Normalization Model of Attention: Theory, Psychophysics, and Neuroimaging

描述(由申请人提供)：自从实验心理学诞生以来，注意力在知觉研究中一直扮演着中心角色。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表征注意对视觉表现的影响，产生了大量的发现。这些实验记录了各种令人困惑的经验现象，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，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，注意力可能具有固定的加性效应，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经验发现，与被用来代表另一种注意力模式的理论观点相一致。我们建议开发和测试一种称为注意力归一化模型的计算理论，并统一/协调关于注意对视皮层神经元活动的影响的各种不同的、似乎相互冲突的经验发现和理论模型。我们的目标是：(1)证明所提出的模型能够根据刺激条件和注意领域的扩展呈现反应增益变化、对比增益变化以及反应和对比增益变化的类似加法的组合；(2)通过控制刺激大小和注意领域的空间范围来检验注意对行为表现和知觉外观的影响从反应增益变化系统地转变为对比增益变化的假设；以及(3)检验模型预测的注意力调节视皮层活动的假设，并将注意力调节皮层活动(如功能磁共振成像测量)与注意调节行为表现(如心理生理测量)联系起来。这项拟议的研究将利用从各种技术(计算理论、先前的电生理学实验以及新的心理物理学和功能成像实验)获得的融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知觉相关，以及视觉处理如何与其他大脑系统相互作用，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力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。更好地了解视觉注意将有助于更好地了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.