Roles of Attention in Motion Processing

9631573渡边的视觉感知通常被认为是一种被动和简单的事件。这一观点在一定程度上源于一种普遍的假设，即视觉信息只从视网膜传递到大脑的高级区域，而不是相反的方向。然而，最近的解剖学和生理学发现表明，大脑中有大量的反馈通路，沿着这些通路，信息从这些较高水平的大脑区域返回到低水平区域，包括那些处理视觉信息的区域。目前还不清楚这些反馈投射在大脑的视觉信息处理中起到什么作用。这项研究涉及注意力的作用，注意力是起源于高级大脑区域的最重要的认知功能之一。它将考察受注意力影响最低的视觉处理水平。回答这个问题将使我们更好地理解从认知功能可能起源的高级大脑区域向较低级别视觉处理的反馈投射所起的作用。在一系列实验中，人们将在电脑显示器上观看一个移动的物体，并被指示只注意物体的局部轮廓。在运动物体开始运动一分钟后，将测量每个人对几个方向的运动的敏感度，如向上和向右运动。已知运动处理至少有两个阶段：在第一阶段中，视觉系统不检测整个对象的运动方向。仅检测垂直于运动对象的局部轮廓的许多局部运动分量。这一阶段始于初级视觉皮质，在那里发生了非常低水平的视觉处理。在第二阶段中，对检测到的这些局部运动分量的方向的信号进行积分，从而可以计算出整个物体的真实运动方向。在这些实验中，如果注意影响了运动加工的第一阶段，对最初参与的局部运动的敏感度应该会降低。另一方面，如果注意不影响加工的低水平阶段，对运动方向的敏感性不应该受到注意分配的影响。仅用两个人进行的初步实验结果表明，前者就是这种情况。如果这一结果得到更多人的证实，将表明注意可以影响视觉信息处理的非常原始的阶段，从而得出结论，反馈投射在使视觉感知活跃并受到高级认知功能影响方面发挥着非常重要的作用，而不是完全被动和自动的。这些结果应该对计算机视觉系统的设计有重要的影响，这是一个非常困难的计算机问题。***

9631573 WATANABE Visual perception is often considered a passive and simple event. This view derives partly from the general assumption that visual information goes only from the retina to higher-level areas in the brain, and not in the other direction. However, recent anatomical and physiological findings indicate that there are massive feedback pathways in the brain along which information is carried from these higher-level brain areas back to low-level areas, including those processing visual information. It is not yet well known what role these feedback projections play in visual information processing in the brain. This research is concerned with the role of attention, one of the most important cognitive functions originating in higher brain areas. It will examine what level of visual processing is the lowest that can be influenced by attention. Answering this question will lead to a better understanding of the role of feedback projections from high-level brain areas, where cognitive functions likely originate, to lower level visual processing. In a series of experiments, people will watch a moving object on a computer display and will be instructed to pay attention only to a local contour of the object. One minute after the onset of the moving object, each person's sensitivity to motion in several directions, such as upward and rightward, will be measured. Motion processing is known to have at least two stages: In the first stage, the direction of motion of the whole object is not detected by the visual system. Only the many local motion components perpendicular to the local contours of a moving object are detected. This stage begins in the primary visual cortex in which very low-level visual processing occurs. In the second stage, the signals from detection of the directions of these local motion components are integrated, so that the true direction of motion of the entire object can be calculated. In these experiments, if attention influences the first stage of motion processing, sensitivity to the originally attended local motion should decrease. On the other hand, if attention does not influence such a low-level stage of processing, sensitivity to the direction of motion should not be influenced by the allocation of attention. A preliminary experimental result using only two people indicated that the former is the case. If this result is confirmed with additional people, it will indicate that attention can influence even very primitive stages of visual information processing, leading to the conclusion that feedback projections play a very important role in making visual perception active and influenced by high-level cognitive functions, rather than entirely passive and automatic. These results should have important implications for the design of computer vision systems, a very difficult computer problem. ***