Symmetry as a cue to object and scene representations in human visual cortex

对称性作为人类视觉皮层中物体和场景表征的线索

• 批准号: RGPIN-2020-06104
• 负责人: Kohler, Peter
• 金额: $ 1.75万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=764061
• 关键词: Symmetry; cue; object; scene; representations

The human visual system must convert the 2D image arriving at the retina into a 3D representation of the visual scene that we can use to perceive and interact with the world. Visual symmetry is an important cue to this process and has been found to elicit strong responses in visually responsive brain areas. Most studies of symmetry in the context of visual perception have used a limited range of stimulus parameters: (1) Reflection rather than other types of symmetry, (2) symmetry axes at a single image location, and (3) symmetries in the fronto-parallel image plane. The proposed research program builds on recent advances in order to address these limitations and enhance our understanding of symmetry as a cue to object and scene perception. Project 1 will explore how sensitivity to symmetry is modulated by symmetry type, tiling and skew. My prior work shows that visual brain areas are sensitive to symmetries other than reflection, and that textures in which symmetries are tiled across the plane produce robust visual responses, but it is unclear how tiling and symmetry type modulate activity across brain areas. The skew manipulation is motivated by the fact that although symmetries commonly occur in the natural world, symmetrical image-plane projections onto the retina rarely occur under natural viewing. It is thus natural to ask to what extent the visual system can overcome distortions introduced when symmetries in the world produce "skewed" projections onto the retina. To address the hypothesis that these manipulations differentially drive distinct symmetry-sensitive sub-networks in human visual cortex, I will use brain imaging methods to measure the amplitude, timing and cortical sources of responses to symmetry with high temporal and spatial precision. This project will provide a more complete characterization of symmetry tuning in the visual system and has the potential to connect distinct branches of the literature. Project 2 will address the hypothesis that sensitivity to symmetry is the result of learning as infants and young children are exposed to symmetries in their visual environment, and that responses to symmetry in human visual cortex should therefore change over early development. I will test this by comparing symmetry responses in infants and adults. To our knowledge, this will be the first brain imaging study to investigate symmetry perception in infants or young children. This study will reveal any sensitivity to symmetry that may exist in early visual development, and provide cues as to how encoding of symmetry changes with exposure to the natural world. This research program addresses an important gap between the symmetry and 3D object and scene perception literatures using well-controlled stimuli combined with state-of-the-art brain imaging techniques. The findings have the potential to deepen our understanding of the role of symmetry in natural vision, and inform related research in visual neuroscience and computer vision.

人类视觉系统必须将到达视网膜的 2D 图像转换为视觉场景的 3D 表示，我们可以用它来感知世界并与世界互动。视觉对称性是这一过程的重要线索，并且被发现可以在视觉敏感的大脑区域中引起强烈的反应。大多数视觉感知背景下的对称性研究都使用了有限范围的刺激参数：（1）反射而不是其他类型的对称性，（2）单个图像位置的对称轴，以及（3）额叶的对称性平行图像平面。拟议的研究计划建立在最新进展的基础上，旨在解决这些限制并增强我们对对称性作为物体和场景感知线索的理解。项目 1 将探索如何通过对称类型、平铺和倾斜来调节对对称性的敏感度。我之前的工作表明，视觉大脑区域对反射以外的对称性很敏感，并且对称性平铺在平面上的纹理会产生强烈的视觉反应，但尚不清楚平铺和对称类型如何调节大脑区域的活动。倾斜操纵的动机是，尽管对称性在自然界中普遍存在，但在自然观看下很少出现在视网膜上的对称图像平面投影。因此，很自然地要问，当世界的对称性在视网膜上产生“倾斜”投影时，视觉系统可以在多大程度上克服所引入的扭曲。为了解决这些操作不同地驱动人类视觉皮层中不同的对称敏感子网络的假设，我将使用大脑成像方法以高时间和空间精度测量对称性反应的幅度、时间和皮层来源。该项目将提供视觉系统中对称性调谐的更完整的表征，并有可能连接文献的不同分支。项目 2 将提出这样的假设：对对称的敏感性是婴儿和幼儿在视觉环境中接触对称性时学习的结果，因此，人类视觉皮层对对称性的反应应该在早期发育过程中发生变化。我将通过比较婴儿和成人的对称反应来测试这一点。据我们所知，这将是第一个研究婴儿或幼儿对称知觉的脑成像研究。这项研究将揭示早期视觉发育中可能存在的对对称性的敏感性，并提供有关对称性编码如何随着接触自然世界而变化的线索。该研究项目利用良好控制的刺激与最先进的脑成像技术相结合，解决了对称性与 3D 物体和场景感知文献之间的重要差距。这些发现有可能加深我们对对称性在自然视觉中的作用的理解，并为视觉神经科学和计算机视觉的相关研究提供信息。