Motor Cortical Function During Motor Learning with a Brain-Machine Interface

 描述(申请人提供)：脑机接口(BMI)承诺恢复瘫痪个人的自愿运动，通过使用他们自己的神经活动来控制计算机光标、机械臂，甚至他们自己的肢体的运动。一类“仿生的”BMI研究渴望让患者通过想象自然的肢体运动来控制BMI。然而，当实验猴子从正常运动过渡到控制BMI时，控制神经元以一种表明运动学习的方式改变了它们的放电模式。随着猴子表现达到顶峰，这些变化会在几个阶段发生，这表明尽管如此，仍有必要学习神经活动和所需动作之间的新映射。我建议的目标是通过更好地了解在正常运动任务和BMI范例中，皮质神经元的活动在运动学习过程中如何以及为什么变化，从而改善BMI控制。我将研究两个功能不同的运动皮质区域，初级运动皮质(M1)和背侧运动前皮质(PMD)是如何协同工作来协调运动的。更好地了解这些区域在正常运动中的作用将使我们能够设计更多的仿生BMI。由于适应BMI使用和传统运动学习有明显的相似之处，我建议首先研究在两个常见的运动学习任务中，运动皮质神经元的运动相关活动是如何变化的。已知M1和PMD在伸展中具有不同的作用，M1的活动与肢体动力学和肌肉激活密切相关，PMD编码运动目标和规划。这些区域神经元的不同功能行为表明，它们在控制体重指数方面的效用可能不同。我首先提议研究M1和PMD如何在猴子在两种扰动下进行伸展运动时改变它们的排泄量：速度相关的力场(“旋度场”)和静态视觉运动旋转。我将使用神经空间调谐分析方法，以及通过推断神经元之间功能连接的变化，来研究这两个神经群体如何改变以调节适应。在第二个目标中，我将扩展我的实验，包括一项BMI任务，以更好地了解在使用BMI期间观察到的皮质变化。猴子将使用M1或PMD神经元在多个会话中控制光标。随着猴子的适应，我将描述BMI技能获得背后的空间调整或功能连接方面的变化。此外，我还将测试M1控件和PMD控件之间的差异(如果有)。这两个目标的结果将有助于理解运动学习的神经基础，M1和PMD如何协同工作来协调运动，以及M1和PMD如何被用来创造更具仿生性的BMI。

 DESCRIPTION (provided by applicant): Brain-machine interfaces (BMIs) promise to restore voluntary movement to paralyzed individuals by using their own neural activity to control movement of computer cursors, robotic arms, or even their own limbs. A class of "biomimetic" BMI research aspires to allow patients to control the BMI by imagining natural limb movements. However, as experimental monkeys transition from normal movements to controlling a BMI, the control neurons alter their discharge patterns in a manner indicative of motor learning. These changes, which occur over several sessions as the monkeys achieve peak performance, suggest there is nonetheless, a need to learn a new mapping between neural activity and the desired movements. The goal of my proposal is to improve BMI control through a better understanding of how and why the activity of cortical neurons changes during motor learning during both normal motor tasks and a BMI paradigm. I will investigate how two functionally distinct motor cortical areas, primary motor cortex (M1) and dorsal premotor cortex (PMd), work together to coordinate movements. A better understanding of the role of these areas in normal movements will allow us to design more biomimetic BMIs. Due to the apparent similarity between adapting to BMI use and traditional motor learning, I propose first to study how movement-related activity of motor cortical neurons changes during two common motor learning tasks. M1 and PMd are known to have different roles in reaching, with M1 activity that is closely related to limb dynamics and muscle activation and PMd encoding movement goals and planning. The different functional behavior of neurons in these areas suggests that they may differ in their utility for BMI control. I first propose to study how M1 and PMd alter their dischage as monkeys make reaching movements in the presence of two perturbations: a velocity-dependent force field ("curl field") and a static visuomotor rotation. I will study how the two neural populations change to mediate adaptation using neural spatial tuning analysis methods as well as by inferring changes in functional connectivity between neurons. In the second aim, I will extend my experiments to include a BMI task to better understand the cortical changes observed during BMI use. Monkeys will use either M1 or PMd neurons to control a cursor over multiple sessions. As the monkeys adapt, I will characterize the changes in spatial tuning or functional connectivity underlying BMI skill acquisition. Additionally, I will test for what differences, if any, exist between M1 control and PMd control. The results of these two aims will help to understand the neural basis of motor learning, how M1 and PMd work together to coordinate movements, and how M1 and PMd might be used to create a more biomimetic BMI.