Place Representations in the Human Visual System

我们是移动的生物，这一事实对我们的存在来说， 穿越太空几乎所有的行为对我们的生存都是必不可少的--寻找食物，寻找配偶， 躲避掠食者-需要在外部世界中导航。半个世纪的研究表明， 人类和动物使用世界大尺度空间结构的认知“地图”来促进这一点 能力用于形成这些地图的大部分信息最初是从视觉中获取的。但这是一个 难题：我们如何将最初从特定视图和特定视图中获取的视觉空间信息 实例转换为可用于导航的环境空间的视点不变表示 计划？这里提出的研究将使用功能性磁共振成像（fMRI）来解决 这个问题在以前工作的基础上，我们假设人类大脑至少支持三种 空间表示的不同层次：（1）它表示对象和表面的位置 相对于各种身体部位，如眼睛和手（身体空间）;（2）它代表了关系 在身体的躯干和锚定在一组固定表面上的坐标框架之间， 定义了局部场景（场景空间）;（3）它代表了观察者的位置和方向， 更大的环境，包括相对于当前“在地平线上”的位置（世界空间）。 拟议研究的第一部分将检查海马旁和海马后区的场景空间表征， 特别强调揭示这些机制， 表示是从经验中学习的，并且随着时间的推移而改变。第二部分建议 研究将检查参与代表身体空间的神经机制， 将这些机制与那些涉及表示场景空间的机制区分开来。第三部分 拟议中的研究将检查参与表征世界空间的神经机制。虽然这 研究并没有检查盲人的空间处理，所获得的结果将有助于我们 与愿景紧密相连的过程和相对非模式的过程之间存在着冲突。作为 因此，这些知识对于盲人康复策略的制定至关重要。

There are few circumstances more fundamental to our existence in the fact that we are creatures that move through space. Almost all of the behaviors are essential to our survival - locating food, finding a mate, and avoiding predators - require navigation through the external world. A half-century of research suggests that humans and animals use cognitive "maps" of the large-scale spatial structure of the world to facilitate this ability. Much of the information used to form these maps is initially acquired from vision. But this presents a puzzle: how do we transform visuospatial information initially acquired from specific views and specific instances into a viewpoint-invariant representation of environmental space that can be used for navigational planning? The research proposed here will use functional magnetic resonance imaging (fMRI) to address this question. On the basis of previous work, we hypothesize that the human brain supports at least three distinct hierarchical levels of spatial representation: (1) it represents the locations of objects and surfaces relative to various body parts such as the eye and hand (body-space); (2) it represents the relationship between the trunk of the body and a coordinate frame anchored on the set of immovable surfaces that defines the local scene (scene-space); (3) it represents the the location and orientation of the observer within the larger environment, including relative to locations that are currently "over the horizon" (world-space). The first part of the proposed research will examine scene-space representations in parahippocampal and retrosplenial cortices with particular emphasis on uncovering the mechanisms by which these representations are learned from experience and change over time. The second part of the proposed research will examine the neural mechanisms involved in representing body-space and will functionally distinguish these mechanisms from those involved in representing scene-space. The third part of the proposed research will examine the neural mechanisms involved in representing world-space. Although this research does not examine spatial processing in nonsighted individuals, the results obtained will help us to distinguislvbetween processes that are inextricably tied to vision and those that are relatively amodal. As such, this knowledge could be critical for development of rehabilitation strategies in the blind.