Correlates of perceived size in V1 neurons

描述（由申请人提供）：该项目的目标是使用行为和单单元记录技术来理解三维（3D）环境在物体大小的神经处理中的作用。估计物体的大小突出了视觉中一个基本的计算问题：视网膜图像固有的模糊性。对于任何给定的视网膜图像，都有无数的物体大小和观看距离的组合可以产生该图像。一个基本的挑战是理解如何将距离信息（在视网膜图像中没有明确表示）与视网膜尺寸信息相结合，以实现物体尺寸的准确和稳定表示。这一建议的总体框架是，距离信息与视网膜大小信息在视觉系统的早期阶段相结合。来自人类行为、功能磁共振成像和ERP实验的证据表明，物体的大小是在初级视觉皮层中表征的。这些结果与初级视觉皮层被动地反映视网膜上的刺激不一致，而是表明与3D场景解释相关的高级信号可能被反馈到初级视觉皮层，以调整分配给视觉对象的组织数量。为了扩展这些发现，我们提出的实验在动物模型中使用心理物理测量和单神经元电生理记录来追求这些结果。提出了两个具体目标：1)单单元记录，以研究单个视觉皮层神经元的感受野结构随3D环境的变化；2)在特定目标中使用的同一动物模型中测量尺寸错觉的心理物理测量。总之，这些具体目标将阐明大小感知的基础过程，这对于与3D世界的互动至关重要，并将在人类和非人类受试者的视觉研究之间架起一座桥梁。

DESCRIPTION (provided by applicant): The goal of this project is to use behavioral and single-unit recording techniques to understand the role of three-dimensional (3D) context in the neural processing of object size. Estimating the size of an object highlights a fundamental computational problem in vision: the inherent ambiguity in the retinal image. For any given retinal image there are an infinite number of combinations of object sizes and viewing distances that could give rise to that image. A fundamental challenge is to understand how distance information - which is not explicitly represented in the retinal image - is combined with retinal size information to achieve an accurate and stable representation of object size. The overarching framework of this proposal is that distance information is combined with retinal size information in early stages of the visual system. Convergent evidence from behavioral, fMRI, and ERP experiments in humans have shown that object size is represented in the primary visual cortex. These results are inconsistent with the primary visual cortex passively reflecting the stimulus on the retina, but rather suggest that high-level signals related to 3D scene interpretation may be fed back to primary visual cortex to adjust the amount of tissue allocated to represent visual objects. To extend these findings, our proposed experiments pursue these results in an animal model using psychophysical measurements and single-neuron electrophysiological recordings. Two specific aims are proposed: 1) single-unit recording to investigate the changes in receptive field structure of individual visual cortical neurons as a function of 3D context and 2) psychophysical measurements of size illusions in the same animal model used in specific aim 1. Together these specific aims will shed light on the processes that underlie size perception, which are critical for interacting with a 3D world, and will provide a bridge between vision studies in human and non-human subjects. PUBLIC HEALTH RELEVANCE: The relevance of this project is that we will gain further understanding into how the brain constructs visual perceptions of the environment. This process is a complex interaction between the light signal that arrives at the eye and our built- in, implicit knowledge about the structure of the environment. This understanding is essential for identifying how the visual system develops and for finding potential treatments for visual impairments in response to brain injury or disease.