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

这个研究项目涉及人类颜色感知中的一个明显矛盾。当人类观察者被要求检测一个几乎不可见的彩色目标（接近阈值）时，她/他的视觉系统会在空间中添加颜色信号，以达到最大的灵敏度。但是，当一个人在正常可见度（阈上）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联合收割机产生感知。该项目对所有知觉研究都有重要意义。我们的研究结果表明，在阈值的知觉可以是非常不同的阈上知觉。该项目的结果将解释这些差异如何与颜色感知有关。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前景。在我们的实验中，我们将使用色调和饱和度缩放技术，测量从颜色阈值到高度饱和颜色的锥对比度范围内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EEG测量）的空间刺激变量的依赖性，这些变量是用头皮上的密集电极阵列记录的。cVEP实验已经证明，有两种皮层机制是阈值附近和阈上颜色感知的基础：单对手和双对手神经元群体。延续项目中的实验旨在研究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NSF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而被认为值得支持。

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.