Functional specialization of foveal visual cortex

项目摘要 尽管对灵长类动物初级视觉皮层（V1）的研究已经进行了几十年，但人们对V1的了解非常少。 在代表视野中心几度的区域中的皮层处理：中央凹。这是 特别值得注意的是，V1的不成比例的大部分专用于中央凹处理，并且 中央凹在人类视觉感知和行为中的“中心”作用。对中央凹V1功能的研究 由于无法以足够的精度跟踪动物的眼睛位置来重建眼睛的位置， 视觉刺激在视网膜上的位置。我们最近开发了一种基于模型的眼动跟踪方法 为了解决这个问题，它可以连续地推断眼睛位置，具有足够的精度来研究中央凹V1 处理.因此，我们建议进行第一次详细的研究，刺激处理中央凹V1。简单 换句话说，目前还不知道研究中心凹外V1的大量工作是否适用于中心凹 V1，以及是否有皮质功能的关键要素，只有可能在中央凹观察。由于 由眼球运动驱动的对中央凹的视觉输入的不同动态， 的视网膜输入，和不同的功能作用，中央凹在视觉感知中发挥作用，我们希望确定 V1功能的根本差异。我们将在偏心率范围内进行多电极记录， 清醒猕猴，和目标分析，以三个方面的视觉加工预计是不同的：（1）调谐 用于视觉的时空元素;（2）调整到双眼视差;以及（3）颜色处理。我们预计 这项研究将揭示中央凹神经元刺激处理的实质性差异， 改变了我们目前对大脑皮层视觉处理的理解。 健康相关性。了解中央凹V1在视觉处理中的独特功能作用将提供 对人类视觉感知是如何构建的关键洞察力，同样也会告知我们对 许多影响中央视觉的疾病的影响。例如，年龄相关性黄斑变性（AMD） 是导致美国60岁及以上人群视力丧失的主要原因。晚期AMD患者的外周血 视力，但在中央凹失去视力，导致严重的困难与广泛的重要任务，需要 高敏锐度视力，包括阅读、书写、驾驶和物体/面部识别。同样， 诸如眼球震颤之类的疾病可以扰乱正常的眼球运动和注视， 影响中央凹视力。更好地理解辅助中心凹视觉的神经功能可能会产生一些见解 研究它们对视觉感知的影响，并可能促进新的治疗策略的发展。

PROJECT SUMMARY Despite decades of research studying primate primary visual cortex (V1), remarkably little is known about cortical processing in the region representing the central few degrees of the visual field: the fovea. This is particularly notable given that a disproportionately large fraction of V1 is dedicated to foveal processing, and the “central” role of the fovea in both human visual perception and behavior. Studies of foveal V1 function have been greatly limited by the inability to track an animal's eye position with sufficient accuracy to reconstruct the position of the visual stimulus on the retina. We have recently developed a model-based eye tracking method to address this problem, which can continuously infer eye position with sufficient accuracy to study foveal V1 processing. We thus propose to perform the first detailed studies of stimulus processing in foveal V1. Simply put, it is not known whether the enormous body of work studying V1 outside the fovea is applicable to foveal V1, and whether there are critical elements of cortical function that only might be observed in the fovea. Due to the different dynamics of visual input to the fovea that are driven by eye movements, the different composition of retinal inputs, and the distinct functional roles the fovea plays in visual perception, we expect to identify fundamental differences in foveal V1 function. We will perform multi-electrode recordings across eccentricity in awake macaque, and target analyses to three aspects of visual processing expected to be different: (1) tuning for spatiotemporal elements of vision; (2) tuning to binocular disparity; and (3) color processing. We expect that this proposed study will reveal substantial differences in the stimulus processing of foveal neurons, potentially transforming our current understanding of visual processing in the cortex. Health Relevance. Understanding the unique functional role of foveal V1 in visual processing will provide critical insight into how human visual perception is constructed, and will likewise inform our understanding of the effects of many disorders that impact central vision. For example, age-related macular degeneration (AMD) is a leading cause of vision loss of Americans 60 and older. Patients with advanced AMD retain their peripheral vision, but lose vision in the fovea, resulting in severe difficulties with a wide range of important tasks requiring high-acuity vision, including reading, writing, driving, and object/facial recognition. Likewise, a range of disorders such as nystagmus can disrupt normal eye movements and fixations, thereby disproportionally affecting foveal vision. A better understanding of neural function subserving foveal vision could yield insights into their effects on visual perception and potentially facilitate the development of novel therapeutic strategies.