Initial stages of visual information processing

视觉信息处理的初始阶段

• 批准号: RGPIN-2014-03845
• 负责人: DiLollo, Vincent
• 金额: $ 4.3万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610681
• 关键词: Initial; stages; visual; information; processing

I plan to work in three distinct but related areas: ITERATIVE-REENTRY MODEL. Advances in neuroscience have called attention to reentrant signalling as the main form of communication between brain regions connected by two-way pathways. Yet, theories of perception continue to be couched in feed-forward sequences. We have developed an alternative account in which perceptions are held to emerge from iterative exchanges between brain regions. That account emerged from the discovery of Object-Substitution Masking (OSM) in which an initial combined display of target and mask continues with the mask alone. The target is identified easily when all display elements terminate together. When the mask alone remains on view, masking occurs, with its strength increasing with the duration of the mask. OSM implicates reentrant processing because it cannot be explained on the basis of feed-forward processes alone. The main objective of the research programme is to explore systematically the perceptual domains in which iterative reentrant processes mediate visual perception, and how that mediation is modulated by the distribution of attention in space and time. These domains include the perception of form based on stimuli that are defined by luminance contours, by relative motion, by segregated texture, and by binocular disparity. EFFICIENCY OF VISUAL SEARCH DURING THE AB. Is the efficiency of visual search in “pop-out” displays, as indexed by the slope of the search function (reaction time over set size), modulated by attention? Earlier work sought to answer this question by presenting the search array while attention was depleted during the period of the AB. For various methodological reasons, that work failed to produce an unequivocal answer. For example, in one case, the search array that acted as the second target (T2) in the AB sequence remained on the screen until response, thus allowing the array to be searched with full attention after T1 had been processed. In another case, search efficiency could not be assessed because only a single set size was used. In a pilot study that avoided the flaws in the earlier work, I found that the efficiency of pop-out search, as indexed by the search slope, is impaired while attention is depleted during the AB. I will examine this finding with different types of search (feature, compound, conjunction search), and will pursue its implication that the establishment of a feature gradient (e.g., texture segmentation) requires attention. TEMPORAL INTEGRATION IN VISION. Quite some time ago, my then graduate student John Hogben and I devised a method of studying temporal integration in vision. Two halves of a dot-matrix pattern are displayed successively, separated by a blank inter-stimulus interval (ISI). Perceptual integration of the two halves deteriorates, and eventually breaks down, as the ISI is increased to 100 ms. In a pilot study, I varied the duration of the two halves of the pattern from 20 to 100 ms, and used a staircase threshold-tracking procedure (PEST) that adjusted the ISI dynamically so as to converge on a critical ISI that yielded an accuracy of 80%. I found that, at exposure durations beyond about 60 ms, a NEGATIVE ISI of up to 100 ms was required to achieve an accuracy of 80%. Namely, a pattern that was easily perceived when displayed briefly as a whole, was destroyed when it was preceded and followed by parts of itself. I plan to pursue this fascinating and counterintuitive finding. The first two projects will also involve the recording of event-related potentials to study the brain’s electrical activity triggered by various stimulus sequences. The ultimate objective is to encompass the results of all three projects within a comprehensive theory based on iterative reentrant processing.

我计划在三个不同但相关的领域工作： 迭代重入模型。神经科学的进步已经引起了人们对折返信号的关注，折返信号是通过双向通路连接的大脑区域之间的主要通信形式。然而，感知理论仍然以前馈序列为基础。我们提出了另一种解释，认为感知是从大脑区域之间的反复交流中产生的。这种解释来自于对象替换掩码（OSM）的发现，在OSM中，目标和掩码的初始组合显示仅继续使用掩码。当所有显示元素一起终止时，目标很容易识别。当遮罩单独保留在视图中时，遮罩发生，其强度随着遮罩的持续时间而增加。OSM涉及可重入处理，因为它不能单独的前馈过程的基础上解释。该研究计划的主要目标是系统地探索感知领域，其中迭代重入过程介导的视觉感知，以及如何通过注意力在空间和时间上的分布来调节这种介导。这些领域包括基于由亮度轮廓、相对运动、分离纹理和双眼视差定义的刺激的形式感知。 AB期间视觉刺激的效率。在“弹出”显示器中视觉搜索的效率，如搜索函数的斜率（反应时间超过设置大小）所指示的，是由注意力调节的吗？早期的工作试图回答这个问题，提出了搜索阵列，而注意力耗尽期间的AB。由于各种方法上的原因，这项工作未能得出明确的答案。例如，在一种情况下，在AB序列中充当第二目标（T2）的搜索阵列保持在屏幕上直到响应，从而允许在处理T1之后以完全注意力搜索阵列。在另一种情况下，无法评估检索效率，因为只使用了单一的集合大小。在一项避免了早期研究中缺陷的试点研究中，我发现，当注意力在AB期间耗尽时，弹出搜索的效率（由搜索斜率索引）会受到损害。我将用不同类型的搜索（特征、复合、合取搜索）来检验这一发现，并将探讨其含义，即建立特征梯度（例如，纹理分割）需要注意。 视觉中的时间整合。很久以前，我和当时的研究生约翰·霍格本设计了一种研究视觉时间整合的方法。点阵图案的两个半部被连续显示，由空白刺激间间隔（ISI）分隔。感知集成的两个半恶化，并最终打破，ISI增加到100毫秒。在试点研究中，我改变了持续时间的两个半的模式从20到100毫秒，并使用了阶梯阈值跟踪程序（PEST），调整ISI动态，以便收敛到一个关键的ISI，产生了80%的准确度。我发现，在曝光持续时间超过约60 ms时，需要高达100 ms的负ISI才能达到80%的准确度。也就是说，一个模式，很容易被感知时，短暂地显示为一个整体，被破坏时，它的前面和后面的部分本身。我打算继续研究这个有趣而又违反直觉的发现。 前两个项目还将涉及事件相关电位的记录，以研究由各种刺激序列触发的大脑电活动。最终的目标是包括所有三个项目的结果在一个全面的理论基础上迭代重入处理。