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，注意力一直在感知研究中发挥着核心作用。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发展出严格的方法来测量和描述注意力对视觉表现的影响，并产生了大量的发现。这些实验记录了令人眼花缭乱的各种经验现象，其中一些似乎是相互矛盾的。一个例子是关于注意和视觉刺激对比之间的相互作用。一些实验结果表明，注意通过应用固定的反应增益因子成倍地增加神经元反应。其他结果表明对比度增益发生了变化。还有一些结果表明，注意力可能具有固定的加性效应，可以近似为响应增益和对比增益变化的组合。这些表面上相互矛盾的经验发现，已经被用来代表其他注意模型的理论观点所平行。我们建议开发和测试一种计算理论，称为注意力的正常化模型，并统一/调和各种替代的，似乎相互矛盾的，关于注意力对视觉皮层神经元活动影响的经验发现和理论模型。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，对比增益变化，以及响应和对比增益变化的加性组合，这取决于刺激条件和注意场的扩展；(2)通过控制刺激大小和注意场的空间范围，验证注意对行为表现和知觉外观的影响从反应增益到对比增益的系统性转变；(3)验证模型所预测的注意调节视觉皮层活动的假设，并将皮层活动的注意调节（通过功能性磁共振成像测量）与行为表现的注意调节（通过心理物理测量）联系起来。该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）中获得的聚合信息来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和感知相关，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。

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.