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

这项研究项目涉及人类颜色知觉中的一个明显的矛盾。当人类观察者被要求检测一个几乎看不见(接近阈值)的有色目标时，她/他的视觉系统会在空间中添加颜色信号，以实现最大的灵敏度。但是，当一个人在正常能见度水平(高于阈值)下观看包含高颜色物体的场景时，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)如何在人类视皮层中结合起来产生知觉。该项目对所有感性研究都有重要的影响。我们的结果表明，阈值知觉与阈值以上知觉有很大的不同。该项目的结果将解释这些差异与颜色感知的关系。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，在从颜色阈值到高饱和度的一系列锥形对比度上测量人类颜色知觉的空间模式依赖性。同时，我们将测量用头皮上密集的电极阵列记录的人类cVEP(彩色视觉诱发电位，早期视觉皮质颜色反应的脑电测量)对空间刺激变量的依赖性。CVEP实验已经证明，存在两种皮层机制，它们是阈值附近和阈值上颜色感知的基础：单对手神经元群体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的颜色。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.