Visuomotor adaptation in reaching

描述（由申请人提供）：从经验中学习的能力可能是高级大脑功能的最基本特征。即使是简单的行为，如目标导向的达成表现出快速和强大的适应，以应对感官反馈的变化。这些学习形式在行为层面上得到了广泛的表征，并且已经开发了各种模型来提供对这些现象的直观理解。然而，尽管取得了这些进展，但人们对潜在的神经回路如何随着学习而变化或感觉反馈如何驱动这些变化知之甚少。这个建议解决了这些问题，重点是快速学习，发生在响应转移视觉反馈的手臂（“视觉转移适应”）。已经表明，当手臂的视觉反馈从真实位置移位时，例如利用移位棱镜，在视觉定位（事物“看起来”在哪里）和本体感受定位（手臂“感觉到”在哪里）中观察到补偿性移位。这些变化使两种感觉重新对齐。为了揭示这一过程背后的生理机制，这项工作将研究视觉和本体感受如何在大脑中正常整合（“感觉整合”）以及该过程如何随着视觉转移适应（“感觉重新校准”）而变化。这将通过记录大脑皮层中几个手臂运动相关区域的神经活动来实现，因为动物在手臂的视觉反馈发生变化或未变化的情况下进行感觉引导的到达运动。同时记录大神经元群体的活动，从而可以与现有的感觉整合和重新校准的神经模型进行直接比较。目的1：探讨感觉统合的皮层机制。定量测量将作出的视觉和本体感受的神经计算的基础达到规划的贡献。具体而言，视觉反馈的相对权重是从随机交错试验中包含的各种视觉反馈变化对群体活动的影响中推断出来的。这些实验被设计为i）测试皮层区域是否对感觉输入进行加权，ii）识别哪些皮层区域随着行为改变其加权，以及iii）测试这种加权是否与统计理论的预测一致。目的二是研究感觉再校准的皮层机制。定量测量将发生在皮层的视觉和本体感受信号的变化，在延长暴露于恒定的视觉变化，驱动感觉重新校准的情况。这些实验的目的是确定i）在一个给定的皮层区域的感觉编码的变化是否可以解释为该区域的感觉输入的错位和ii）这些变化是否与统计理论的预测一致。公共卫生相关性：该项目旨在发现大脑皮层中手眼协调神经回路的新学习机制。这项工作将使我们更深入地了解我们的运动感官如何驱动我们大脑的快速变化。除了其科学影响外，这项工作还有两个潜在的医学应用：i）帮助开发用于运动控制的感觉假体装置，ii）帮助开发中风后感觉和感觉运动缺陷的新的原则性疗法。

DESCRIPTION (provided by applicant): The ability to learn from experience is perhaps the most fundamental feature of higher brain function. Even simple behaviors such as goal-directed reaching exhibit rapid and robust adaptation in response to changes in sensory feedback. These forms of learning have been extensively characterized at the behavioral level, and a variety of models have been developed to provide an intuitive understanding of these phenomena. Yet despite this progress, very little is known about how the underlying neural circuits change with learning or how sensory feedback drives these changes. This proposal addresses these questions, focusing on the rapid learning that occurs in response to shifted visual feedback of the arm ("visual-shift adaptation"). It has been shown that when visual feedback of the arm is displaced from the true position, for example with displacing prisms, compensatory shifts are observed in visual localization (where things "look" to be) and proprioceptive localization (where the arm "feels" to be). These shifts bring the two senses back into alignment. In order to uncover the physiological mechanism behind this process, this work will investigate how vision and proprioception are normally integrated in the brain ("sensory integration") and how that process changes with visual-shift adaptation ("sensory recalibration"). This will be accomplished by recording neural activity in several arm-movement related areas in cerebral cortex as animals make sensory guided reaching movements with shifted or unshifted visual feedback of the arm. The activity of large neuronal populations will be simultaneously recorded, permitting direct comparison to existing neural models of sensory integration and recalibration. Aim 1 is to study the cortical mechanism of sensory integration. Quantitative measurements will be made of the visual and proprioceptive contributions to the neural computations that underlie reach planning. Specifically, the relative weighting of visual feedback is inferred from the effect that various visual feedback shifts, included on randomly interleaved trials, have on the population activity. These experiments are designed i) to test whether cortical areas weight sensory inputs, ii) to identify which cortical areas change their weighting with behavior, and iii) to test whether this weighting is consistent with predictions from statistical theory. Aim 2 is to study the cortical mechanism of sensory recalibration. Quantitative measurements will be made of the changes that occur to visual and proprioceptive signals in cortex during extended exposure to a constant visual shift, a situation that drives sensory recalibration. These experiments are designed to determine i) whether the changes in the sensory coding in a given cortical area can be explained by the misalignment of sensory inputs to that area and ii) whether these changes are consistent with predictions from statistical theory. PUBLIC HEALTH RELEVANCE: This project is aimed at discovering new mechanisms of learning in the neural circuits for eye-hand coordination in the cerebral cortex. This work will give us a deeper understanding of how sensory of our movements drives rapid changes in our brains. In addition to its scientific impact, this work has two potential medical applications: i) to aid in the development of sensory prosthetic devices for motor control, and ii) to aid in the development of new, principled therapies for sensory and sensory-motor deficits following stroke.