Neural Mechanisms of Feature Integration

描述（由申请人提供）：驱动关于视觉的现代思维的中心观察是视觉系统将刺激分解成其组成特征，由具有不同特征选择性的神经元表示。这些特征选择性神经元携带的信号如何整合到连贯的对象表征中是未知的，并且是神经生物学中未解决的核心问题之一。深入了解解决这个问题的机制，可以通过仔细分析的时间特性的知觉整合在心理物理和神经元水平。我们将遵循这一策略，专注于一个简单而定义明确的特征整合案例：将视觉中两个最基本且研究得最好的特征：颜色和方向结合起来。当前提案的中心目标是了解视觉系统如何结合这些功能。这一目标将通过以下具体目标实现。目标1。在人类的感知水平和BOLD中，以及在猴子的神经元水平上，比较视觉系统对这两个特征的颜色、方向和合取的时间分辨率。目标二。表征调谐颜色和方向的时间动态，它们对亮度对比度的依赖，并量化自然视觉刺激下这些属性的任何变化。目标3。测试空间注意力是否在颜色和方向的整合中发挥作用。相关性：我们目前缺乏对特征整合机制的了解，这表明我们对物体感知受损的疾病病理学的理解存在显着差距，例如同时失认症、面容失认症、整合性视觉失认症、巴林特综合症以及与忽视相关的以物体为中心的损伤。填补这一空白将提供理解，这将有助于解释和治疗这些和相关的疾病。拟议的实验将通过以下方式缩小这一差距：（1）表征介导特征整合的神经机制的时间分辨率;（2）开发和测试介导简单且定义明确的特征整合形式的神经计算的数学严格模型;（3）确定注意力是否在特征连接的形成中发挥作用。

DESCRIPTION (provided by applicant): A central observation that has driven modern thinking about vision is that the visual system decomposes stimuli into their constituent features, represented by neurons with different feature selectivities. How the signals carried by these feature selective neurons are integrated into coherent object representations is unknown and stands as one of the central unsolved questions in neurobiology. Insight into the mechanisms that solve this problem can be gained by carefully analyzing the temporal properties of perceptual integration at the psychophysical and neuronal levels. We will pursue this strategy, focusing on a simple and well-defined case of feature integration: the conjoining of two of the most basic and well studied features in vision: color and orientation. The central objective of the current proposal is to understand how the visual system conjoins these features. This objective will be met in the following specific aims. Aim 1. Compare the temporal resolution of the visual system for color, orientation and conjunctions of these two features, at the perceptual level and in BOLD in humans, and at the neuronal level in monkeys. Aim 2. Characterize the temporal dynamics of tuning for color and orientation, their dependence on luminance contrast, and quantify any changes in these properties under naturalistic visual stimulation. Aim 3. Test whether spatial attention plays a role in the integration of color and orientation. Relevance: Our current lack of knowledge about the mechanisms of feature integration represents a significant gap in our understanding of the pathology of disorders in which the perception of objects is impaired, such as simultagnosia, prosopagnosia, integrative visual agnosia, Balint's syndrome, and object- centered impairments associated with neglect. Filling this gap will provide understanding that will help in the interpretation and treatment of these and related disorders. The proposed experiments will close this gap by (1) characterizing the temporal resolution of the neural mechanisms that mediate feature integration, (2) developing and testing mathematically rigorous models of the neural computations that mediate a simple and well defined form of feature integration, and (3) determining whether or not attention plays a role in the formation of feature conjunctions.