Neural processing in the ventral visual pathway during object search

项目摘要 本提案的目的是准确描述视觉区域在视觉系统中的多重作用， 当我们在寻找特定的视觉对象时，大脑会发挥作用。定位一个特定的对象需要我们1） 激活我们所寻找的目标的记忆和神经表征，2）发展一种神经表征， 我们在搜索时遇到的每一个项目，以及3）比较这两个表示以确定 当前视图中的对象与我们查找的对象匹配。我们知道记忆的过程 物体激活了大脑中经典定义的“视觉”区域的神经元，这表明这些视觉区域 可以在搜索对象时扮演超出静态处理视觉场景的角色。这个概念是 其他证据也证实了这一点，包括我们自己的初步数据。在具体目标1中，我们建议 通过测量当前观看的视频的视觉表示在多大程度上 刺激还取决于在视觉处理的不同水平（即区域V4）处所寻找的目标的身份 和IT）。在找到这些依赖关系后，我们将试图确定它们实现了什么。比如说， 视觉系统可以调整其检测器以增加目标的可辨别性。同样， 这些视觉神经元的反应可能代表了目标和目标之间比较的结果。 目前，现场正在观察中。在具体目标2中，我们的动机是现实世界的对象搜索 涉及到在位置、大小、背景和姿势的变化中找到一个物体，我们建议 描述视觉系统在这些身份的子集中搜索目标的作用- 保持对象变换。最后，在具体目标3中，我们建议描述 视觉神经元当视觉刺激被保存在记忆中，但没有视觉刺激存在时 （“持续活动”），以更好地理解记忆和寻找的目标在大脑中的神经信号。 视觉系统

Project summary 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.