The representation and processing of contour and surface in the human brain

人脑中轮廓和表面的表示和处理

• 批准号: BB/P007252/1
• 负责人: Antony Morland
• 金额: $ 57.21万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FP007252%2F1
• 关键词: representation; processing; contour; surface; human

The visual brain has been interrogated with functional magnetic resonance imaging (fMRI) over the last twenty years, providing significant insight into its organisation. Earlier processing occurs in posterior, 'lower-level' visual brain areas, which contain explicit visual field maps. Such areas are 'mapped' by using visual stimuli that systematically move through the visual field, whilst recording the brain responses. Improvements in techniques have allowed an increasing extent of the visual brain to be mapped in this manner. An alternative method to chart the visual brain's organisation is to test for stimulus selectivity, typically by contrasting the brain's responses to two or more discrete stimulus categories. This approach has identified 'higher-level' category selective areas, for example a shape-selective region referred to as the lateral occipital complex.It was first thought that category selective regions had little or no explicit mapping of the visual field. However, as more visual field maps were discovered some were found to overlap with category selective regions, implying that the two organizations are not mutually exclusive. We will refer to these overlapping regions as 'mid-level' visual field maps. The fact that the two organizing principles intersect gives us an opportunity to understand how the visual brain transitions from low-to-high level processing. Such transitional points should yield valuable insights into the representation of 'abstract' information in higher-level areas.Despite their potential importance, little research on these mid-level regions exists. We aim to address this by focusing on understanding the roles 'mid-level' visual areas play. We have published evidence that mid-level areas can represent abstract information, but the nature of the information represented at this level and the nature of the representations themselves remain unknown. Our overarching aim, therefore, is to find out what visual information is processed and how it represented at this mid-level of the visual system.The mid-level visual areas we will focus on cluster in lateral occipital cortex. At the same time we will also assess visual field maps that lie in dorsal and ventral occipital cortex, to verify that any effects we measure are dissociable. Reassuringly, using this strategy we have already found that certain abstract representations are found in lateral, but not ventral or dorsal mid-level areas. We anticipate therefore that our work will again exhibit dissociable effects in mid-level areas.Our work implies that lateral occipital areas process aspects of contour curvature; we aim to further refine our understanding of these representations. We already have pilot data on some aspects of contour processing and believe therefore that much of the proposed work has a high chance of success. At the same time however we want to explore the processing and representation of 3D surface curvature, to determine whether such properties have shared or unique neural underpinnings. This work is higher risk, but its return could be large as it represents the first opportunity to bring together the study of contour and surface and learn how their relative contributions to our perception of objects is achieved in the human brain.We will combine perceptual measurements and fMRI to reveal how the human brain processes and represents contour and surface curvature. The perceptual experiments will reveal how our stimulus manipulations are perceived; determining which stimuli will be presented during neuroimaging experiments. Both approaches will leverage our expertise in stimulus control, which is grounded in computational methods that can generalize from contour to surface. Further, we have demonstrated that we can characterize our stimuli with perceptual and physical metrics that explain patterns of response in mid-level visual areas and this approach will be extended in the proposed work.

在过去的二十年里，功能磁共振成像（fMRI）对视觉大脑进行了研究，为其组织提供了重要的见解。早期的加工发生在大脑后部的“较低水平”视觉区域，该区域包含明确的视野地图。这些区域是通过使用视觉刺激系统地在视野中移动来“绘制”的，同时记录大脑的反应。技术的进步使得以这种方式绘制视觉大脑的范围越来越大。另一种绘制视觉大脑组织的方法是测试刺激选择性，通常是通过对比大脑对两种或两种以上离散刺激类别的反应。这种方法已经确定了“更高级别”的类别选择区域，例如称为外侧枕复合体的形状选择区域。人们最初认为，类别选择区域很少或没有明确的视野映射。然而，随着越来越多的视野地图被发现，有些地图与类别选择区域重叠，这意味着这两个组织并非相互排斥。我们将这些重叠的区域称为“中层”视野图。事实上，这两种组织原则相互交叉，让我们有机会了解视觉大脑是如何从低水平处理过渡到高水平处理的。这样的过渡点应该产生对高级领域中“抽象”信息表示的有价值的见解。尽管它们具有潜在的重要性，但对这些中层地区的研究却很少。我们的目标是通过理解“中级”视觉区域所扮演的角色来解决这个问题。我们发表的证据表明，中层区域可以表示抽象信息，但在这一层次上表示的信息的性质和表示本身的性质仍然未知。因此，我们的首要目标是找出哪些视觉信息是被处理的，以及它是如何在视觉系统的中层表现出来的。我们将重点关注的中级视觉区集中在枕侧皮层。同时，我们还将评估位于枕叶皮层背侧和腹侧的视野图，以验证我们测量的任何影响都是可分离的。令人欣慰的是，使用这种策略，我们已经发现某些抽象表征存在于外侧，而不是腹侧或背侧中层区域。因此，我们预计我们的工作将再次在中层区域表现出可解离效应。我们的工作表明枕侧区处理轮廓曲率的各个方面；我们的目标是进一步完善我们对这些表征的理解。我们已经在轮廓处理的某些方面获得了试点数据，因此我们相信，大部分提出的工作都有很高的成功机会。与此同时，我们想要探索三维曲面曲率的处理和表示，以确定这些属性是否具有共享或独特的神经基础。这项工作的风险更高，但它的回报可能很大，因为它代表了第一次将轮廓和表面的研究结合在一起的机会，并了解它们对我们对物体的感知是如何在人脑中实现的。我们将结合感知测量和功能磁共振成像来揭示人类大脑如何处理和表示轮廓和表面曲率。知觉实验将揭示我们的刺激操作是如何被感知的；决定哪些刺激将在神经成像实验中呈现。这两种方法都将利用我们在刺激控制方面的专业知识，这是基于可以从轮廓推广到表面的计算方法。此外，我们已经证明，我们可以用知觉和物理指标来描述我们的刺激，这些指标可以解释中级视觉区域的反应模式，这种方法将在拟议的工作中得到扩展。

项目成果

A Direct Demonstration of Functional Differences between Subdivisions of Human V5/MT.

• DOI: 10.1093/cercor/bhw362
• 发表时间: 2017-01-01
• 期刊: Cerebral cortex (New York, N.Y. : 1991)
• 作者: Strong SL;Silson EH;Gouws AD;Morland AB;McKeefry DJ
• 通讯作者: McKeefry DJ

An enhanced role for right hV5/MT+ in the analysis of motion in the contra- and ipsi-lateral visual hemi-fields.

右 hV5/MT 在对侧和同侧视觉半视野运动分析中的作用增强。

• DOI: 10.1016/j.bbr.2019.112060
• 发表时间: 2019
• 期刊: Behavioural brain research
• 影响因子: 2.7
• 作者: Strong SL

Asymmetries between achromatic and chromatic extraction of 3D motion signals.

3D 运动信号的消色差和彩色提取之间的不对称。

• DOI: 10.1073/pnas.1817202116
• 发表时间: 2019
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Kaestner M

The emergence of tuning to global shape properties of radial frequency patterns in the ventral visual pathway

腹侧视觉通路中径向频率模式的全局形状特性调谐的出现

• DOI: 10.1101/2023.03.01.530430
• 发表时间: 2023
• 作者: Lawrence S

Radial frequency tuning in human visual cortex

人类视觉皮层的径向频率调谐

• DOI: 10.1167/17.10.293
• 发表时间: 2017
• 期刊: Journal of Vision
• 影响因子: 1.8
• 作者: Morland A