Correlates of perceived size in V1 neurons

描述(由申请人提供)：本项目的目标是使用行为和单位记录技术来理解三维(3D)背景在物体大小的神经加工中的作用。估计物体的大小突出了视觉中的一个基本计算问题：视网膜图像中固有的模糊性。对于任何给定的视网膜图像，物体大小和观察距离的无限组合都可能产生该图像。一个根本的挑战是理解距离信息--在视网膜图像中没有明确表示--如何与视网膜大小信息相结合，以实现对象大小的准确和稳定表示。这一建议的总体框架是，在视觉系统的早期阶段，距离信息与视网膜大小信息相结合。来自人类行为、功能磁共振和事件相关电位实验的融合证据表明，物体大小代表初级视觉皮质。这些结果与初级视觉皮质被动地反映视网膜上的刺激不一致，而是表明与3D场景解读相关的高水平信号可能被反馈到初级视觉皮质，以调整分配给代表视觉对象的组织的数量。为了扩展这些发现，我们提议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。提出了两个特定的目标：1)单单位记录，以研究单个视觉皮层神经元的接受场结构随3D环境的变化；2)在特定目标1中使用的同一动物模型中的尺寸错觉的心理物理测量。这些特定目标将揭示尺寸知觉的基础过程，这是与3D世界相互作用的关键，并将在人类和非人类受试者的视觉研究之间建立一座桥梁。 与公共健康相关：这个项目的相关之处在于，我们将进一步了解大脑如何构建对环境的视觉感知。这个过程是到达眼睛的光信号和我们内在的、关于环境结构的隐含知识之间的复杂相互作用。这一理解对于确定视觉系统是如何发展的以及寻找应对脑损伤或疾病的视觉障碍的潜在治疗方法是至关重要的。

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.