Mechanisms of Color Perception: Dependences on Color Contrast and Spatial Pattern

本研究项目涉及人类色彩感知的一个明显矛盾。当一个人类观察者被要求检测一个几乎不可见（接近阈值）的彩色目标时，他/他的视觉系统会跨空间添加颜色信号，以达到最大的灵敏度。但是，当一个人在正常可见水平（超阈值）下观看包含高度彩色物体的场景时，视觉系统似乎会减去颜色信号。在这个项目中，我们将研究这两种机制（加法和减法）如何在人类视觉皮层中结合起来产生感知。该项目对所有感知研究都具有重要意义。我们的研究结果表明，阈值感知可能与超阈值感知有很大的不同。该项目的研究结果将解释这些差异与颜色感知之间的关系。这些结果将在包括通信和工业设计在内的广泛领域具有潜在的应用。在我们的实验中，我们将使用色调和饱和度缩放技术，在从颜色阈值到高度饱和颜色的一系列锥体对比中测量人类颜色感知的空间模式依赖性。与此同时，我们将测量人类cVEP（颜色-视觉诱发电位，早期视觉皮层颜色反应的脑电图测量）对空间刺激变量的依赖性，这些变量是用头皮上密集的电极阵列记录的。cVEP实验已经证明，有两种皮层机制是阈值附近和阈值以上颜色感知的基础：单对手和双对手神经元群。继续项目中的实验旨在研究这两种机制之间的相互作用以及相互作用如何影响感知颜色。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research project concerns an apparent contradiction in human color perception. When a human observer is asked to detect a colored target that is barely visible (near threshold), her/his visual system adds color signals across space to achieve maximum sensitivity. But when one views a scene that contains highly colored objects at normal levels of visibility (suprathreshold), the visual system seems to subtract color signals. In this project, we will investigate how those two mechanisms (addition and subtraction) combine in the human visual cortex to produce perception. The project has important implications for all perceptual research. Our results indicate that perception at threshold can be very different from suprathreshold perception. The project's results will explain how these differences relate to color perception. These results will have potential applications across a wide range of areas including communication and industrial design.In our experiments, we will measure the spatial pattern dependence of color perception in humans over a range of cone contrasts from color threshold to highly saturated color, using the technique of hue and saturation scaling. In parallel, we will make measurements of the dependence on spatial stimulus variables of the human cVEP (color-Visual Evoked Potential, an EEG measure of color responses in early visual cortex) recorded with a dense array of electrodes on the scalp. The cVEP experiments have already proven that there are two cortical mechanisms that are the basis of color perception near threshold and suprathreshold: single-opponent and double-opponent neuron populations. The experiments in the continuation project are aimed at studying interactions between the two mechanisms and how interactions affect perceived color.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.