Normalization Model of Attention: Theory, Psychophysics, and Neuroimaging

描述（由申请人提供）：自实验心理学诞生以来，注意力在感知研究中发挥了核心作用。在过去的20年里，视觉注意的神经生理学基础已经成为一个活跃的研究领域，视觉心理物理学领域已经开发出严格的方法来测量和表征注意力对视觉表现的影响，产生了爆炸性的发现。这些实验记录了令人困惑的各种经验现象，其中一些似乎是相互矛盾的。一个例子涉及注意力和视觉刺激对比度之间的相互作用。一些实验的结果表明，注意力通过应用固定的反应增益因子成倍地增加神经元的反应。其他结果表明对比度增益的变化。还有其他的结果表明，注意力可能有一个固定的加性效应，这可以近似为反应增益和对比度增益变化的组合。这些表面上相互矛盾的实证研究结果已经被理论观点所取代，这些理论观点被用来代表注意力的替代模型。我们建议开发和测试的计算理论，称为注意力的正常化模型，并统一/调和各种替代的，看似矛盾的，经验的发现和理论模型的注意力对视觉皮层神经元活动的影响。我们的目标是：（1）表明所提出的模型可以表现出响应增益变化、对比度增益变化以及响应和对比度增益变化的类似加法的组合，这取决于刺激条件和注意力场的扩散;（二）为了检验这一假设，即注意力对行为表现和知觉外观的影响系统地从反应增益的变化转移到对比增益，通过操纵刺激大小和注意场的空间范围;（3）检验模型预测的注意调节视皮层活动的假设，并将皮层活动的注意调节（用功能性磁共振成像测量）与行为表现的注意调节（用心理学测量）联系起来。拟议的研究将利用从各种技术（计算理论，以前的电生理学实验，以及新的心理物理学和功能成像实验）获得的会聚信息，以帮助我们理解大脑如何处理视觉信息，神经活动如何与视觉注意力和感知相关，以及视觉处理如何与其他认知系统相互作用，特别是注意力。 公共卫生相关性：我们为研究健康人类受试者的视觉和注意力而开发的实验方案和理论原则将很容易适用于患者群体。更好地理解视觉注意力将导致更好地理解限制周边视觉的因素，这在黄斑变性和相关视觉缺陷导致中央视觉受损时至关重要。视觉注意力的基本知识对我们理解几种神经心理疾病，包括单侧忽视，精神分裂症和ADHD，以及为这些疾病的诊断测试的发展提供信息具有重要意义。

DESCRIPTION (provided by applicant): Attention has played a central role in perception research since the dawn of experimental psychology. Over the past 20 years, the neurophysiological basis of visual attention has become an active area of research, and the field of visual psychophysics has developed rigorous methods for measuring and characterizing the effects of attention on visual performance, yielding an explosion of findings. These experiments have documented a bewildering variety of empirical phenomena, some of which appear to be mutually contradictory. One example concerns the interaction between attention and visual stimulus contrast. The results of some experiments suggest that attention increases neuronal responses multiplicatively by applying a fixed response gain factor. Other results suggest a change in contrast gain. Still other results suggest that attention may have a fixed additive effect, which can be approximated as a combination of both response gain and contrast gain changes. These ostensibly contradictory empirical findings have been paralleled by theoretical ideas that have been taken to represent alternative models of attention. We propose to develop and test a computational theory, called the normalization model of attention, and to unify/reconcile various alternative, and seemingly conflicting, empirical findings and theoretical models of the effects of attention on neuronal activity in visual cortex. We aim: (1) to show that the proposed model can exhibit response gain changes, contrast gain changes, and additive-like combinations of response and contrast gain changes, depending on the stimulus conditions and the spread of the attention field; (2) to test the hypothesis that the effect of attention on behavioral performance and perceptual appearance systematically shifts from a change in response gain to contrast gain by manipulating the stimulus size and the spatial extent of the attention field; and (3) to test the hypothesis that attention modulates activity in visual cortex as predicted by the model, and to link attentional modulation of cortical activity (as measured with functional magnetic resonance imaging) with attentional modulation of behavioral performance (as measured psychophysically). The proposed research will utilize convergent information gained from various techniques (computational theory, previous electrophysiology experiments, and novel psychophysics and functional imaging experiments) to contribute to our understanding of how the brain processes visual information, how neural activity is related to visual attention and perception, and how visual processing interacts with other brain systems underlying cognition, in particular, attention. PUBLIC HEALTH RELEVANCE: The experimental protocols and theoretical principles that we develop for studying vision and attention in healthy human subjects will be readily applicable to patient populations. A better understanding of visual attention 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, including unilateral neglect, schizophrenia and ADHD, and for informing the development of diagnostic tests of these disorders.