High-level visual adaptation: exploring the neural representation of faces, words and objects

适应是心理学中用来研究大脑如何表现视觉元素和物体的一种技术。这包括让一个人在一段确定的时间内研究一个视觉对象——适应性刺激，然后显示一个测试刺激。适应性刺激改变了对测试刺激的感知，这种效应通常归因于被适应性刺激激活的神经元的疲劳或习惯化。因此，在瀑布效应中，观看水流持续向下运动的瀑布会使编码向下运动的神经元习惯，当被试看到静止的图像时，疲劳的向下神经元和未受影响的向上神经元之间的不平衡会使静止的图像看起来是向上漂移的。***这项技术最近被用来检查我们是如何编写面部代码的。即使只是短暂地观看一张正在适应的脸5秒钟，也会改变对后续测试脸的感知。通过分离面部的特定属性并保持其他属性不变，这已被用于研究我们如何表征面部身份、表情、性别、年龄等，并揭示视觉系统编码的面部特定属性。在过去的7年中，我们的实验室在这一领域做出了重大贡献。在目前的提案中，我们的目标是利用我们在面部适应方面发展起来的专业知识，将类似的技术应用于其他物体表征的研究，特别是我们的大脑如何表征视觉单词。与其他物体不同，人脸被认为是一种特殊类型的视觉刺激，几乎所有人都有这种特殊的技能。这是否使它们不同于其他物体是一个有争议的问题。然而，有了兴趣和接触，就有可能发展对其他物体的专业知识，比如汽车和鸟类。一个有趣的问题是，人们对这些物体形成的表征是否会获得与人脸相似的属性。适应是解决关于视觉专家本质的问题的一种方法，成为“视觉专家”意味着什么。***我们对单词特别感兴趣，因为这也是许多（有文化的）人都擅长的领域，但成像研究表明，虽然他们确实使用大脑的相似部分，但单词更多地涉及左半球，而面孔主要涉及右半球。我们将使用适应性来解决这样一个问题：单词表示中的哪些类型的视觉信息与面孔相似——表明由视觉专业知识产生的共同属性——以及哪些类型显示出重要的差异。这些差异将有助于我们理解“半球特化”，即大脑左右半球的视觉编码是如何不同的

Adaptation is a technique used in psychology to study how the brain represents visual elements and objects. This involves having a person study a visual object - the adapting stimulus - for a defined period of time, following which a test stimulus is shown. The adapting stimulus alters the perception of the test stimulus, an effect that is often attributed to fatigue or habituation of the neurons that were activated by the adapting stimulus. Thus, in the waterfall effect, watching a waterfall with continuous downward movement of water will habituate neurons that code for downward motion, and when the subject is then shown a stationary image, the imbalance between fatigued downward neurons and unaffected upward neurons will cause the stationary image to appear to be drifting upwards.***This technique has recently been used to examine how we code faces. Even a brief view of an adapting face for 5 seconds will alter the perception of a subsequent test face. By isolating specific properties in the face and keeping others constant, this has been used to study how we represent facial identity, expression, gender, age and so on, and to reveal specific properties that the visual system encodes about faces. Our laboratory has made significant contributions in this field over the last 7 years. In the current proposal, we aim to use the expertise we have developed with face adaptation to apply similar techniques to the study of other object representations and in particular, how our brains represent visual words. ***Unlike other objects, faces are held to be a particular type of visual stimulus for which nearly all humans have a special expertise. Whether this makes them different from other objects is a matter of debate. However, it is possible with interest and exposure to develop expertise for other objects, such as cars and birds. One interesting question is whether the representations that people develop for these other objects then acquire properties that make them similar to faces. Adaptation is a means of addressing this question about the nature of visual expertise, what is means to be a "visual expert".***Words are of particular interest because they are also a class for which many (literate) humans have expertise, but imaging studies show that, while they do use similar parts of the brain, words involve the left hemisphere more while faces involve the right hemisphere mainly. We will use adaptation to address the question about what types of visual information in representations of words are similar to faces - indicating common properties generated by visual expertise - and what types show important differences. Differences would be important in contributing to our understanding of "hemispheric specialization", how the visual coding of the right and left hemispheres of the brain differ.**