Mechanismen underlying visual search in barn owls.

视觉搜索是人类和动物的一种认知能力。在视觉搜索过程中，注意力被环境中的显著刺激所吸引。在实验室研究中，观察者被要求在包含许多干扰物的场景中搜索目标物。在简单的搜索任务中，搜索时间和固定次数并不取决于所呈现的其他项目的数量。因此，这种搜索也被称为并行搜索或特征搜索。据说目标会跳出来。我们最近在行为层面上表明，仓鸮有一种弹出效应，类似于人类。现在我们打算研究仓鸮视觉搜索机制的神经基础，并进一步将仓鸮的行为与人类的行为进行比较。具体来说，我们建议记录醒着的猫头鹰在受到视觉搜索模式刺激时的神经活动。我们期望在仓鸮的前脑中找到对特征搜索刺激敏感的神经元。当目标与干扰物的方向相同时，当目标与干扰物的方向不同时，这些神经元的反应会有所不同。同样的实验将在镇静的、被动观察的猫头鹰身上进行，以观察主动行为对神经反应的影响。此外，我们想使用最近在人类身上测试的刺激范式，看看猫头鹰对这些刺激的反应是否与人类相似。所有这些实验都是为了增加我们对进化如何塑造大脑以应对复杂视觉环境的认识。

Visual search is a cognitive ability of humans and animals. During visual search attention is attracted to salient stimuli in the environment. In laboratory research observers are asked to search a target item in a scene containing many distracter items. In easy search tasks, search time and number of fixations do not depend on the number of other items presented. Therefore, such a search is also called parallel or feature search. The target is said to pop out. We have recently shown on the behavioral level that barn owls have a pop-out effect, similar to what is known from humans. Now we propose to study the neural basis of visual-search mechanisms in the barn owl and to further compare the behavior of barn owls with that of humans. Specifically we propose to record neural activity from awake, actively fixating owls while they are stimulated with visual-search patterns. We expect to find neurons in the forebrain of the barn owls that are sensitive to feature-search stimuli. The response of such neurons would differ in a situation when the target has the same orientation as the distracters and when it has a different orientation than the distracters. The same experiments will be done in sedated, passively viewing owls to see what difference an active behavior makes in the neural responses. Furthermore, we want to use stimulus paradigms recently tested in humans to see whether owls react to these stimuli similarly as humans do. All in all these experiments are intended to increase our knowledge about how evolution has shaped brains to cope with complex visual environments.