Studies of Spatial and Temporal Integration of Differing Chromaticities by the Human Visual System

Switkes Lay摘要（0116895）“不同色度的时空整合研究”在正常的视觉环境中，空间轮廓可以通过一些刺激维度的变化来定义，例如亮度、色度、纹理、速度和深度。在过去的三十年中，早期视觉处理的研究已经描述并比较了人类视觉系统提取由这些变化定义的单个空间特征（线，边，光栅成分）的能力。视觉处理的后续步骤必须整合个体特征，以获得对形式的整体感知。这项拨款申请描述了一系列心理物理实验，这些实验研究了涉及空间、时间和色彩信息的中级视觉处理的各个方面。特征的颜色相似性或亮度对比是将物体划分为不同感知组的重要依据；然而，照明和其他因素可以在组成单个物体的元素之间呈现亮度或颜色的变化。目前的建议考虑的模式，其元素是由亮度对比或颜色对比来定义的，并研究了人类视觉系统在整合色度或亮度不同的元素特征时感知形式和运动的能力。除了分析中级时空加工的特征整合外，本实验还将探讨“第三阶段”色度加工的机制。虽然许多涉及色觉的现象可以从受体激活（第一阶段）和视网膜/LGN对抗过程（第二阶段）的角度来解释，但电生理学和心理物理学的研究都不清楚视觉皮层中颜色信息的进一步转化。本提案中的实验将测量我们检测单个特征之间的相关性的能力，无论是作为它们的不同色度的函数还是它们的平均色度。在三维色彩空间中沿不同色轴的比较性能将根据可能涉及处理色信息的第三阶段机制进行分析。本文提出了三个一般性研究：1)亮度或颜色变化定义的图案的对比度匹配性质；Ii)整合空间相关性的能力，其中单个元素的颜色/亮度对比度不同；iii)在时域内对色度不同的特征进行积分的能力。第一组研究的目标是为颜色/亮度不同的图案的感知显著性建立一个基本度量；实验涉及正弦光栅的对比度匹配。在第二组研究中，将利用点对元素内部和之间具有亮度/色度变化的平移和旋转玻璃图案来研究将局部特征整合到整体图案感知中的机制的“色盲”程度（或不色盲）。第三个领域包括探索跨色度的两种类型的时间整合的实验：视觉系统融合沿不同色轴落下的两个时间上不一致的闪光的能力，以及从时空位移过程中色度改变的点的空间和时间位移中检测运动的能力。这三项研究都是由一个问题联系在一起的：视觉系统能否整合最初由不同的第二阶段色觉机制分离的信息？该提案解决了在理解大脑机制和视觉行为之间的联系方面具有根本重要性的问题。这项工作还与PI在教育和外联方面的努力密切相关。与本提案的科学目标相关的技术、设备和结果将用于诸如国家科学基金会资助的自适应光学中心/COSMOS课程“光子、蛋白质和感知”等活动，该课程由PI组织于2001年举办；一门旨在让代表性不足的高中生接触大学科学环境的课程（http://www.chemistry.ucsc.edu/COSVIS/）。

Switkes Lay Abstract (0116895)"Studies of Spatial and Temporal Integration of Differing Chromaticities" In the normal visual environment spatial contours may be defined by variations along a number of stimulus dimensions, e.g. luminance, chromaticity, texture, velocity, and depth. During the past three decades, studies of early visual processing have characterized and compared the ability of the human visual system to extract individual spatial features (lines, edges, grating components) defined by such variations. Subsequent steps of visual processing must integrate individual features to attain the global perception of form. This grant application describes a series of psychophysical experiments which investigate aspects of this mid-level visual processing involving spatial, temporal, and chromatic information. Similarities in the color or luminance contrast of features serve as an important basis for segregating objects into differing perceptual groupings; however, lighting and other factors can render variations in luminance or color among the elements comprising an individual object. The current proposal considers patterns whose elements are defined by luminance contrast or by color contrast and investigates the ability of the human visual system to perceive form and motion when integrating elemental features differing in chromaticity or luminance. In addition to analyzing integration of features in mid-level spatiotemporal processing, the proposed experiments will also investigate the mechanisms of 'third-stage' chromatic processing. While many phenomena involving color vision can be rationalized in terms of receptor activation (first-stage) and retinal/LGN opponent processes (second-stage), both electrophysiological and psychophysical studies are unclear regarding further transformations of color information in visual cortex. Experiments in this proposal will measure our ability detect correlations among individual features both as a function of their differing chromaticities and their average chromaticities. Comparative performance along various chromatic axes in three-dimensional color space will be analyzed in terms of possible third-stage mechanisms involved in processing chromatic information. Three general studies are proposed: i) the nature of contrast matching for patterns defined by luminance or color variations; ii) the ability to integrate spatial correlations where the individual elements differ in color/luminance contrast; and iii) the ability to integrate in the time domain features which differ in chromaticity. The goal of the first set of studies is to establish a basic metric for the perceived salience of patterns differing in color/luminance; the experiments involve contrast matching of sinusoidal gratings. In the second set of studies translational and rotational Glass patterns with luminance/chromaticity variations both within and among dot-pair elements will be utilized to investigate the degree of "color-blindness" (or not) of mechanisms which integrate the local features in the perception of global patterns. The third area includes experiments probing two types of temporal integration across chromaticities: the visual system's ability to fuse two temporally noncoincident flashes which fall along differing chromatic axes and its ability to detect motion from the spatial and temporal displacement of dots whose chromaticity is altered during the spatiotemporal displacement. The three studies are linked by the question can the visual system integrate information initially segregated by differing second-stage chromatic mechanisms? The proposal addresses questions of fundamental importance in gaining an understanding of the linkage between brain mechanisms and visual behavior. The work is also closely associated with the PI's efforts in education and outreach. Techniques, equipment, and results associated with the scientific goals of this proposal will be utilized in activities such as the NSF funded Center for Adaptive Optics/COSMOS course "Photons, Proteins, and Perception" which the PI has organized for 2001; a course aimed at allowing high school students from underrepresented demographics to be exposed to a university science environment (http://www.chemistry.ucsc.edu/COSVIS/).