Adaptation and the coding of visual objects by inferior temporal cortex

描述(申请人提供)：视觉系统已经开发出健壮的机制来解决复杂的对象识别计算问题。猕猴视觉处理系统的最高层--前额叶下皮质(AIT)的神经元对复杂物体的反应是选择性的，对物体识别至关重要。AIT神经元的反应不仅取决于在任何给定时刻遇到的刺激，而且还受到最近刺激(适应)历史的强烈影响。这项建议的总体目标是系统地了解影响AIT神经元适应状态的因素，并确定适应对视觉对象编码的影响。我们对AIT中的适应问题进行了两方面的调查。首先，我们建议将适应作为一种工具来探索AIT中的刺激选择性。在视觉系统的早期阶段(如V1和MT)，对长时间视觉刺激的适应会导致调谐功能的变化，这些变化与知觉的变化相关。这些适应性转变被认为是由于扰乱了影响这些区域调谐的电路而出现的，并为我们提供了对刺激选择性背后的机制的洞察。在AIT中，适应性很强，对形状具有选择性。我们的目的是确定适应是否以及如何改变AIT神经元的刺激选择性。具体地说，我们建议探索适应对各种AIT‘调整’维度的影响，以深入了解这些复杂和鲜为人知的接受场背后的机制。其次，我们的目标是了解适应如何影响自然视觉过程中物体的编码。在自然视觉的时间尺度上，AIT的适应是健壮的和形状选择性的。这表明，适应改变了整个AIT群体的对象编码。特别是，自然的时间图像序列可能会产生强烈的适应效应，从而可能为研究适应在腹侧视觉流中的对象编码中所起的作用提供重要线索。了解物体的神经编码对于深入理解人类的视觉感知和长期记忆至关重要，也是有意义地修复这些大脑过程的破坏或创造可能代表这种破坏的假体所必需的。

DESCRIPTION (provided by applicant): The visual system has developed robust mechanisms to solve the complex computational problem of object recognition. The responses of neurons at the highest level of the macaque visual processing system, anterior inferotemporal cortex (AIT), are selective for complex objects and are critical for object identification. The responses of AIT neurons depend not only on the stimuli encountered in any given moment, but are also strongly influenced by the recent history of stimulation (adaptation). The overall aim of this proposal is a systematic understanding of factors that influence the adaptive state of AIT neurons and to determine the effects of adaptation on the coding of visual objects. Our inquiries into adaptation in AIT are two-fold. First, we propose to use adaptation as a tool to probe stimulus selectivity in AIT. At earlier stages of the visual system (such as V1 and MT), adaptation to prolonged visual stimulation results in shifted tuning functions and these shifts are correlated with shifts in perception. These adaptive shifts are thought to arise as a consequence of disrupting the circuitry that acts to mold tuning in these areas, and have provided insight into the mechanisms underlying stimulus selectivity. In AIT, adaptation is strong and is selective for shape. Our aim is to determine whether and how adaptation changes the stimulus selectivity of AIT neurons. Specifically, we propose to explore the effect of adaptation on a variety of AIT 'tuning' dimensions to gain insight into the mechanisms underlying these complex and little-understood receptive fields. Second, our aim is to understand how adaptation impacts the encoding of objects during natural vision. On the timescales of natural vision, adaptation in AIT is robust and shape-selective. This suggests that adaptation alters object coding across the AIT population. In particular, natural temporal image sequences are likely to produce strong adaptation effects and may thus provide important clues into the role of adaptation in object coding in the ventral visual stream. Understanding the neural coding of objects is critical to a deep understanding of human visual perception and long-term memory, and is needed to meaningfully repair the disruption of these brain processes or to create prosthetics that may stand in for such disruption.