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到我们所看到的：大脑如何分析落在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？ 在过去的一年里，我们专注于（i）感知和（ii）复杂视觉刺激的记忆，特别是现实世界的视觉场景，物体和人（NCT 00001360）。 感知： 现实世界的场景是非常复杂和异构的，但我们能够对它们进行分类，并毫不费力地识别这些场景中的对象和人。虽然先前的研究已经确定了似乎专门用于处理面部，物体和场景的大脑区域，但仍不清楚这些不同区域的确切作用以及它们包含的信息。 我们向参与者展示了144个真实世界的场景，这些场景代表了各种各样的对象（例如包、宠物）和场景（例如海滩、山脉）类别。首先，我们向参与者展示这些场景，同时使用功能性磁共振成像（fMRI）测量他们的大脑活动。根据在不同大脑区域观察到的反应模式，我们确定了每个区域如何表示场景，以及这些表示的结构在不同区域之间有何不同。其次，我们要求参与者在一个大的电脑屏幕上根据它们的相似性排列144张图像，相似的场景放在一起，非常不同的场景放在远处。这给了我们对场景的概念性理解的一个衡量标准。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只有有限的对应关系。这些结果表明，在高层次的视觉皮层的本地化反应和行为相似性判断之间的复杂关系，每个域反映了不同的属性的图像，在高层次的视觉皮层的反应可能对应于中间阶段的基本视觉特征和概念类别之间的处理，主导的行为反应。 这些结果为我们理解物体和场景的大脑机制提供了重要的见解。然而，这项研究集中在相对较少的对象和场景类别。我们现在正在通过收集行为，功能磁共振成像和脑磁图（MEG）数据来扩展这项研究，这些数据涉及我们日常经验中的近2000种对象。 内存： 为了理解对象和场景记忆的本质，我们关注了两个具体问题： 1)内侧顶叶皮质的组织 人类内侧顶叶皮层（MPC）参与了多种认知过程，包括记忆回忆、视觉场景处理和导航。鉴于MPC在历史上被认为是独立的认知领域中的多样性招聘，关于其功能和总体组织没有明确的共识也就不足为奇了。在一系列的研究中，我们用功能磁共振成像测量了大脑的激活，同时我们向参与者展示了场景和人物的图像，并要求他们回忆特定的事件（例如刮胡子，去海滩）以及回忆著名的或个人熟悉的地方和人物。我们的发现揭示了两个关键的见解。首先，我们发现了一个明显的梯度表示从更多的感知相关的更多的记忆相关的从后到前MPC。第二，我们发现MPC中的不同细分在回忆人物或地点时是活跃的。总的来说，这些结果为理解MPC的功能作用及其在认知的不同方面的意义提供了一个新的框架。 2)阐明场景记忆的内容 当我们回忆起以前经历过的事情时，我们到底记得什么？我们的记忆是对那件事的精确、高清晰度的记录，还是那件事的低清晰度的要点，或者甚至只是对我们所看到的东西的口头描述？回答这个问题是能够梳理记忆机制的一个重要组成部分：什么信息被编码和保存，记忆如何随着时间的推移而衰减，以及从这些记忆中提取什么信息。在这项研究中，我们调查的内容记忆的真实的世界的场景使用绘画任务。参与者研究了30个场景，10分钟后，根据记忆尽可能详细地画出尽可能多的图像。数千名在线观察者对由此产生的基于记忆的绘画进行了评分，揭示了许多对象，很少的记忆入侵和精确的空间信息。我们的研究结果表明，在自由回忆过程中，不仅可以量化记忆的内容，而且这些记忆包含了我们视觉体验的详细表征。 阐明大脑如何使我们能够识别物体，场景，面孔和身体，为我们对周围世界的内部表征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精神健康和神经系统疾病的潜在缺陷至关重要。