Neural processing in the ventral visual pathway during object search

描述（由申请人提供）：本提案的目标是准确描述当我们寻找特定视觉对象时大脑中视觉区域所扮演的多种角色。定位一个特定的物体需要我们：1）激活我们所寻找的目标的记忆神经表征; 2）开发我们搜索时遇到的每个项目的神经表征; 3）比较这两种表征，以确定当前看到的物体是否与我们所寻找的物体相匹配。我们知道，记忆一个物体的过程会激活大脑中经典定义的“视觉”区域的神经元，这表明这些视觉区域在搜索物体时可能发挥着超越静态处理视觉场景的作用。这一观点得到了其他证据的支持，包括我们自己的初步数据。在具体目标1中，我们建议通过测量当前看到的刺激的视觉表示在多大程度上也取决于在不同视觉处理水平（即V4区和IT区）寻求目标的身份来表征这种作用。在找到这些依赖关系后，我们将试图确定它们实现了什么。例如，视觉系统可能会调整其探测器以增加目标的可辨别性。类似地，这些视觉神经元的反应可能代表目标和当前视野中的场景之间的比较结果。在具体目标2中，我们的动机是这样一个概念，即现实世界中的对象搜索涉及到在位置，大小，背景和姿态的变化中找到一个对象，我们建议描述视觉系统在这些身份保持对象变换的子集中搜索目标的作用。最后，在具体目标3中，我们建议描述视觉神经元的活动，当视觉刺激被保存在记忆中，但没有视觉刺激物理存在（“持续活动”），以更好地理解记忆和寻找的目标在视觉系统中的神经签名。 公共卫生相关性：要了解视觉信息是如何在大脑中处理的，最基本的是要了解外部世界是如何由视觉皮层中的神经信号表示的，以及记忆和目标如何影响和相互作用。这个提议试图理解视觉系统在寻找特定视觉对象时转换图像的神经表征的基本原理。理解物体的神经编码对于深入理解人类的视觉感知和记忆至关重要，并且需要有意义地修复这些大脑过程的中断或创建可能代替这种中断的假肢。

DESCRIPTION (provided by applicant): The goal of this proposal is to arrive at an accurate description of the multiple roles that visual areas in the brain play when we are looking for a specific visual object. Locating a specific object requires that we 1) activate a remembered, neural representation of our sought target, 2) develop a neural representation of each item we encounter as we search, and 3) compare these two representations to determine whether the object currently in view matches the object that we seek. We know that the process of remembering an object activates neurons in classically defined 'visual' areas of the brain, suggesting that these visual areas may play a role beyond statically processing the visual scene when searching for an object. This notion is supported by other lines of evidence, including our own preliminary data. In Specific Aim 1, we propose to characterize this role by measuring the degree to which the visual representation of a currently viewed stimulus also depends on the identity of a sought target at different levels of visual processing (i.e. areas V4 and IT). Upon finding such dependencies, we will seek to determine what they accomplish. For example, the visual system might adjust its detectors to increase the discriminability of a target. Similarly, the responses of these visual neurons may represent the outcome of a comparison between the target and the scene currently held in view. In Specific Aim 2, we are motivated by the notion that real-world object search involves finding an object across changes in position, size, background and pose, and we propose to characterize the role of the visual system in searching for a target across a subset of these identity- preserving object transformations. Finally, in Specific Aim 3, we propose to characterize the activity of visual neurons when a visual stimulus is held in memory but no visual stimulus is physically present ("persistent activity") to better understand the neural signature of the remembered and sought target in the visual system. PUBLIC HEALTH RELEVANCE: To understand how visual information is processed in the brain, it is fundamental to understand how the external world is represented by neural signals in visual cortex and how memories and goals influence and interact with that representation. This proposal seeks to understand the fundamental principles by which the visual system transforms the neural representation of images when looking for a specific visual object. Understanding the neural coding of objects is critical to a deep understanding of human visual perception and memory, and is needed to meaningfully repair the disruption of these brain processes or to create prosthetics that may stand in for such disruption.