Visuomotor Prosthetic for Paralysis

拟议研究的目标是获得视觉运动转换的科学知识。 四肢瘫痪患者的后顶叶皮质和初级运动皮质 努力推进神经假体的发展。我们已经在进行的临床试验中证明了 在过去的6年里，PPC可以控制神经假体来辅助四肢瘫痪患者。其他团体 专注于M1，同样也找到了神经假体的控制力。在我们对PPC的研究中，我们有 研究发现，除了移动机械臂或控制计算机光标的轨迹信号外，还有 过多的视觉运动信号，代表身体大部分的预期运动，运动 目标、认知策略，甚至是记忆信号。我们的中心假设是购买力平价和M1将 以相似和不同方式对视觉运动参数进行编码，且算法可以 开发的目的是利用来自两个领域的信号来改善假体 射程和性能。将在M1和PPC中进行植入，从而能够同时在 相同的主题，引发了对从不同实验室收集的不同数据进行比较的担忧 有不同植入物和不同任务的人。 这一中心假设将在两个广泛的目标中得到检验，我们有大量的初步数据。 目标1将考察这两个区域对身体的控制。据推测，M1将 对侧肢体表现出很强的特异性(植入的是手部的旋钮) 而PPC将编码身体大部分以及对侧和同侧的运动，通过 利用其参数的部分混合编码(次级目标1a)。而M1被假设为编码 空间变量仅在尝试或想象的动作期间，假设PPC也 在任务适当的参照系中编码认知空间变量(次级目标1b)。在子目标1c中，我们 将研究多个身体部位是如何在运动表示中组合的，假设 M1和PPC将使用一套不同的机制，包括线性求和、非线性求和、 组合和运动抑制以不同的方式表现为脑区和 特定的动作集。 目标2将研究这两个领域中编码的时间方面。在子目标2a中，我们将测试 假设持续运动期间的神经动力学在很大程度上不会改变 两个地区都有。在子目标2b中，我们假设在顺序运动期间，M1只编码 正在进行的运动，而PPC编码当前和随后的运动。最后，在子目标中 2C我们将研究移动速度的编码，假设有独立的 M1和PPC中用于移动方向和速度的子空间。

The objective of the proposed research is to obtain scientific knowledge of visuomotor transformations in posterior parietal cortex (PPC) and primary motor cortex (M1) from tetraplegic subjects in a clinical trial to advance the development of neural prosthetics. We have shown in clinical trials conducted over the past 6 years that PPC can control neural prosthetics for assisting tetraplegic subjects. Other groups have concentrated on M1 and likewise find control for neural prosthetics. In our studies of PPC we have found that besides trajectory signals to move robotic limbs or control computer cursors, there are a plethora of visuomotor signals that represent intended movements of most of the body, movement goals, cognitive strategies, and even memory signals. Our central hypothesis is that PPC and M1 will encode visuomotor parameters in both similar and different ways, and that algorithms can be developed to leverage those signals from the two areas that are complimentary to improve prosthetic range and performance. Implants will be made in both M1 and PPC, enabling simultaneous recording in the same subjects, elevating concerns of comparing data from different labs collected in different individuals with different implants and different tasks. This central hypothesis will be tested in two broad aims, for which we have substantial preliminary data. Aim 1 will examine the control of the body by the two areas. It is hypothesized that M1 will demonstrate strong specificity for the contralateral limb (implants will be made in the hand knob) whereas PPC will code movements for most of the body and on both contra and ipsilateral sides by leveraging its partially mixed encoding of parameters (subaim 1a). Whereas M1 is hypothesized to code spatial variables exclusively during attempted or imagined actions, it is hypothesized that PPC also encodes cognitive spatial variables in task appropriate reference frames (subaim 1b). In subaim 1c we will examine how multiple body parts are combined in movement representations, hypothesizing that M1 and PPC will employ a diverse set of mechanisms including linear summation, non-linear combinations, and movement suppression expressed in different ways as a function of brain area and the specific movement set. Aim 2 will examine the temporal aspects of encoding in the two areas. In subaim 2a we will test the hypothesis that the neural dynamics during sustained periods of movement are largely unchanging in both areas. In subaim 2b we hypothesize that, during sequential movements, M1 codes only the ongoing movement whereas PPC codes both the current and subsequent movements. Finally, in subaim 2c we will examine the coding of movement speed, with the hypothesis that there are separate subspaces in both M1 and PPC for direction and speed of movement.