The Role of Extrastriate and Parietal Cortex in the Control of Steering

描述(由申请人提供)：本项目的主要目的是了解包括人类在内的灵长类动物利用视觉运动信息导航的感知和生理机制。以前的工作已经阐明了模拟自我运动的被动感知的机制，但这与实际使用运动信息来指导正在进行的轨迹相去甚远。视觉导航有两个主要的线索：目标(和障碍物)的位置和提供关于一个人在这个世界上的即时轨迹的即时反馈的“光流”信息。这项提议中的实验将测试高级视觉皮质中的运动敏感神经元如何处理、组合和代表这两个线索，以指导正在进行的行为。生理学实验将针对纹外背侧皮质最高水平的两个区域：内侧上颞区(MST)和腹侧顶内区(VIP)。我们将测试这些区域的信号如何与最近开发的主动转向任务的性能相关。在这项任务中，非人灵长类动物控制着虚拟现实环境中呈现的虚拟轨迹。这使得对线索的精确控制，并使构成该提案核心的生理实验成为可能。在AIMS 1和AIMS 2的生理实验中测试的特定假设涉及这些信号支持复杂的自然任务的执行的机制。在目标3中，我们将开发一个生物上真实的、受实验限制的神经系统如何控制转向行为的计算模型。这些目标的成功达成将使我们能够理解这种指导在大脑中的哪里得到支持，以及那里的信号如何与行为能力相关。从纯粹的科学角度来看，这些信息很重要，也可能有助于创造视觉假体来帮助视障患者导航，并可能有助于改进的机器人导航系统的开发。

DESCRIPTION (provided by applicant): The principal aims of this project are to understand the perceptual and physiological mechanisms that allow primates, including man, to navigate using visual motion information. Previous work has elucidated the mechanisms of the passive perception of simulated self-motion, but this is a far cry from actually using motion information t guide an ongoing trajectory. There are two primary cues used in visual navigation: the position of targets (and obstacles) and the "optic flow" information that provides instantaneous feedback about one's immediate trajectory in the world. The experiments in this proposal wil test how motion-sensitive neurons in the higher levels of visual cortex process, combine, and represent these two cues for the guidance of ongoing behavior. The physiological experiments will be directed at two areas at the highest levels of the "motion system" in dorsal extrastriate cortex: the medial superior temporal area (MST) and the ventral intraparietal area (VIP). We will test how the signals in these areas correlate with performance on a recently developed active steering task. In this task, nonhuman primates control a virtual trajectory presented in a virtual reality setting. This allows precise control of the cues and also enables the physiological experiments that form the core of the proposal. The specific hypotheses under test in the physiological experiments in Aims 1 and 2 concern the mechanisms by which these signals support performance of a complex, natural task. In Aim 3, we will be developing a biologically realistic, experimentally-constrained computational model of how the nervous system controls steering behavior. Successful conclusion of these aims will allow us to understand both where in the brain such guidance is supported, and how the signals there relate to behavioral capabilities. This information is important from a pure scientific perspective, and will also potentially inform the creation of visual prosthetics to assist navigation by visually impaired patients, and could help the development of improved robotic navigation systems.