Spatial Representations and Attention

描述（由申请人提供）：人类右半球损伤经常导致单侧空间忽视和/或消失，患者无法定位，甚至可能否认左侧空间的存在。该综合征最常与右背后部病变相关。一贯地，当两个顶叶都受损（导致巴林氏综合征）时，外部空间几乎完全消失，除了在任何给定时间对一个物体的感知（同时失认症）。尽管这些损伤通常伴随着严重的空间盲，但在受影响的空间区域中呈现的刺激可以被隐式表示（即，即使在未被发现的情况下，它们也会影响表现）。一种常见的解释是，代表性完好无损，所需要的只是将其提升到某个阈值以上。这一观点受到了质疑，因为有证据表明，在这种情况下，特征没有正确地整合在一起，在自由视觉中产生了虚幻的连词。被测试的特征是那些与特定神经群相关的特征，如颜色、运动、形状和大小。然而，这些发现只测试了明确的报告。我们提出了一套心理物理研究，旨在探索特征在内隐表征中的整合程度以及这些表征的空间结构可能是什么。重点将放在因单侧中风而出现空间缺陷的患者身上。一些需要解决的问题是：在注意选择发生之前，未被发现的刺激是否被整合？内隐表征的空间结构是什么（例如，它们是三维的吗）？被忽视的刺激的特征是否有助于对被明确感知的展示的第一印象？这一发现将增强人们对视觉信息的认识，这些信息是在正常感知意识之前处理的，以及这些信息如何影响明确看到的东西。它还将增加关于视觉表征的知识，这些表征是完整的，但在视觉空间障碍中是不可用的。

DESCRIPTION (provided by applicant): Right hemisphere damage in humans often leads to unilateral spatial neglect and/or extinction, a condition in which patients do not orient to, and may even deny the existence of, the left side of space. The syndrome has been most often associated with dorsal right posterior lesions. Consistently, when both parietal lobes are damaged (causing Balint's syndrome), external space nearly disappears entirely except for the perception of one object at any given time (simultanagnosia). Despite the often severe spatial blindness that accompanies these lesions, stimuli presented in affected areas of space can be implicitly represented (i.e., they affect performance even when undetected). A common interpretation is that the representation is intact and all that is needed is a boost above some threshold. This idea had been questioned by evidence showing that features are not integrated correctly in such cases, producing illusory conjunctions in free vision. The features that were tested were those that have been associated with specialized neural populations such as color, motion, shape and size. However, these findings only tested explicit reports. We propose a set of psychophysical studies designed to explore the extent to which features are integrated in implicit representations and what the spatial structure of these representations might be. Emphasis will be on patients who have spatial deficits due to unilateral stroke. Some questions to be addressed are: Are undetected stimuli integrated before attentional selection occurs? What is the spatial structure of implicit representations (e.g., are they 3-dimensional)? Do features of neglected stimuli contribute to first impressions of displays that are explicitly perceived? The findings should enhance knowledge of visual information that is processed before awareness in normal perception as well as how this information may influence what is explicitly seen. It will also increase knowledge about visual representations that are intact but unavailable in visual spatial disorders.