Neural Visual Coding: Image to Object Representation

描述(由申请人提供)：研究是为了促进我们对视觉知觉组织的神经机制及其与选择性注意的关系的理解。长期目标是在神经信号水平上理解感觉表征和认知过程之间的接口。本研究的重点是图形-背景的组织机制，从边界所有权的神经表征中可以明显看出，即将轮廓分配给物体。通常的方法是从清醒的行为猕猴的视皮层进行单细胞记录。已经确定了未来五年的三大目标。第一个目的是定量描述边界所有权选择性V2神经元的空间整合机制。先前的研究表明，这些机制远远超出了神经元的经典感受野。将应用两种具有析因设计的方法。这些方法可以测量超经典区域与经典感受野的非线性相互作用，以及超经典区域之间的相互作用。这两种方法是互补的。一种是对图形进行碎片化处理，另一种是对关键特征进行遮挡。第二个目的是研究图形-背景组织在视觉皮质中的持续性。实验的目的是(1)确定图形-背景线索的类型及其持续时间对后续边界所有权信号的持续性的影响；(2)确定持续性是否依赖于对图形的注意；(3)边界所有权信号是否在眼动和刺激运动中持续存在。第三个目的是研究神经组织机制在基于对象的选择性注意中的作用。在先前结果的基础上，V2神经元将边界所有权编码与意志选择性注意的影响结合在一起，新的实验将测试物体被部分遮挡的视觉条件，以便只有两个不相连的部分保持可见。结果将显示，边界所有权机制是否可以将跨越差距的特征链接起来，以及基于对象的注意力是否可以做到这一点。这项拟议的研究将有助于澄清选择性注意的基础，选择性注意对于理解正常和受损的视力都很重要。尽管这项研究的重点是视觉，但这项研究将有助于识别其他形式的感觉-认知接口。从这个项目中获得的洞察力将有助于理解阅读障碍等认知障碍的基础。与公共健康相关的选择性注意可能是视觉中最重要的功能。我们可以选择处理一行文本中的单词，而忽略所有其他单词，这使我们能够阅读。但有时我们看不到就在我们眼前的事情--许多交通事故的原因。阅读困难症儿童无法察觉其他人容易看到的字母串之间的差异。这项拟议的研究的目标是了解大脑中的一个过程，该过程在对象被识别之前将图像分解为对象，从而提供一种内部表征，供注意力从中进行选择。

DESCRIPTION (provided by applicant): Research is proposed to advance our understanding of the neural mechanisms of visual perceptual organization and their relation to selective attention. The long-term objective is to understand the interface between sensory representations and cognitive processes at the neural signal level. The proposed research focuses on the mechanisms of figure-ground organization as evident from the neural representation of border ownership, i.e., the assignment of contours to objects. The general method is single-cell recording from the visual cortex of awake behaving macaques. Three broad aims have been identified for the next five years. The first aim is to provide quantitative descriptions of the spatial integration mechanisms of border ownership selective V2 neurons. Previous studies have shown that these mechanisms extend far beyond the classical receptive field of the neurons. Two methods with factorial design will be applied. These methods allow to measure nonlinear interactions of the extra-classical regions with the classical receptive field as well as interactions between extra-classical regions. The two methods are complementary. One uses fragmentation of figures, the other uses occlusion of critical features. The second aim is to study persistence of figure-ground organization in the visual cortex. Experiments are proposed to (1) determine the influence of the type of figure-ground cue and its duration on the subsequent persistence of border ownership signals, (2) determine whether the persistence depends on attention being directed to the figure, and (3) whether border ownership signals persist across eye movements and stimulus movements. The third aim is to study the role of the neural organization mechanisms in object-based selective attention. Building on previous results showing that V2 neurons combine border ownership coding with the influence of volitional selective attention, new experiments will test visual conditions in which an object is partially occluded, so that only two unconnected portions of it remain visible. The results will show whether the border ownership mechanisms can link features across the gap, and whether object-based attention can do so. The proposed research will help to clarify the basis of selective attention which is important for understanding both normal and impaired vision. Although the proposal is focused on vision, the research will help to identify the sensory-cognitive interface also in other modalities. The insight gained from this project will contribute to the understanding of the basis of cognitive disorders such as dyslexia. PUBLIC HEALTH RELEVANCE Selective attention is perhaps the most important function in vision. We can choose to process the words in one line of text and ignore all others, which enables us to read. But sometimes we do not see things that are right in front of our eyes-the cause of many traffic accidents. Dyslexic children cannot detect the difference between strings of letters that others can easily see. The goal of the proposed research is to understand a process in the brain that dissects images into objects before objects are recognized, providing an internal representation from which attention can select.