Effects of saccade-like image shifts on retinal processing: Phenomena, mechanisms, and relation to visual processing in higher brain centers

在自然观察期间，视网膜上的图像流主要由观察者的行为决定。在这方面，主动视觉探索期间的眼球运动特别占主导地位，特别是因为它们每秒持续发生3-5次。尽管如此，在过去，视网膜图像处理往往是孤立的刺激，忽视了高度动态方面的自然viewing.In这个项目中，我们将探讨眼动引起的图像运动对视网膜信号处理的影响。我们将详细描述视网膜中与扫视相关的反应调制，并将视网膜输出中观察到的效应与视网膜受体脑区中描述良好的现象相关联。重要的是，我们将研究视网膜中扫视反应调制的细胞机制。基于初步的数据，我们预计，视网膜反应的“测试刺激”的背景下，眼跳将强烈调制的反应相比，相同的刺激单独提出。此外，我们将表明，扫视渗出其调节作用长达1秒，这表明在自然条件下，与短的扫视间固定的眼动诱导的效果高度相关的作用。重要的是，我们将表明，眼跳相关的视网膜调制严重依赖于统计特性的背景场景中存在的眼跳，周围的亮度水平，并在特定的视网膜细胞类型。例如，在扫视后，OFF神经节细胞的反应可以被正向调节，但ON神经节细胞的反应不被正向调节。这表明视网膜内的不同通路在扫视调制的性质方面是不同的。因此，从更高的视觉区域已知的调制的多样性可能，至少部分，是由在视网膜中看到的调制的多样性造成的。这个项目是独特的，因为它将调查视网膜信号处理在自然观看的条件下，同时采取综合的眼光扫视启动的视觉神经元从视网膜到大脑的反应调制。

During natural viewing, image flow on the retina is determined primarily by the behavior of the observer. Eye movements during active visual exploration are particularly dominating in this regard, especially because they incessantly occur 3-5 times per second. Despite this, retinal image processing has in the past often been studied with isolated stimuli, ignoring the highly dynamic aspects of natural viewing.In this project, we will explore the effects of eye-movement induced image motion on signal processing in the retina. We will characterize saccade-related response modulations in the retina in great detail, and we will correlate the effects seen in the retinal output to well-described phenomena in retina-recipient brain areas. Importantly, we will investigate the cellular mechanisms underlying saccadic response modulation in the retina. Based on preliminary data, we anticipate that retinal responses to "test stimuli" presented in the context of saccades will be strongly modulated in comparison to responses to the same stimuli presented in isolation. Moreover, we will show that saccades exude their modulatory effects for up to 1 second, suggesting a highly relevant role of eye-movement induced effects under natural conditions with short inter-saccadic fixations. Importantly, we will show that saccade-related retinal modulation critically depends on the statistical properties of the background scene present during the saccade, on the ambient luminance level, and on the specific retinal cell type. For example, the responses of OFF ganglion cells, but not ON ganglion cells, can be positively modulated after saccades. This suggests that the different pathways within the retina are distinct with respect to the properties of saccadic modulation. Thus, the diversity of modulations known from higher visual areas might be, at least in part, caused by the diverse modulations seen in the retina.This project is unique in that it will investigate retinal signal processing under conditions of natural viewing, while taking an integrated look at the saccade-initiated response modulation of visual neurons from retina to brain.