HOW DOES ATTENTION ALTER APPEARANCE? PSYCHOPHYSICS AND NEUROPHYSIOLOGY

描述(申请人提供)：视觉感知并不总是我们环境的真实表现。相反，视觉场景的处理受到注意力选择性分配的影响。有人值守的地点的视力更快、更准确、空间分辨率更高[1-11，回顾见12]。通过以无人值守场所为代价改进有人值守场所的信息处理，注意力使我们能够最有效地利用视觉系统有限的资源。最近的研究表明，注意力不仅能提高表现，还能改变一些基本视觉特征的外观[13-22]。一些作者批评了对这些发现的解释，并提出了基于决策偏差的替代解释，即人们更有可能选择一个参与的刺激，但没有不同的感知[23-26]。尽管这一说法已被对照实验[13，15-21]和经验性回答[14，27，28]反驳，但这一问题仍在激烈辩论中。这种对现象学经验的注意调节的生理学基础尚不清楚。虽然增强的神经元反应解释了注意力表现的提高，但这并不一定意味着外表的改变。相反，刺激特征的出现往往与选择性地调整这些特征的神经元群体的活动有关，而误解与它们选择性的变化有关[49]。因此，外观的改变应该通过参与处理所关注的刺激的神经元群体的选择性的改变来调节。这项拟议的研究将首次测试空间注意对神经元群体对基本视觉特征的选择性的影响，从而将显著有助于理解空间注意的机制。此外，它将为注意力是否真的影响外表这一问题提供一个明确的答案。将采用一种适应范式，在这种范式中，调谐到特定刺激特征的神经元群体可以在心理物理范式中选择性地被瞄准，因此适应和注意的交互作用将揭示这些神经元是否介导了对外表的注意效应。然后，将使用功能磁共振成像(FMRI)范例中的适应来直接测量注意和不注意情况下的群体选择性[29]。速度和空间频率分别被选为背侧流和腹侧流的两个例子，因为注意力调节速度和空间频率的出现[18，20]和空间频率[15，30]，并且因为早期视皮层中存在同时调节速度和空间频率的神经元[31-38]。心理物理和功能磁共振研究的结果将为空间注意力如何改变外表提供汇聚和补充的证据。 公共卫生相关性：拟议的研究将进一步加深我们对视觉注意的生理基础和机制的理解。这些基础研究为开发治疗注意力相关疾病的临床应用奠定了基础，例如单侧忽视或注意力缺陷多动障碍(ADHD)。

DESCRIPTION (provided by applicant): Visual perception is not always a veridical representation of our environment. Instead, processing of the visual scene is influenced by the selective allocation of attention. Vision at an attended location is faster, more accurate, and of higher spatial resolution [1-11, for a review see 12]. By improving information processing at attended locations at the cost of unattended locations, attention allows us to make most efficient use of the visual system's limited resources. Recent studies show that attention not only improves performance but also alters the appearance of several basic visual features [13-22]. Some authors have criticized the interpretation of these findings and suggested alternative explanations based on a decisional bias, i.e., people are more likely to select an attended stimulus but do not perceive it differently [23-26]. Although this account has been counter-argued by control experiments [13, 15-21] and empirical replies [14, 27, 28], the issue is still hotly debated. The physiological basis of such an attentional modulation of phenomenological experience is not yet known. Whereas an enhanced neuronal response explains increased performance with attention, it does not necessarily imply a change of appearance. Instead, the appearance of stimulus features has often been associated with the activity of neuronal populations selectively tuned for these features, and misperceptions have been related to shifts in their selectivity [49]. Therefore, a change of appearance should be mediated by shifts in the selectivity of those neuronal populations involved in processing the attended stimulus. The proposed research will be the first to test effects of spatial attention on neuronal population selectivity for basic visual features and will thereby significantly contribute to understanding the mechanisms of spatial attention. Furthermore, it will provide a definitive answer to the question whether attention truly modulates appearance. An adaptation paradigm will be employed in which neuronal populations tuned to specific stimulus features can be selectively targeted in a psychophysical paradigm, so that an interaction of adaptation and attention will reveal if these neurons mediate the attentional effect on appearance. Then, population selectivity will be directly measured with and without attention using adaptation in a functional magnetic resonance imaging (fMRI) paradigm [29]. Speed and spatial frequency were chosen as two respective examples from the dorsal and ventral streams, because attention modulates the appearance of both speed [18, 20] and spatial frequency [15, 30] and because neurons tuned for both speed and spatial frequency exist in early visual cortex [31-38]. Results from both the psychophysical and the fMRI study will provide converging and complementing evidence for how spatial attention changes appearance. PUBLIC HEALTH RELEVANCE: The proposed research will further our understanding of the physiological basis and mechanisms of visual attention. Such basic research lays the foundation to develop clinical applications to treat attention-related disorders, for example unilateral neglect or Attention-Deficit Hyperactivity Disorder (ADHD).