MECHANISMS OF BRIGHTNESS PERCEPTION AND FILLING-IN

描述：在过去的三十年里，对视觉处理的研究 揭示了神经元通常最好由亮度模式驱动， 对比度而不是亮度本身。从主要视力进展 皮层到许多视觉区域，延伸到顶骨， 颞叶，最佳刺激往往涉及更复杂的 随着感受野尺寸的增加，亮度对比度的排列。 视觉神经元对亮度对比模式的反应 这表明我们通过一个区域的活动模式来观察视觉形式。 许多神经元对亮度对比的模式敏感。一个伟大 我们是如何看到形体以外的东西的 具体地说，物体的表面特性，如它们的 亮度、颜色和纹理。大量的心理物理学 实验表明，这些表面的感知 属性强烈依赖于亮度信息， 色边界然而，大脑表面的神经过程 计算的属性几乎完全未知。研究 在这个应用程序中提出的目的是揭示这些过程，通过集中 关于亮度感知。这项研究的长期目标是 了解视觉皮层神经元的反应方式， 相互作用，产生视觉感知。为了实现这一目标， 传统上用于心理物理学实验的刺激用于 检查视觉神经元对表面特性的反应。的 亮度信息的表示将在 皮质区V1和V2以及LGN和视束。录音 在这些网站上的每一个将建立在什么阶段的视觉 处理与亮度相关的神经活动起源。 细胞色素氧化酶染色将用于确定是否亮度 相关的神经活动仅限于特定的隔室， V1和V2被认为是并行处理流的组成部分。通过 测量对各种均匀模式的响应的时间过程， 照明，假设将被测试，有不同的快速 和大脑皮层计算亮度的慢成分。通过 采用一系列从知觉研究中借来的视觉刺激， 将确定是否有神经元以一种 与亮度相关，与刺激类型无关。

DESCRIPTION: Research on visual processing in the past thirty years has revealed that neurons are usually best driven by patterns of luminance contrast rather than luminance itself. Progressing from primary visual cortex to the numerous visual areas that stretch toward the parietal and temporal lobes, optimal stimuli tend to involve more complex arrangements of luminance contrast as receptive fields increase in size. The responses of visual neurons to patterns of luminance contrast suggest that we see visual form by the pattern of activity across a great many neurons sensitive to patterns of luminance contrast. A great mystery that remains is how we see anything other than form, specifically, the surface properties of objects such as their brightness, color, and texture. A large number of psychophysical experiments have demonstrated that the perception of these surface attributes is strongly dependent on information at luminance and chromatic boundaries. However, the neural processes by which the surface properties are computed are almost entirely unknown. The research proposed in this application aims to uncover these processes by focusing on brightness perception. The long-term goal of this research is to understand the manner in which neurons in visual cortex respond and interact, giving rise to visual perception. To achieve this goal, stimuli traditionally used in psychophysical experiments are used to examine the responses of visual neurons to surface properties. The representation of brightness information will be investigated in cortical areas V1 and V2 as well as the LGN and optic tract. Recordings made at each of these sites will establish at what stage in visual processing neural activity correlated with brightness originates. Cytochrome oxidase staining will be used to determine whether brightness associated neural activity is restricted to particular compartments of V1 and V2 thought to be components of parallel processing streams. By measuring the time course of responses to various patterns of uniform illumination, the hypothesis will be tested that there are distinct fast and slow components in the cortical computation of brightness. By employing a range of visual stimuli borrowed from perceptual studies, it will be established whether there are neurons that fire in a manner correlated with brightness irrespective of the type of stimulus.