Attention and Perceptual Learning

描述（由申请人提供）：注意和知觉学习（PL）是已知的两种改善视觉感知的机制，尽管在大多数情况下，它们被分开研究。我建议彻底调查操纵隐蔽注意对视觉感知的影响。视觉感知涉及相对持久（数周或数月）对生物体感知系统的改变。这些变化提高了对环境中事件的反应能力，被认为是成人大脑神经可塑性的表现。PL在心理物理上已经被证明是针对各种感觉模式的许多刺激，并且通常对刺激和任务具有高度特异性。例如，如果观察者（在最初的训练阶段）学会了如何在视野中的特定位置执行任务，他们后来（在测试阶段）在未经训练的位置没有表现出任何好处。注意的运作时间比视觉感知短得多，是选择性地、动态地改善感知表现的最重要的机制。隐蔽注意——在没有眼球运动的情况下，对给定位置的信息进行选择性处理——提高了早期视觉在许多检测、辨别和定位任务中的感知表现。我感兴趣的是外源性（非自愿）和内源性（自愿）隐蔽注意如何影响学习的标志性特异性，以及注意是否可以与学习相互作用，以克服这种限制，提高学习带来的表现。我将使用视觉尺寸，其中PL特异性和注意力调制已被显示；例如，位置、方向和空间频率。研究与注意对视觉视觉的影响相关的心理生理变化将有助于加深对视觉系统可塑性的理解。不同形式的注意力是否以及如何增强成人大脑皮层的可塑性，这个问题在理论上很重要，并具有实际意义。在我们的职业和个人生活中，PL可能是我们在视觉上做得很好的基础，因此具有巨大的基本兴趣和实际重要性。这个问题对于理解和评估视觉系统受损后的康复潜力也是至关重要的。在目前的资助期间，我们对注意力对早期视力的影响进行了自己的研究，这使我们处于一个独特的位置来进行拟议的研究。试点研究表明，注意力在视觉搜索中起着关键和意想不到的作用。我将描述每种类型的注意力的影响，内源性和外源性的，目的如下：(1)视觉搜索中的视觉搜索；(2)考虑视网膜距离、皮质距离和注意窗口大小的基本维度（如对比灵敏度、方向和空间分辨率）相对于定位特异性的PL；(3)特征（如对比敏感度、取向）学习和迁移特异性方面的PL；(4)无觉知的PL。该研究将利用不同的心理物理程序来帮助我们理解大脑可塑性如何改变视觉，以及视觉处理如何与认知，特别是注意力的其他大脑系统相互作用。这些发现将具有理论相关性，并将有助于我们理解和评估视觉系统损伤后康复的潜力。

DESCRIPTION (provided by applicant): Attention and perceptual learning (PL) are two mechanisms known to improve visual perception, though, for the most part, they have been studied separately. I propose to thoroughly investigate the effects of manipulating covert attention on PL. PL involves relatively long-lasting (weeks or months) changes to an organism's perceptual system. Such changes improve the ability to respond to events in the environment and are considered a manifestation of neural plasticity in the adult brain. PL has been demonstrated psychophysically for many stimuli in various sensory modalities, and is often highly specific to stimulus and task. For instance, if observers learn (in the initial training phase) how to perform a task at a particular location in the visual field, they later (in the testing phase) show no benefit at untrained locations. Attention operates on a much shorter timescale than PL and is the most important mechanism that selectively and dynamically improves perceptual performance. Covert attention - the selective processing of information at a given location without eye movements to that location - improves perceptual performance on many detection, discrimination and localization tasks in early vision. I am interested in how exogenous (involuntary) and endogenous (voluntary) covert attention affect the hallmark specificity of PL, and whether attention can interact with learning to overcome this limitation to the improvement in performance PL engenders. I will use visual dimensions for which both PL specificity and modulation by attention have been shown; e.g., location, orientation and spatial frequency. Investigating the psychophysical changes associated with the effects of attention on PL will lead to increased understanding of plasticity in the visual system. The question of whether and how different forms of attention enhance plasticity in the adult cortex is important theoretically and has practical consequences. PL probably underlies most of what we do well visually in our professional and personal lives and is thus of enormous basic interest and practical importance. This question is also crucial for understanding and evaluating the potential of rehabilitation following damage to the visual system. Our own studies on the effects of attention on early vision conducted during the period of the current grant place us in a unique position to conduct the proposed research. Pilot studies indicate that attention plays a pivotal and unanticipated role in PL. I will characterize the effects of each type of attention, endogenous and exogenous, for the following aims: (1) PL in visual search across the visual field; (2) PL of basic dimensions (e.g., contrast sensitivity, orientation and spatial resolution) with regard to location specificity, taking into account retinal distance, cortical distance and the size of the attentional window; (3) PL with regard to feature (e.g., contrast sensitivity, orientation) learning and transfer specificity; (4) PL in the absence of awareness. The proposed research will utilize different psychophysical procedures to contribute to our understanding of how brain plasticity alters vision as indicated by PL, and how visual processing interacts with other brain systems underlying cognition, in particular, attention. The findings will have theoretical relevance and will contribute to our understanding and evaluation of potential of rehabilitation following damage to the visual system. PUBLIC HEALTH RELEVANCE: I propose to thoroughly investigate the effects of manipulating covert attention on PL. PL is the foundation of our visual competence, so the question of whether and how different forms of attention may enhance plasticity in the adult cortex in the general population is important theoretically and has practical consequences. The experimental protocols that I will develop for studying how attention affects perceptual learning in healthy human observers will be readily applicable to patient populations. A better understanding of visual attention and perceptual learning with healthy observers will lead to a better understanding of factors limiting peripheral vision, which are critical when central vision is compromised due to macular degeneration and related visual deficits. Basic knowledge of visual attention has implications for our understanding of several neuropsychological disorders and for informing the development of their diagnostic testing, including unilateral neglect, schizophrenia and ADHD. Basic knowledge of how attention affects perceptual learning has implications for rehabilitation of patients with amblyopia, macular degeneration, and cortical blindness as well as for the evaluation of the potential of visual rehabilitation after trauma and tumors or infarcts ('stroke').