Integrating top-down signals in face and object processing

当我们谈论“看世界”时，我们含蓄地指的是与我们期望找到它们的地方相关的人和事。我们可能认为这些能力是理所当然的，但工程师们还没有建立一个合成的视觉系统，它的性能与我们的视觉系统一样准确，速度和效率。我的研究致力于了解大脑如何编码面部和物体。一个尚未解决的问题是，脑细胞的活动及其相互作用如何导致我们的视觉能力。我们的视觉系统成功的一个秘密可能是我们使用两种自我生成的信号来增强面部和物体的处理：（i）我们主动扫描环境的眼球运动，以及（ii）来自以前经历的记忆。我们将记录当人脸和物体被检测或辨别时脑细胞群的活动。我们将测量动作电位速率的变化以及这些变化如何在细胞中分布，以及动作电位是否“跟随”局部神经节律的节拍，或者独立于它们而起作用。此外，（i）我们将确定这种代码如何受到主动搜索动态的影响，主动搜索每秒将新的视觉信息放置在视网膜上约3-5次。各就各位预备回应“去吧！“当你是那个发号施令的人的时候会快得多同样，大脑是否可以利用它产生的眼球运动来帮助视觉系统为来自视网膜的传入信号做好准备？(ii)另一种准备或塑造大脑活动的方法是通过记忆。我们在杂乱的环境中更容易找到我们熟悉的东西，而不是偶然发现别人的东西，我们更容易认出一个熟悉的朋友，而不是一个新认识的人。经验会对我们的感知能力产生巨大的影响。我们将研究眼球运动和过去的经验对细胞神经活动的影响，这些细胞对面孔或物体做出反应。了解面孔和物体在大脑中是如何编码的，以及它是否可以被塑造成更好的表现，是一个基本的问题，可以改变我们对大脑处理的看法，并为人工系统提供信息，试图模仿我们“看世界”的非凡能力。

When we talk about "seeing the world", we implicitly refer to the people and things associated with the places where we expect to find them. We may take these abilities for granted, but engineers have yet to build a synthetic visual system that performs as accurately, with the level of speed and efficiency as our visual system. My research is devoted to understanding how the brain codes faces and objects. One unresolved question is how the activity of brain cells and their interactions lead to our visual aptitudes. One secret to our visual system's success may be our use of two self-generated signals to enhance face and object processing: (i) our eye movements that actively scan the environment, and (ii) memory from previous experiences. We will record the activity of groups of brain cells as faces and objects are detected or discriminated. We will measure the changes in the rate of action potentials and how the changes are distributed across cells, as well as whether action potentials 'march to the beat' of local neural rhythms, or act independently of them. Furthermore, (i) we will determine how this code is influenced by the dynamics of active search, which places new visual information on the retina ~3-5 times per second. "On your mark, get set"...reacting to "Go!" is much faster when you're the one calling the shot. Similarly, could the brain use the eye movement it generated to help prepare the visual system for incoming signals from the retina? (ii) Another way to prepare or shape brain activity is through memory. We find objects in clutter better when it's our familiar clutter than when we stumble upon someone else's, and we have an easier time recognizing a familiar friend than a new acquaintance. Experience can have a dramatic impact on our perceptual abilities. We will study the influence of eye movements and of past experience on neural activity in cells that respond to faces or objects. Understanding how faces and objects are coded in the brain, and if it may be shaped for better performance, is a fundamental question that could change our views of brain processing in general, and inform artificial systems that seek to emulate our remarkable ability to "see the world".