Neural Mechanisms of Visual Crowding

项目摘要 视知觉是一个主动的信息选择过程。这一选择的两个关键组成部分 过程是空间注意和扫视眼动的机制。注意力让我们可以部署 有限的神经资源，用于优先处理显着刺激;扫视使我们能够带来刺激， 注意注视中心进行详细检查。注意力和眼跳的动态相互作用是 在周边视觉中尤其突出，在周边视觉中， 被认为是视觉拥挤的潜在机制之一。视觉拥挤是指无法识别 是周围视觉中物体识别的基本瓶颈。显得尤为 在患有中心视力丧失如黄斑变性（MD）的患者的情况下是有害的，因为这些 个体依赖于外周视网膜位点（PRL）进行物体识别任务。人群密集区， 干扰物影响目标识别的视觉空间沿径向轴沿着显著延长 与正常视力下的中央凹对齐。MD患者的拥挤区经历了系统性重组， 沿所述径向PRL轴线沿着的细长部件。尽管经过几十年的研究， 拥挤和拥挤区的细长形状仍然未知。在本提案中，我们将 在六个神经亚群--两个细胞类别（抑制细胞）--的活性的背景下， 和兴奋性神经元）在三个层（表面，输入，深）-这是基本组成部分的 感觉皮层回路我们的广泛假设是，亚群特定的活动动力学形成了 背景相互作用的基础拥挤和拥挤的形成和重组 区界限我们建议回答关于这个假设的几个关键问题。什么是层流 拥挤区域的语境调节机制（目标1）？宇宙的时空动力学 层皮质回路中的扫视活动（目标2）？拥挤区的神经机制是什么 在中央视觉区（目标3）后进行重组？我们将使用高密度层流 清醒的非人类灵长类动物视觉V4区的神经记录。V4，物体识别中的关键节点 也接收强烈的注意力相关信号和视觉信号的通路非常适合这些 调查事务所这些研究的结果将揭示拥挤的神经机制， 广泛的框架，视觉形式处理的外围，并告知可能的未来干预研究， 中央视力丧失。

Project Summary Visual perception is an active process of information selection. Two critical components of this selection process are the mechanisms of spatial attention and saccadic eye-movements. Attention allows us to deploy limited neural resources for privileged processing of salient stimuli; saccades allow us to bring stimuli of interest to the center of gaze for detailed inspection. The dynamic interplay of attention and saccades is particularly prominent in peripheral vision where inappropriate integration of contextual information has been proposed as one of the underlying mechanisms of visual crowding. Visual crowding is the inability to identify stimuli amidst clutter and is a fundamental bottleneck to object recognition in peripheral vision. It is particularly detrimental in the case of patients with central vision loss such as macular degeneration (MD), since these individuals rely on a peripheral retinal locus (PRL) for object recognition tasks. Crowding zones, the area in visual space over which distractors affect target identification, are markedly elongated along the radial axis aligned with the fovea in normal vision. Crowding zones undergo systematic reorganization in MD patients with an elongated component along the radial PRL axis. Despite decades of research, the neural underpinnings of crowding and that of the elongated shape of crowding zones remain unknown. In this proposal we will bridge these knowledge gaps in the context of the activity of six neural sub-populations – two cell classes (inhibitory and excitatory neurons) in three layers (superficial, input, deep) – that are fundamental components of the sensory laminar cortical circuit. Our broad hypothesis is that sub-population specific activity dynamics form the substrate for contextual interactions underlying crowding and for the formation and re-organization of crowding zones. We propose to answer several key questions regarding this hypothesis. What are the laminar mechanisms of contextual modulation in crowding zones (Aim 1)? What the spatio-temporal dynamics of peri- saccadic activity in the laminar cortical circuit (Aim 2)? What are the neural mechanisms of crowding zone reorganization following central vision zone (Aim 3)? We will achieve these aims using high-density laminar neural recordings in visual area V4 of awake non-human primates. V4, a critical node in the object recognition pathway, that also receives strong attention related and oculomotor signals, is ideally suited for these investigations. The results of these investigations will uncover the neural mechanisms of crowding, provide a broad framework for visual form processing in the periphery and inform possible future intervention studies in central vision loss.