Deciphering the elemental building blocks of visual appearance

视觉是一系列复杂的生理和生理事件的产物。虽然视觉通路的一些孤立阶段已经被很好地理解，但研究物理刺激和感知之间的直接联系仍然是视觉科学的挑战之一。在人类中，视网膜感光体马赛克的激活构成了视觉信号的细胞入口点。分离单个细胞对整体感知的贡献是困难的，因为在正常的观看中，在任何给定的时刻，数以万计的光感受器都受到刺激。此外，光学缺陷和眼睛的持续运动阻碍了精确的实验访问。然而，自适应光学微刺激的最新进展，现在可以针对活体视网膜中的单个感光细胞进行分离功能测试。在这里，我们询问每个单独的光感受器对视觉感知的贡献程度，以及基本细胞信号是否也实例化了感知元素。只有一个光感受器是什么样子的？当刺激更复杂时，这些基本感知是如何结合和相互作用的？我们将通过直接映射高度控制的单个（和多个）细胞刺激及其引发的主观表象来解决这些问题。虽然单细胞刺激与外观之间的微观映射迄今为止是完全未知的，但在宏观层面上，也缺乏对刺激与外观之间关系的理解，即空间扩展刺激的更自然状态。其中一个原因是，到目前为止，大部分视觉研究都是使用视觉灵敏度或灵敏度等性能指标来研究视觉刺激被检测或辨别的程度，而不是研究它们在主观上的表现。然而，为了理解视觉空间感知的潜在机制，对系统的中心输出之一——视觉外观——有一个精确的描述是很重要的。在这里，我们将结合视觉外观的微观和宏观捕获，从中央凹的单个锥体到外围的大锥体阵列。为此，我们将开发新的程序来准确量化主观外观，并将这些方法应用于许多已知可以改变刺激外观的范式。通过将尖端的高分辨率光学刺激技术与新颖的基于外观的心理物理方法相结合，在大范围的行为实验中，我们旨在揭示视觉空间感知的基本组成部分。

Seeing is a product of a complex physical and physiological chain of events. While some isolated stages of the visual pathway are well understood, studying the direct link between the physical stimulus and perception remains one of the challenges in vision science. In humans, the activation of the retinal photoreceptor mosaic constitutes the cellular entry point of the visual signal. To isolate the single cell contribution to the overall percept is difficult, because in normal viewing, tens of thousands of photoreceptors are stimulated at any given moment. Moreover, precise experimental access is hindered by the optical imperfections and the constant movement of the eye. Recent advances in adaptive optics micro-stimulation, however, now make it possible to target single photoreceptor cells in the living retina for isolated function testing.Here, we ask in how far each individual photoreceptor contributes to the visual percept and if elemental cellular signals also instantiate perceptual elements. How does it look to see with only a single photoreceptor, and how do these elemental percepts combine and interact when stimuli are more complex? We will tackle these questions by direct mapping of highly controlled single (and multiple) cell stimulation and the subjective appearances they elicit. While the microscopic mapping between single cell stimulation and appearance is to-date entirely unknown, there is also a lack of understanding of the relation between stimulus and appearance on a macroscopic level, i.e. the more natural condition of spatially extended stimuli. One reason is that by far the largest part of vision research uses performance measures, like visual acuity or sensitivity, to study how well visual stimuli can be detected or discriminated, but not how they appear subjectively. To understand the underlying mechanisms of visual space perception, however, it is important to have a precise account of one of the central outputs of the system — visual appearance. Here, we will combine micro and macro captures of visual appearance, all the way from the single cone in the fovea to large arrays of cones in the periphery. To this end, we will develop novel procedures to accurately quantify subjective appearance and apply these methods in a number of paradigms that are known to alter stimulus appearance. By combining cutting-edge high-resolution optical stimulation techniques with novel appearance-based psychophysical methods in a large range of behavioral experiments, we aim to uncover the elemental building blocks of visual space perception.