to perceive ICMS of force-dominant electrode locations as an increase in muscle force. This game is designed to prevent the animals from just learning to respond to some unnatural `sensation' for a reward and will verify that the subjects are actually utilizing the force percepts in their motor planning. Finally, we will conduct these tests using a range of stimulus parameters to quantify the magnitude of the force percepts as a function of stimulation parameters.