Sensory motor transformations in human cortex

翻译后摘要：本申请的长期目标是了解皮层处理的感觉， 人类大脑皮层的运动转换。大量的计算必须 以实现传感器引导的电机控制。在这些计算中，视觉 行动目标的信息必须从视网膜的坐标转换到视网膜的坐标。 用于移动的效应器的坐标，例如用于在视觉下到达的肢体坐标 指导和世界坐标在环境中的相互作用。一旦物体被抓住， 需要来自手的体感信号来灵巧地操纵所抓物体。内部 感觉运动通路内的模型对于估计身体的当前状态和运动状态是必不可少的。 外部环境，解释感官反馈的滞后，并校准身体以适应 环境 我们将利用能够在临床上记录单个神经元群体的难得机会， 这项研究旨在为因脊髓损伤而瘫痪的四肢瘫痪患者开发神经修复术。 微电极阵列的皮层植入物将在感觉运动的三个关键位置内进行 系统：初级运动皮层、初级躯体感觉皮层和后顶叶皮层。这些 微电极阵列能够进行记录和皮质内微刺激。 我们将检验躯体感觉和运动皮层代表想象中的手的范围的假设 协调，但后顶叶皮层是任务依赖性的，其群体神经活动可以灵活地 改变坐标框架以实现身体（手臂和眼睛）内的空间关系的编码， 在身体和世界之间（武装和达到目标;相对于自我的物体），以及在世界之内（相对 对象在世界中的位置）。皮层内刺激诱发的知觉 微刺激和想象的感觉将被用来理解皮肤和 在初级躯体感觉皮层和后顶叶皮层内的本体感受信息。的 要测试的假设是，想象的感觉和电诱发的感觉是高度 不仅在初级躯体感觉皮层，而且在后顶叶皮层。最后我们 假设后顶叶皮层包含人类内部的状态估计模型， 显示出自然行为和大脑控制行为的可塑性，并将这种学习转移到运动皮层。 这些研究不仅将大大推进我们对人类感觉运动皮层回路的理解， 也将为未来神经修复体的设计提供基础知识。

Abstract: The long-term objective of this application is to understand cortical processing of sensory to motor transformations within the human cerebral cortex. A vast number of computations must be performed to achieve sensory-guided motor control. Standing out among these computations, visual information of the goals of action must be transformed from the coordinates of the retina to the coordinates of effectors used for movement, for instance limb coordinates for reaching under visual guidance and to world coordinates for interactions in the environment. Once an object is grasped, somatosensory signals from the hand are required for dexterous manipulation of grasped objects. Internal models within the sensory motor pathway are essential for estimating the current state of the body and the external environment, accounting for lags in sensory feedback, and calibrating the body to the environment. We will use the rare opportunity of being able to record from populations of single neurons in a clinical study designed to develop neural prosthetics for tetraplegic participants paralyzed by spinal cord injuries. Cortical implants of microelectrode arrays will be made within three key locations in the sensorimotor system: primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. These microelectrode arrays enable both recording and intracortical microstimulation. We will test the hypothesis that somatosensory and motor cortex represent imagined reaches in hand coordinates, but posterior parietal cortex is task dependent, and its population neural activity can flexibly change coordinate frames to enable encoding of the spatial relations within the body (arm and eyes), between the body and world (arm and reach targets; objects relative to self), and within the world (relative position of objects in the world) as required by task demands. Percepts evoked by intracortical microstimulation and imagined sensations will be used to understand the representation of cutaneous and proprioceptive information within primary somatosensory cortex and posterior parietal cortex. The hypothesis to be tested is that imagined sensation and electrically evoked sensations are highly overlapping—not just in primary somatosensory cortex but also in posterior parietal cortex. Lastly, we hypothesize that the posterior parietal cortex contains in humans an internal model of state estimation that shows plasticity for both natural and brain-control behaviors and transfers this learning to motor cortex. These studies will not only greatly advance our understanding of the human sensorimotor cortical circuit, but also will provide basic knowledge for the design of future neural prosthetics.