Feature and location interactions in visual object processing

这项拟议的项目旨在了解特征和位置偏好在人类视觉对象识别中是如何相互作用的，包括这种相互作用的感知结果及其潜在的神经机制。人类非常擅长识别复杂的视觉物体，尤其是人脸。我们的大脑是如何做到这一点的？视觉识别被认为依赖于下颞叶皮质(IT)的神经处理。IT亚区的神经反应显示出对不同视觉对象类别(如面孔或位置)的明显偏好，传统上被描述为“位置不变”(即，与视觉对象在视网膜上出现的位置无关)。然而，一系列发现指出了刺激位置在物体识别中的作用，并表明IT中的神经元可以具有高度的空间选择性。视觉识别如何在此基础上发挥作用？申请人和对猴子的独立研究的最新发现表明：特征和位置偏好在某种程度上匹配，反映了共同的输入属性。这项拟议的项目将在行为和神经成像实验中测试这一想法，以及它与健康和疾病中面部感知的其他方面的关系。例如，之前的研究结果显示，眼睛和嘴巴最常出现在上视野和下视野中--甚至是在观察者的眼球运动中。此外，当孤立的眼睛和嘴巴出现在各自的典型视野位置时，观察者确实更善于识别它们。这可以解释为神经群体偏爱具有匹配空间偏好的眼睛或嘴巴。这项拟议的项目开发了实验范式来检验这一假说，以及空间和特征敏感性之间的这种相互作用可以解释长期研究的脸部颠倒和面容失认症状(面孔失明)的知觉效应。最后，它将测试这种特征-位置交互是否延伸到手写单词识别，这是一种获得视觉专业知识的视觉对象类型。

The proposed project aims to understand how feature and location preferences interact in visual object recognition in humans, including the perceptual consequences of such interactions and their underlying neural mechanisms. Humans are remarkably good at recognising complex visual objects, especially faces. How do our brains enable this? Visual recognition is thought to rely on neural processing in the inferior temporal cortex (IT). Neural responses of IT subregions show a clear preference for different visual object categories (e.g. faces or places), and are traditionally portrayed as 'location invariant' (that is, independent of where on the retina a visual object appears). However, a range of findings point to a role of stimulus location for object recognition and show that neurons in IT can be highly spatially selective. How can visual recognition work on this basis? Recent findings from the applicant and independent studies in monkeys suggest the following: Feature and location preferences are matched in a way reflecting common input properties. The proposed project will test this idea in behavioural and neuroimaging experiments and how it relates to other aspects of face perception in health and disease. For instance, previous results show that eyes and mouths of faces appear most often in the upper and lower visual field, respectively - even across eye movements of the observer. Furthermore, observers are indeed better at recognising isolated eyes and mouths when they appear at their respective typical visual field position. This could be explained neural populations with a preference for eyes or mouths having a matching spatial preference. The proposed project develops experimental paradigms to test this hypothesis, as well as the ones that such interactions between spatial and feature sensitivity can explain long-studied perceptual effects of turning faces upside down and symptoms of prosopagnosia ('face-blindness'). Finally, it will test whether such feature-location interactions extend to written word recognition, a type of visual object for which visual expertise is acquired.