VISUAL MOTOR TRANSFORMATION IN CORTEX

描述(申请人提供)：向视觉目标伸手在日常生活中随处可见。这项任务看似毫不费力，但需要大量的处理才能完成。我们的目标是更好地理解视觉空间信息处理的潜在行为。为此，我们在非人类灵长类动物中使用视觉引导的触觉作为模型系统。我们的第一个目标是确定顶后区域对视觉引导到达的运动学和动力学的具体贡献。我们将使用一种新的方法来精确定位放置在整个顶内沟的可逆性注射的部位。每次注射后，我们将对动物进行一系列任务(伸展、扫视和视觉搜索)的测试，然后对失活部位进行成像。这种方法是全面的，比单一单位记录能更好地显示顶区的真实功能贡献。我们的第二个目标是确定和量化后顶叶皮质中与双手协调有关的活动成分。灵长类动物通常一起使用两只手臂来完成单只手臂难以完成或不可能完成的任务。临床证据表明，顶叶皮质在双手协调中起着作用。我们的结果将有助于区分两个具体的模型，即双手协调如何在单个神经元水平上表现出来。我们的第三个目标是量化顶后神经元在评估靶点和进行REACH决策过程中的活动，并将该活动与眼球跳动决策过程中观察到的活动进行比较。最近的研究为眼球跳动的决策提供了一个特定的模型。我们的结果将表明，对于不同类型的动作(触觉和眼跳)，目标评估和决策电路的顶脑回路是相同的还是不同的。实现这些目标将有助于我们理解感觉到运动转换、运动协调和决策的早期过程。这一结果将为制定有助于中风和其他中枢损伤恢复的合理策略以及为新一代假肢设备设计最佳大脑接口提供关键信息。公共卫生相关性这项提议的中心目标是了解视觉空间信息的早期处理，以实现视觉引导的到达。实现这一目标将有助于临床医生了解并最终扭转顶骨和枕骨中风以及其他脑创伤造成的损害。了解大脑是如何产生和代表运动计划的，对于为截肢、脊髓损伤和肌萎缩侧索硬化症等疾病患者开发有前途的神经假体也是至关重要的。

Description (provided by applicant): Reaching towards a visual target is ubiquitous in daily life. The task seems effortless, yet requires substantial processing to accomplish. Our goal is to better understand the visuospatial information processing underlying action. For this purpose, we use visually-guided reaching in the non-human primate as a model system. Our first aim is to determine the specific contributions of posterior parietal areas to the kinematics and dynamics of visually-guided reaching. We will use a novel method to precisely localize the sites of reversible injections placed throughout the intraparietal sulcus. After each injection we will test animals on a panel of tasks (reaches, saccades and visual search) and then image the site of inactivation. This method is comprehensive and better indicates the true functional contributions of parietal areas than can be achieved through single unit recording. Our second aim is to identify and quantify components of activity in posterior parietal cortex that are related to bimanual coordination. Primates commonly use the two arms together to accomplish tasks that are difficult or impossible to perform with a one arm. Clinical evidence suggests a role of the parietal cortex in bimanual coordination. Our results will help distinguish between two specific models of how bimanual coordination might be manifest at the level of individual neurons. Our third aim is to quantify the activity of posterior parietal neurons during evaluation of targets and decision-making in performing reaches, and to compare that activity to that observed during decision-making for saccadic eye movements. Recent work has suggested a specific model for decision-making for saccadic eye movements. Our results will indicate whether parietal circuits for target evaluation and decision circuits are the same or different for different kinds of action (reaches versus saccades). Achieving these aims will help us understand the early processes involved in sensory to motor transformation, motor coordination, and decision-making. The results will critically inform the devise of rational strategies for aiding recovery from strokes and other central damage, as well as the design of optimal brain interfaces for a new generation of prosthetic devices. PUBLIC HEALTH RELEVANCE The central goal of this proposal is to understand the early processing of visuospatial information for visually- guided reaching. Achieving this goal will help clinicians to understand and ultimately reverse the damage caused by parietal and occipital strokes and other brain trauma. Understanding how the brain generates and represents plans for movement is also critical to the development of promising neuroprosthetics for patients with amputations, spinal cord injuries, and disorders such as amyotrophic lateral sclerosis.