Attention and Perceptual Learning

描述(申请人提供)：注意和知觉学习(PL)是两种已知的提高视觉感知的机制，尽管在大多数情况下，它们已经被分开研究。我建议彻底调查操纵隐性注意对PL的影响。PL涉及有机体知觉系统相对持久的(几周或几个月)变化。这种变化提高了对环境事件的反应能力，被认为是成人大脑神经可塑性的一种表现。PL已经被证明对各种感觉方式中的许多刺激具有心理生理作用，并且通常对刺激和任务具有高度的特异性。例如，如果观察者(在最初的训练阶段)学习如何在视野中的特定位置执行任务，他们随后(在测试阶段)在未训练的位置没有显示出任何好处。注意力的作用时间比PL短得多，是选择性地、动态地提高知觉表现的最重要的机制。隐蔽注意--在没有眼球运动的情况下，对特定位置的信息进行选择性处理--改善了早期视觉中许多检测、辨别和定位任务的知觉表现。我感兴趣的是，外源性(非自愿)和内源性(自愿)的内隐注意如何影响PL的特征专一性，以及注意是否可以与学习相互作用来克服这种限制，从而提高PL的成绩。我将使用视觉维度，这些维度既显示了PL的专一性，也显示了注意力的调节；例如，位置、方向和空间频率。研究与注意对PL的影响相关的心理物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质的可塑性，这一问题在理论上很重要，也有实际意义。PL可能是我们在职业和个人生活中视觉上做得最好的大部分东西的基础，因此具有巨大的基本兴趣和实际重要性。这个问题对于了解和评估视觉系统受损后康复的潜力也是至关重要的。我们自己关于注意力对早期视力影响的研究是在目前的拨款期间进行的，这使我们处于一个独特的位置来进行拟议的研究。初步研究表明，注意力在PL中扮演着一个关键且出人意料的角色。我将描述每一种类型的注意的影响，包括内源性和外源性，以达到以下目的：(1)跨视野视觉搜索的PL；(2)关于位置专一性的基本维度的PL(例如，对比敏感度、方位和空间分辨率)，考虑到视网膜距离、皮质距离和注意窗口的大小；(3)关于特征(例如，对比敏感度、方位)学习和迁移专一性的PL；(4)在没有意识的情况下的PL。这项拟议的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其他认知系统，特别是注意力相互作用。这些发现将具有理论上的相关性，并将有助于我们理解和评估视觉系统损伤后的康复潜力。 公共卫生相关性：我建议彻底调查操纵隐蔽注意力对PL的影响。PL是我们视觉能力的基础，因此，不同形式的注意是否以及如何在普通人群中增强成人皮质的可塑性这一问题在理论上是重要的，并且具有实际意义。我将为研究注意力如何影响健康人类观察者的知觉学习而开发的实验方案将很容易适用于患者群体。与健康的观察者一起更好地理解视觉注意和知觉学习将有助于更好地理解限制周边视力的因素，当中心视力因黄斑变性和相关的视觉缺陷而受到损害时，这些因素是至关重要的。视觉注意的基本知识对我们理解几种神经心理障碍以及为其诊断测试的发展提供信息，包括单边忽视、精神分裂症和ADHD。注意力如何影响知觉学习的基本知识对弱视、黄斑变性和皮质失明患者的康复以及对创伤、肿瘤或脑梗塞(中风)后视觉康复潜力的评估具有重要意义。

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').