Neural processing in the ventral visual pathway during object search

描述(由申请人提供)：本方案的目标是准确地描述我们在寻找特定视觉对象时大脑中视觉区域所扮演的多重角色。定位一个特定的物体需要我们1)激活我们寻找的目标的记忆的神经表征，2)开发我们在搜索时遇到的每一项的神经表征，3)比较这两个表征以确定当前在视野中的物体是否与我们寻找的物体匹配。我们知道，记忆物体的过程会激活大脑中经典定义的“视觉”区域中的神经元，这表明这些视觉区域可能起到的作用不仅仅是在搜索物体时静态地处理视觉场景。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观察的刺激的视觉表征在多大程度上也依赖于在不同视觉加工水平(即V4区和IT区)寻找的目标的身份来表征这一角色。一旦找到这样的依赖关系，我们将寻求确定它们完成了什么。例如，视觉系统可能会调整其检测器以提高目标的辨别能力。类似地，这些视觉神经元的反应可能代表了目标和当前视野中的场景之间的比较结果。在具体的目标2中，我们的动机是这样的概念，即现实世界的对象搜索涉及在位置、大小、背景和姿势的变化中寻找对象，并且我们建议表征视觉系统在通过这些保持身份的对象变换的子集搜索目标时的角色。最后，在具体目标3中，我们建议表征当视觉刺激被保存在记忆中但物理上没有视觉刺激时的视觉神经元的活动(“持续活动”)，以更好地理解视觉系统中被记忆和寻找的目标的神经特征。 与公共健康相关：要了解视觉信息是如何在大脑中处理的，最基本的是了解外部世界是如何由视觉皮质中的神经信号表示的，以及记忆和目标是如何影响这种表示并与其相互作用的。这一建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。了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，也是有意义地修复这些大脑过程的破坏或创造可能代表这种破坏的假体所必需的。

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.