Objects in Scenes - How scene structure shapes visual object representations

在日常生活中，我们的视觉环境是非常复杂的，由大量不同的物体组成。这些物体不会出现在空间中不可预测的位置，但会依附于典型的、经常遇到的位置结构。例如，灯通常挂在天花板上，而我们预计会看到地板上的地毯。在这种高度可预测的位置看到物体的大量体验，会影响视觉系统处理物体的方式吗？在这里，我提出，物体位置的重复规则塑造了视觉处理通道，这些通道被优化为有效地对出现在视野特定部分的特定物体进行编码。在这个项目中，我将使用行为实验以及fMRI和EEG记录的组合来测试从这一建议得出的两个关键预测：(1)对象信息在整个视野中非均匀分布，当对象出现在它们的典型位置时，它们的编码效率更高。因此，与非典型定位的对象(例如，下视野中的灯)相比，通常定位的对象(例如，上视野中的灯)应该被更准确地感知，并且它们的表示在神经级别上应该更好地区分。(2)视觉皮层中个体对象表征的相似性部分取决于真实世界的结构，因此与相似位置相关的对象被相似地编码。因此，视觉皮质中的表征相似性应该可以通过典型的对象到对象的距离来解释(例如，灯应该更类似于桌子而不是地毯)，即使对象是集中和独立呈现的。沿着视觉层次的位置特异性加工通道的想法表明，典型空间结构的影响可以在最初的物体加工时间附近的物体选择性视觉皮质中观察到。FMRI和EEG的结合允许测试这一预测，因为它可以准确地揭示对象视觉的时空动态如何与我们日常环境的结构属性相关。该项目的结果可以表明，只有在真实世界环境及其位置结构的上下文中才能完全理解视觉对象表示。此外，这些新颖的见解可以解释对自然场景的有效感知，自然场景包含大量不同但有规则结构的对象。

In everyday situations, our visual environments are highly complex, consisting of a multitude of different objects. These objects do not appear in unpredictable locations in space, but adhere to typical, frequently encountered positional structures. For example, lamps are commonly hanging from the ceiling, while we expect to see carpets on the floor. Does the massive experience with objects seen in such highly predictable locations influence the way in which objects are processed in the visual system? Here, I propose that recurring regularities in object positions shape visual processing channels that are optimally tuned for efficiently coding specific objects appearing in specific parts of the visual field. In this project, I will use behavioral experiments and a combination of fMRI and EEG recordings to test two key predictions derived from this proposal: (1) Object information is non-uniformly distributed across the visual field, with objects being coded more efficiently when they appear in their typical locations. As a consequence, typically positioned objects (e.g., a lamp in the upper visual field) should be perceived more accurately and their representations should be better discriminable on a neural level - as compared to atypically positioned objects (e.g., a lamp in the lower visual field). (2) The similarity of individual object representations in visual cortex is partly determined by real-world structure, so that objects associated with similar locations are coded similarly. Hence, representational similarity in visual cortex should be explicable by typical object-to-object distances (e.g., a lamp should be more similarly represented to a table than to a carpet), even when the objects are presented centrally and in isolation. The idea of location-specific processing channels along the visual hierarchy suggests that the effects of typical spatial structure can be observed in object-selective visual cortex around the time of initial object processing. The combination of fMRI and EEG allows for testing this prediction, as it can precisely reveal how the spatiotemporal dynamics of object vision are related to the structural properties of our everyday environments. The results of the project can indicate that visual object representations can only be fully understood in the context of real-world environments and their positional structure. Furthermore, these novel insights can provide an explanation for the efficient perception of natural scenes, which contain a large amount of different - but regularly structured - objects.