Object, face, body and scene representations in the human brain

人脑中的物体、面部、身体和场景表征

• 批准号: 10008851
• 负责人: Christopher Baker
• 金额: $ 151.98万
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10008851
• 关键词: Anterior; Behavioral; Body part; Brain; Brain imaging; Brain region; Categories; Cognition; Cognitive; Complex; Computers; Consensus; Data; Event; Eye; Face; Face Processing; Functional Magnetic Resonance Imaging; Goals; Hand; Human; Image; Judgment; Knowledge; Learning; Leg; Light; Magnetoencephalography; Measures; Medial; Memory; Mental Health; Nature; Parietal Lobe; Participant; Pattern; Perception; Research; Resolution; Retina; Role; Series; Social Behavior; Stimulus; Structure; Time; Visual; Visual Cortex; base; behavior measurement; behavioral response; cognitive process; experience; falls; foot; imaging properties; insight; interest; memory recall; nervous system disorder; pet animal; recruit; response; visual stimulus

The goal of this research is to understand how we see what we see: how does the brain analyze the light falling on the retina of the eye to reveal a world full of objects, people and things? During the past year we have focused on both (i) perception and (ii) memory of complex visual stimuli, in particular real-world visual scenes, objects and people (NCT00001360). Perception: Real-world scenes are incredibly complex and heterogeneous, yet we are able to categorize them and identify objects and people within those scenes effortlessly. While prior studies have identified brain regions that appear to be specialized for processing faces, object and scenes, it remains unclear what the precise roles of these different regions are and what information they contain. We presented participants with 144 real-world scenes representing a wide range of object (e.g. bags, pets) and scene (e.g. beach, mountain) categories. First, we presented those scenes to participants while we measured their brain activity using functional magnetic resonance imaging (fMRI). Based on the patterns of responses observed in different brain regions, we determined how each region represents the scenes and how the structure of those representations differs across regions. Second, we asked participants to arrange the 144 images on a large computer screen according to their similarity, with similar scenes placed close together and very different scenes placed far apart. This gave us a measure of the conceptual understanding of the scenes. We then compared the brain and behavioral data to determine which brain regions underlie our conceptual understanding. Surprisingly, we found only a limited correspondence between the behavioral and brain data. These results suggest a complex relationship between localized responses in high-level visual cortex and behavioral similarity judgments each domain reflects different properties of the images, and responses in high-level visual cortex may correspond to intermediate stages of processing between basic visual features and the conceptual categories that dominate the behavioral response. These results provide important insights into the brain mechanisms supporting our understanding of objects and scenes. However, this study focused on a relatively small number of object and scene categories. We are now substantially extending this study by collecting behavioral, fMRI and magnetoencephalography (MEG) data for nearly two thousand categories of objects that span our everyday experience. Memory: To understand the nature of object and scene memory, we have focused on two specific issues: 1) Organization of the medial parietal cortex Human medial parietal cortex (MPC) has been implicated in multiple cognitive processes including memory recall, visual scene processing and navigation. Given such diverse recruitment of MPC across cognitive domains historically considered largely independent, it is not surprising that there has been no clear consensus with regard to its function and overarching organization. In a series of studies, we measured brain activations with fMRI while we presented participants with images of scenes and people and also asked them to recall specific events (e.g. shaving, going to a beach) as well as recall famous or personally familiar places and people. Our findings revealed two key insights. First, we found an apparent gradient of representation from more perceptually related to more memory related from posterior to anterior within MPC. Second, we found distinct subdivisions within MPC that were active differentially during recall of either people or places. Collectively, these results provide a new framework for understanding the functional role of MPC and its significance during different aspects of cognition. 2) Elucidating the content of scene memory When we recall a previously experienced event, what exactly are we remembering? Are our memories a precise, high-definition recording of that event, a low-resolution gist of that memory, or even just a verbal description of what we saw? Answering this question is an essential component of being able to tease apart the mechanisms of memory: what information is encoded and maintained, how memory decays over time, and what information is retrieved from these memories. In this study, we investigated the content of memory for real world scenes using a drawing task. Participants studied 30 scenes and, after 10 minutes, drew as many images in as much detail as possible from memory. The resulting memory-based drawings were scored by thousands of online observers, revealing numerous objects, few memory intrusions, and precise spatial information. Our findings show that not only is it possible to quantify the content of memory during free recall, but those memories contain detailed representations of our visual experiences. Elucidating how the brain enables us to recognize objects, scenes, faces and bodies provides important insights into the nature of our internal representations of the world around us. Understanding these representations is vital in trying to determine the underlying deficits in many mental health and neurological disorders.

