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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631394
• 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开展工作：神经科学的进步引起了人们对重入信号的关注，它是通过双向通路连接的大脑区域之间交流的主要形式。然而，知觉理论继续在前馈序列中表达。我们已经发展了另一种说法，认为知觉是由大脑区域之间的反复交换产生的。这种说法来自于Object-Substitution Masking （OSM）的发现，在OSM中，目标和掩码的初始组合显示继续单独显示掩码。当所有显示元素一起终止时，目标很容易识别。当面具单独保持在视野中时，掩蔽发生，其强度随着面具的持续时间而增加。OSM涉及可重入处理，因为它不能仅在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迭代重入过程介导视觉感知的感知领域，以及这种中介如何通过空间和时间上的注意力分布进行调节。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期间视觉搜索的效率。“弹出式”显示的视觉搜索效率是否由搜索函数的斜率（反应时间超过设定的大小）来调节？早期的工作试图通过在AB期间注意力耗尽时呈现搜索阵列来回答这个问题。由于各种方法上的原因，该工作未能产生明确的答案。例如，在一种情况下，作为AB序列中第二个目标（T2）的搜索数组在响应之前一直在屏幕上显示，从而允许在处理T1之后对该数组进行充分的关注搜索。在另一种情况下，无法评估搜索效率，因为只使用了单个集合大小。在一项避免了早期工作中的缺陷的初步研究中，我发现，在AB过程中，随着注意力的消耗，以搜索斜率为索引的弹出式搜索的效率受到损害。我将用不同类型的搜索（特征、复合、连接搜索）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）需要注意力。视觉的时间整合。很久以前，我当时的研究生John Hogben和我设计了一种研究视觉时间整合的方法。点阵图案的两半连续显示，由空白刺激间隔（ISI）分隔。当ISI增加到100 ms时，两半的感知整合会恶化，并最终崩溃。在一项初步研究中，我将模式的两半的持续时间从20毫秒改变为100毫秒，并使用阶梯阈值跟踪程序（PEST）动态调整ISI，以便收敛于产生80%精度的关键ISI。我发现，在曝光时间超过约60毫秒时，需要高达100毫秒的负ISI才能达到80%的精度。也就是说，当一个模式作为一个整体被短暂地展示出来时，它很容易被感知，当它被自己的部分所取代时，它就被摧毁了。我打算继续研究这个有趣又违反直觉的发现。前两个项目还将包括记录事件相关电位，以研究由各种刺激序列引发的大脑电活动。最终目标是在基于迭代可重入处理的综合理论中包含所有三个项目的结果。