The Neural Mechanisms Underlying the Guidance of Visual Attention

描述(申请人提供)：我们研究视觉注意，因为它在视觉感知中的重要性。行为范式，如改变失明，已经告诉我们，虽然我们认为我们感知到了整个视觉世界，但我们只带走了我们所关注的区域或对象的信息。因为视觉注意力是视觉感知的基础，它是我们与感知世界的大多数互动的基础--包括我们的身体互动和更多的智力互动，如学习和记忆。因此，增加我们对注意力引导机制的理解，对于让我们更深入地洞察大脑如何根据外部和认知输入做出决定，以及从长远来看，洞察视觉感知本身的机制至关重要。在这项研究中，我们检验了这样一种假设，即外侧顶叶内区域(LIP)充当优先图--用于指导注意力分配的视觉世界图。其理论是，注意力被分配到地图上活动最多的位置。我们假设这张地图被用来引导外周(隐蔽)注意力和眼球运动(显性注意力)。在目标1中，我们将通过比较隐蔽注意力分散、聚焦或偏向特定位置的条件下嘴唇和视觉区域V4的活动来检验这一假设。我们预测，V4中的活动将以一种与LIP中活动的空间分布直接相关的方式被调制-LIP中的活动峰值将在V4中产生强烈的注意调节。我们将通过刺激LIP并显示V4活性的可预测调制来进一步测试这一点。在目标2中，我们将测试我们的系统模型所做出的预测，即一旦一个对象被观察，它就会在地图上被抑制，从而使凝视的焦点(即。公开注意)不只是在地图上的两个最高点之间跳跃。我们将通过检查嘴唇对相同刺激的活动来测试这一点，在之前没有或没有观察过的条件下。我们预计，在已经看到刺激措施的情况下，反应将显著降低。然后，我们将通过在任务期间刺激LIP来测试这种活动减少是否对行为重要。我们预计，在没有刺激的试验中，这将导致在刺激位置对视觉刺激进行更多的眼睛运动，而不是对相同的刺激进行更多的眼睛运动。这些实验旨在了解嘴唇在注意力分配中所起的作用，其结果可能被用来微调我们的注意力分配模型。公共卫生相关性这项研究的结果帮助我们理解大脑决定什么值得关注的方式。鉴于视觉注意在日常生活中的重要性，以及在顶叶损伤或注意力缺陷障碍患者中所见的缺陷，对这一机制的更多了解可能有助于开发出应对这些问题的药物或行为方法。

Description (provided by applicant): We study visual attention because of its importance in visual perception. Behavioral paradigms, such as change blindness, have shown us that while we think we perceive the whole visual world, we only take away information about regions or objects that we have attended. Because visual attention is a foundation of visual perception, it underlies most of our interactions with the perceived world - both our physical interactions and more intellectual interactions, such as learning and memory. Thus, increasing our understanding of the mechanisms underlying the guidance of attention is critical in allowing us to gain a deeper insight into how the brain makes decisions based on both external and cognitive inputs and, in the long run, insight into the mechanisms underlying visual perception itself. In this study, we test the hypothesis that the lateral intraparietal area (LIP) acts as a priority map - a map of the visual world that is used to guide the allocation of attention. The theory is that attention is allocated to the location on the map with the greatest activity. We have hypothesized that this map is used to guide both peripheral (covert) attention and eye movements (overt attention). In aim 1, we will test this hypothesis by comparing the activity in LIP and visual area V4 under conditions in which covert attention is spread, focused or biased to a particular location. We predict that activity in V4 will be modulated in a way that is directly related to the spatial distribution of activity in LIP - a peak of activity in LIP will produce strong attentional modulation in V4. We will further test this by stimulating LIP and showing predictable modulation in V4 activity. In aim 2, we will test a prediction made by our model of the system, namely that once an object has been looked at, it is suppressed on the map so that the focus of gaze (ie. overt attention) doesn't just bounce between the two highest points on the map. We will test this by examining the activity in LIP to an identical stimulus under conditions in which it has or has not been looked at previously. We expect that the response will be significantly lower in the case in which the stimulus has already been seen. We will then test whether this reduction in activity is important to the behavior by stimulating LIP during the task. We expect that this will result in more eye movements being made to the visual stimulus at the stimulated location than to the same stimulus in trials in which stimulation does not occur. These experiments are aimed at understanding the role that LIP plays in the allocation of attention and the results may be used to fine-tune our model of how attention is allocated. PUBLIC HEALTH RELEVANCE The results from this study help us understand the way the brain decides what is worth paying attention to. Given the importance of visual attention in everyday life and the deficits seen in patients with parietal lesions or attention deficit disorders, a greater understanding of this mechanism may aid in the development of pharmacological or behavioral methods to combat these problems.