Neural processing in the ventral visual pathway during object search

项目总结 这项建议的目标是准确描述视觉区域中的多个角色 当我们在寻找特定的视觉对象时，大脑就会发挥作用。定位特定对象需要我们1) 激活我们寻找的目标的记忆的神经表征，2)发展一个神经表征 我们在搜索时遇到的每一项，以及3)比较这两个表示以确定 当前查看的对象与我们寻找的对象匹配。我们知道记住一件事的过程 物体激活了大脑中经典定义的“视觉”区域中的神经元，这表明这些视觉区域 可以起到在搜索对象时静态处理视觉场景之外的作用。这个概念是 有其他证据支持，包括我们自己的初步数据。在具体目标1中，我们建议 通过测量当前查看的可视表示在多大程度上描述这一角色 刺激还取决于在不同视觉处理水平(即，区域V4)上寻找的目标的身份 和IT)。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它的探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 当前处于查看范围内的场景。在具体目标2中，我们的动机是现实世界中的对象搜索 涉及在位置、大小、背景和姿势的变化中寻找对象，我们建议 描述视觉系统在通过这些身份的子集搜索目标时的角色- 保留对象变换。最后，在具体目标3中，我们建议表征 视觉神经元当视觉刺激被保存在记忆中但物理上没有视觉刺激时 (“持续活动”)以更好地理解被记忆和寻找的目标在 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.