Construction of invariant shape selectivity in the ventral visual stream

描述（由申请人提供）：感知神经科学的一个基本目标是了解我们感知、识别和记忆视觉对象的非凡能力的神经元表征。在人类和非人类灵长类动物中，这些表征是通过处理沿着腹侧视觉流产生的，并通过其最高级别-猴子下颞叶皮层（IT）的神经元活动模式来传达。腹侧流解决的关键计算问题是，它产生视觉图像的IT神经元表示，该视觉图像传达对象身份和类别的选择性，对对象位置、大小、姿势、照明和杂乱的变化具有耐受性（“不变性”）。事实上，虽然腹侧流的形状选择性特性已经得到了很多研究，我们知道很少的机制，构建的耐受性。这个建议的目标是一个机械的理解腹侧视觉流如何构建宽容（“不变”）的视觉形状的选择性，我们的物体识别能力的基础。在目标1中，我们问：自然获得的时间连续的经验“指导”形成的腹侧流的宽容？我们最近发现，IT神经元形状选择性的耐受性可以通过改变无监督视觉对象体验的时间连续性来强烈而快速地塑造。在这个目标中，我们将使用一系列密切相关的视觉经验操作系统地测试和表征这种可塑性的位置，大小和姿态公差学习的作用。这将阐明它在指导成人视觉对象表征中的作用，并为长期研究这些强大的表征在早期发展过程中是如何组装的奠定基础。在目标2中，我们将采取比较的方法来询问对象信息如何在两个腹侧流区域（V4 vs. IT）之间转换。使用相同的猴子，相同的任务，和相同的视觉刺激，我们将使用神经元群体的方法来问：如何从V4表示的IT表示的宽容改变？IT表示中是否保留V4形状选择性？从V4到IT，视觉表示的稀疏性是否发生了变化？容差形状选择性如何在真实的时间内演变？总之，这些实验将告知一个中心问题：“如何在IT中的宽容对象的选择性建立从早期的视觉表示？”，其结果将为腹侧视觉流的计算模型提供强有力的约束，并指导我们更普遍地理解皮层信息转换。 公共卫生相关性：视觉物体识别对我们的健康至关重要，我们的大脑非常擅长解决这个问题，即使同一个物体在我们的眼睛里看起来非常不同。这些实验的首要目标是从机制上理解视觉系统如何构建解决这个问题的神经元活动模式。这将导致对大脑过程的理解，使我们能够看到和评估视觉世界（例如识别和记住物体）。

DESCRIPTION (provided by applicant): A fundamental goal of perceptual neuroscience is to understand the neuronal representations that underlie our remarkable ability to perceive, recognize, and remember visual objects. In humans and non-human primates, these representations are produced by processing along the ventral visual stream, and conveyed by patterns of neuronal activity in its highest level -- the monkey inferior temporal cortex (IT). The key computational problem the ventral stream solves is that it produces an IT neuronal representation of visual images that conveys selectivity for object identity and category, with tolerance ("invariance") to changes in object position, size, pose, illumination and clutter. Indeed, although the shape selectivity properties of the ventral stream have received much study, we know very little about the mechanisms that construct that tolerance. The goal of this proposal is a mechanistic understanding of how the ventral visual stream constructs the tolerant ("invariant") visual shape selectivity that underlies our object recognition abilities. In Aim 1 we ask: does naturally-acquired temporally contiguous experience "instruct" the formation of tolerance in the ventral stream? We have recently discovered that the tolerance of IT neuronal shape selectivity can be strongly and rapidly sculpted by altered temporal contiguity of unsupervised visual object experience. In this aim, we will use a series of closely-related visual experience manipulations to systematically test and characterize the role of this plasticity in position, size, and pose tolerance learning. This will illuminate its role in instructing adult visual object representation, and set the stage for longer-term studies of how these powerful representations are assembled during early development. In Aim 2 we will take a comparative approach to ask how object information is transformed across two ventral stream areas (V4 vs. IT). Using the same monkeys, same task, and same visual stimuli, we will use neuronal population methods to ask: How is the tolerance of the IT representation changed from the V4 representation? Is V4 shape selectivity preserved in the IT representation? Does the sparseness of visual representation change from V4 to IT? How does tolerant shape selectivity evolve in real time? Together, these experiments will inform a central question: "How is the tolerant object selectivity in IT built from earlier visual representation?", and the results will provide strong constraints on computational models of the ventral visual stream and guide our understanding of cortical information transformation more generally. PUBLIC HEALTH RELEVANCE: Visual object recognition is fundamental to our well-being and our brain is remarkably good at solving this problem even though the same object can appear very differently to our eyes. The overarching goal of these experiments is a mechanistic understanding of how the visual system constructs the patterns of neuronal activity that solve this problem. This will lead to an understanding of the brain processes that allow us to see and evaluate the visual world (e.g. recognize and remember objects).