这项研究的目的是了解我们如何看待我们看到的内容：大脑如何分析眼睛视网膜上的光线以揭示一个充满物体，人和事物的世界？ 在过去的一年中，我们专注于（i）感知和（ii）复杂的视觉刺激的记忆，特别是现实世界的视觉场景，对象和人（NCT00001360）。 洞察力： 现实世界的场景非常复杂和异质，但是我们能够毫不费力地对它们进行分类，并毫不费力地识别对象和人。虽然先前的研究已经确定了似乎专门用于处理面孔，对象和场景的大脑区域，但仍不清楚这些不同区域的确切作用以及它们所包含的信息。 我们向参与者展示了144个现实世界的场景，这些场景代表了广泛的物体（例如袋子，宠物）和场景（例如海滩，山区）类别。首先，我们使用功能磁共振成像（fMRI）测量了他们的大脑活动，向参与者介绍了这些场景。基于在不同大脑区域观察到的响应模式，我们确定了每个区域如何表示场景以及这些表示的结构如何在各个区域之间有所不同。其次，我们要求参与者根据他们的相似性在大型计算机屏幕上安排144张图像，相似的场景靠近在一起，并且将不同的场景放置在很远的地方。这为我们提供了对场景的概念理解的衡量标准。然后，我们比较了大脑和行为数据，以确定哪些大脑区域是我们的概念理解的基础。令人惊讶的是，我们发现行为和大脑数据之间的对应关系有限。这些结果表明，高级视觉皮层中的局部响应与行为相似性判断之间存在复杂的关系。每个域都反映了图像的不同属性，而高级视觉皮层中的响应可能对应于基本视觉特征与概念性类别之间的中间阶段，这些阶段占据了行为响应。 这些结果为支持我们对物体和场景的理解的大脑机制提供了重要的见解。但是，这项研究的重点是相对较少的对象和场景类别。现在，我们通过收集行为，fMRI和磁脑电图（MEG）数据来大大扩展这项研究，以跨越我们日常体验的近2000种类别的对象。 记忆： 为了了解对象和场景记忆的性质，我们专注于两个特定问题： 1）内侧顶叶的组织 人体内侧顶叶皮层（MPC）与多个认知过程有关，包括记忆回忆，视觉场景处理和导航。鉴于历史上认为MPC如此多样化的MPC在很大程度上被认为是独立的，因此在其功能和总体组织方面没有明确的共识也就不足为奇了。在一系列研究中，我们通过fMRI测量了大脑的激活，同时我们向参与者展示了场景和人的图像，还要求他们回忆起特定的事件（例如剃须，去海滩），并召回了著名或个人熟悉的地方和个人。我们的发现揭示了两个关键见解。首先，我们发现了从更感知上与MPC后部到前部相关的更多记忆相关的表示的明显梯度。其次，我们发现MPC内部不同的细分在召回人或地点期间都在差异上活跃。总的来说，这些结果为理解MPC的功能作用及其在认知不同方面的意义提供了一个新的框架。 2）阐明场景内存的内容 当我们回想起以前经验丰富的活动时，我们到底记得什么？我们的记忆是该事件的精确，高清记录，该记忆的低分辨率要点，甚至只是对我们所看到的言语描述？回答这个问题是能够嘲笑内存机制的重要组成部分：编码和维护哪些信息，随着时间的推移的记忆衰减以及从这些记忆中检索到哪些信息。在这项研究中，我们使用绘图任务研究了现实世界场景的记忆内容。参与者研究了30个场景，10分钟后，从内存中绘制了尽可能多的详细信息。由此产生的基于内存的图纸由成千上万的在线观察者评分，揭示了许多对象，很少的记忆入侵和精确的空间信息。我们的发现表明，不仅可以在免费回忆期间量化内存内容，而且这些记忆包含我们视觉体验的详细表示。 阐明大脑如何使我们能够识别对象，场景，面部和身体，为我们周围世界内部表现的本质提供了重要的见解。理解这些表征对于试图确定许多心理健康和神经系统疾病的潜在缺陷至关重要。