Normalization Model of Attention: Theory, Psychophysics, and Neuroimaging

项目摘要 自实验心理学诞生以来，注意力在感知研究中一直扮演着核心角色。来 近20年来，视觉注意的神经生理学基础已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 注意力集中在视觉表现上，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。一个示例 关注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，其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已经被理论观点所证实， 代表了注意力的替代模型。我们建议开发和测试计算理论， 所谓的注意力正常化模型，并统一/调和各种替代方案，似乎 注意力对视觉神经元活动影响的实验研究结果和理论模型相互矛盾， 皮层我们的目标是：（1）表明所提出的模型可以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变化的类似加法的组合，这取决于刺激 条件和注意场的扩散;（2）检验注意对 行为表现和感知外观系统地从反应增益的变化转变为 通过操纵刺激大小和注意场的空间范围来获得对比度增益;以及（3）测试 假设注意力调节视觉皮层的活动，正如模型所预测的那样，并将注意力与视觉皮层的活动联系起来。 注意力对皮质活动的调节（用功能性磁共振成像测量） 行为表现的调节（以精神病学的方式测量）。该研究将利用 从各种技术（计算理论，以前的电生理学）获得的会聚信息 实验，以及新的心理物理学和功能成像实验），以促进我们的理解 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，特别是注意力，相互作用。

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.