CONTRAST, CONTEXT AND STIMULUS GROUPING IN STRIATE CELLS

纹状细胞中的对比度、背景和刺激分组

• 批准号: 2020221
• 负责人: TAKUJI KASAMATSU
• 金额: $ 30.79万
• 依托单位: SMITH-KETTLEWELL EYE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2020221
• 关键词: behavioral /social science research tag; cats; form /pattern perception; microelectrodes; neural information processing; neurophysiology; single cell analysis; space perception; visual cortex; visual depth perception; visual perception; visual stimulus

Gestalt perceptual theory says that the visual system groups features together on the basis of similarity, proximity, smoothness and closure. Recent psychophysical and neurophysiolgical studies have found evidence of spatial facilitation and suppression that appears to conform to the perceptual grouping rules. The perceptual grouping may be implemented by long-range lateral connections in visual cortex. Recently, we found that single-cell responses to a central target were modulated by collinear flanking objects. This modulation was dependent on the cell's contrast threshold for the central target. We hypothesized that the lateral interactions in area 17 are arranged into two antagonistic mechanisms: 1) Facilitation is spatially organized along the optimal orientation of the cell in a collinear manner; 2) Suppression is non-selective for orientation or spatial frequency, and is distributed diffusely around the cell's response field. The balance between these two mechanisms, dictated by the cell's contrast threshold, controls the cells firing. Based on this hypothesis, we will study the following four questions by physiological recording of single cells from the visual cortex of anesthetized and paralyzed preparations. Aim l will answer the question whether the context-dependent modulation of cellular responses depends on contrast relative to the cell's contrast threshold, rather than on the physical contrast of the stimulus. We want to know how general the contrast threshold-dependent facilitation and suppression is. Aim 2 will dissect the spatial organization of the modulatory interactions. In particular, we will elucidate an organizational principle along the optimal orientation of the cell under study. Aim 3 will study effects of distance between target and flanks, flanks size, and their spatial frequency on the modulatory interactions. This aim is focused on an issue of similarity and closeness of target and flanks. Aim 4 will extend our search of the neural basis of perceptual grouping one step ahead, using compound stimuli made of many elements in curve. We will answer whether single cells respond differently when the optimally positioned test stimulus is a part of a smoothly curved path or circle composed of many of the same patterns as the test patch.

格式塔知觉理论认为视觉系统具有以下特征： 在相似性、接近性、平滑性和封闭性的基础上结合在一起。 最近的心理物理学和神经生理学研究发现了证据 空间促进和抑制似乎符合 感知分组规则。感知分组可以通过以下方式实现 视觉皮层的长距离横向连接。最近，我们发现 单细胞对中心目标的反应由共线调节 侧翼物体。这种调节取决于细胞的对比度 中心目标的阈值。我们假设横向 17区的相互作用分为两种对立机制： 1）促进是沿着最佳方向进行空间组织的 单元以共线方式； 2) 抑制是非选择性的 方向或空间频率，并且分散地分布在 细胞的反应场。这两种机制之间的平衡，决定了 通过细胞的对比度阈值，控制细胞放电。基于 根据这个假设，我们将研究以下四个问题： 视觉皮层单细胞的生理记录 麻醉和麻痹制剂。 目标 l 将回答上下文相关调制是否 细胞反应的程度取决于相对于细胞对比度的对比度 阈值，而不是刺激的物理对比度。我们想要 了解对比度阈值依赖性促进有多普遍 抑制群岛 目标 2 将剖析调制的空间组织 互动。 特别是，我们将阐明一个组织 沿着所研究细胞的最佳方向的原则。 目标 3 将研究目标与侧翼、侧翼之间距离的影响 大小及其空间频率对调制相互作用的影响。这 目标重点关注目标和目标的相似性和接近性问题 侧翼。 目标 4 将扩展我们对知觉分组的神经基础的研究 领先一步，使用由曲线中的许多元素组成的复合刺激。我们 将回答单细胞在最佳条件下是否有不同的反应 定位测试刺激是平滑弯曲路径或圆圈的一部分 由许多与测试补丁相同的图案组成。