Neural computation from retina to visual cortex

描述（由申请人提供）：本研究旨在了解视觉信息是如何在眼睛和大脑中处理的。视觉从视网膜开始，视网膜是眼睛后部的一个复杂的神经元网络，视觉图像在这里被转换成动作电位流，通过视神经纤维传递到大脑。在那里，信号通过丘脑到达视觉皮层，在那里，更大的神经元回路开始运作。最近的研究改变了我们对视网膜的看法：虽然它过去被认为是视觉图像的简单预过滤器，但新的研究结果表明，视网膜可以计算场景的相当特定的特征，并通过许多平行通道将这些特征传递给大脑。拟议中的研究将以这项工作为基础，进一步了解视网膜如何将图像转换为脉冲序列，并研究大脑如何使用视觉场景的代码进行进一步处理。这将在一个结合实验以及理论和计算方法的合作项目中得到解决。具体目的是：(1)将视网膜的各种功能统一在一个共同的数学形式下，并以此发现新的功能；(2)确定我们的大脑如何处理视网膜信号以快速理解新场景；(3)解释为什么我们的视力如此敏锐，因为我们的眼睛从不静止。如果成功，这项研究将在多个方面带来好处。首先，它将扩展我们对像视网膜这样的神经回路可以计算什么的概念，以及信息是如何在其输出中编码的，这是系统神经科学的一个重要目标。其次，它将有助于解决视觉处理的两个谜题，这两个谜题与它惊人的速度和高灵敏度有关。第三，这些领域的进展将使脑科学总体上受益。在视网膜中遇到的许多电路基元在其他大脑区域重复出现，并且可能很好地服务于类似的网络级功能。最后，提高对早期视觉功能的理解可以改变人们对视觉疾病和治疗的看法。例如，现在看来，以前分配给视觉皮层的某些功能已经在视网膜上发生了；如果是这样，那么视网膜功能障碍也可能对视觉体验产生更复杂的影响。相反，在通过电子或遗传假体治疗视网膜变性的努力中，人们需要知道假体应该模仿视网膜功能的哪些方面来支持视觉感知。

DESCRIPTION (provided by applicant): This research aims at understanding how visual information is processed in the eye and brain. Vision begins in the retina, a complex network of neurons in the back of the eye where visual images are converted into streams of action potentials that travel through the fibers of the optic nerve to the brain. There the signals pass through the thalamus to the visual cortex, where much larger circuits of neurons are brought to bear. Recent research has changed our view of the retina: Whereas it used to be considered a simple prefilter for the visual image, new results suggest that the retina computes quite specific features of the scene and conveys those to the brain through many parallel channels. The proposed research will build on this work, both to further our understanding of how the retina converts images into spike trains, and to investigate how this code for visual scenes can be used by the brain for further processing. This will be addressed in a collaborative project that combines experimental as well as theoretical and computational approaches. The specific aims are: (1) to unify diverse functions of the retina under a common mathematical formalism, and use this to discover new functions; (2) to determine how our brain might process retinal signals for rapid understanding of a new scene; (3) to explain how our fine vision can be so acute, given that the eyes are never holding still. If successful, this research will offer benefits on multiple fronts. First, it will expand our notions of what a neural circuit like the retina can compute and how the information is encoded in its output, an important goal of systems neuroscience. Second, it will help resolve two mysteries of visual processing, relating to both its remarkable speed and its high acuity. Third, progress in these areas will benefit brain science in general. Many of the circuit motifs encountered in the retina are repeated in other brain areas, and may well serve similar network-level functions. Finally, an improved understanding of early visual function can change how one thinks about visual diseases and therapy. For example, it now appears that certain functions previously assigned to the visual cortex already happen in the retina; if so, then retinal dysfunction could also have much more elaborate effects on visual experience. Conversely, in efforts to treat retinal degeneration by electronic or genetic prostheses one needs to know which aspects of retinal function the prosthesis should emulate to support visual perception. PUBLIC HEALTH RELEVANCE: This project concerns basic research into the function of the early visual system, from the eye to the visual cortex. It will lead to a better understanding of how we see, specifically which parts of vision are handled by the eye versus the brain. This in turn may improve methods of diagnosis for visual dysfunction. Such an understanding will also aid in the development of visual prostheses designed to replace a degenerated retina.