Normalization Model of Attention: Theory, Psychophysics, and Neuroimaging

项目摘要 自从实验心理学诞生以来，注意就一直在知觉研究中发挥着核心作用。超过了 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，而 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 对视觉表现的关注，产生了爆炸性的发现。这些实验记录了一个 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 关注注意力与视觉刺激对比度之间的相互作用。一些实验的结果 提示注意力通过应用固定的反应增益因子以倍增的方式增加神经元的反应。 其他结果表明，对比度增益发生了变化。还有其他结果表明，注意力可能有一个固定的 相加效应，可以近似为响应增益和对比度增益变化的组合。 这些表面上相互矛盾的经验发现与理论观点相一致，这些理论观点 被用来代表另一种注意力模式。我们建议开发和测试一种计算理论， 被称为注意力的常态化模型，并统一/调和各种替代方案，看似 注意对视觉神经元活动影响的相互矛盾的经验发现和理论模型 大脑皮层。我们的目标是：(1)证明所提出的模型能够表现出响应增益的变化、对比度增益 变化，以及响应和对比度增益的类似加法组合的变化，取决于刺激 条件与注意领域的扩散；(2)检验注意对注意的影响 行为表现和知觉表象从反应增益的变化系统地转变为 通过操纵刺激大小和注意区域的空间范围来获得对比增益；以及(3)测试 模型预测的注意调节视觉皮质活动的假说，并将注意与 注意对皮层活动的调节(用功能磁共振成像测量) 行为表现的调节(根据心理生理的测量)。拟议的研究将利用 从各种技术(计算理论、先前的电生理学)获得的融合信息 实验，以及新颖的心理物理学和功能成像实验)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力和知觉相关， 以及视觉处理如何与认知基础的其他大脑系统相互作用，特别是注意力。

Project Summary 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.