Mechanisms of Synaptic Processing in the Retina

视网膜突触处理机制

• 批准号: 7623043
• 负责人: William Rowland Taylor
• 金额: $ 38.07万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7623043
• 关键词: Affect; Amacrine Cells; American; Back; Biomedical Engineering; Blindness; Brain; Buffers; Cells; Characteristics; Clinical; Code; Cods; Color; Complex; Dendrites; Dependence; Development; Devices; Environment; Exhibits; Eye; Eye diseases; Feedback; Ganglia; Glycine; Health; Inner Plexiform Layer; Lateral; Life; Location; Measures; Mediating; Morphology; Motion; Myxoid cyst; Neurons; Neurotransmitters; Noise; Output; Pattern; Peripheral; Photoreceptors; Process; Property; Prosthesis; Relative (related person); Research Personnel; Retina; Retinal; Retinal Ganglion Cells; Role; Signal Transduction; Structure; Synapses; Testing; Vision; Visual; Visual system structure; Work; cell type; cost; detector; feeding; gamma-Aminobutyric Acid; ganglion cell; horizontal cell; information processing; luminance; object motion; outer plexiform layer; postsynaptic; public health relevance; receptive field; receptor; relating to nervous system; research study; response; retinal neuron; statistics; transmission process

DESCRIPTION (provided by applicant): The output from the retina comprises the activity of 10-15 distinct classes of retinal ganglion cells, each optimized for specific spatial and temporal properties. Information transfer over the limited bandwidth available to retinal neurons is optimized by mechanisms that remove redundant information. One hypothesis for such a mechanism is predictive coding, which collects luminance signals from the surrounding regions and subtracts them from the center response, thereby removing correlations, and enhancing the signal-to-noise ratio and transmission of information. We hypothesize that predictive coding can also be implemented by the subtraction of more complex statistics such as contrast, color, motion, or orientation. Surround antagonism, generated first in the outer retina by horizontal cell feed-back onto photoreceptors, propagates to bipolar cells and therefore must be inherent in all ganglion and amacrine cells, but there it is mixed with a surround generated from the inner retina. Feedback from amacrine cells onto bipolar cell terminals and feed-forward from amacrine cells onto a ganglion cell's dendrites endow its surround with non-linear properties. Both outer and inner retinal surrounds are fundamental for the function of vision, but their relative roles are unknown. We pro- pose to test several hypotheses about amacrine and ganglion cell surrounds. We will record from live amacrine and ganglion cells, measure the spatio-temporal extent of their inner and outer retinal surrounds, and using blockers of neurotransmitters GABA and glycine, distinguish between the linear and nonlinear surround properties. We will test the hypothesis that feedback onto a bipolar cell's terminals produces surround inhibition common to more than one postsynaptic ganglion cell type. Second, we will determine which complex receptive field properties unique to a specific ganglion cell type are mediated by feed-forward inhibition. Third, we will study receptive field properties of specific amacrine cell types to determine whether they can convey the nonlinear properties observed in ganglion cells. The experiments will focus on 2 well-characterized concentric ganglion cells, the brisk-transient (BT) and brisk-sustained (BS) cells, and on 2 well characterized complex ganglion cells, the On-Off direction-selective cells (DSGC), and local-edge-detectors (LED), as well as several types of narrow- and wide-field amacrine cell. This work will collect information about retinal structure and function vital to a better understanding of information processing in the visual system and the brain. It will help to understand better how the eye functions, which will help clinical researchers determine what has gone wrong in many types of eye disease and bioengineers in developing prosthetic retinal devices that more closely match the function of the living retina. PUBLIC HEALTH RELEVANCE: Blindness affects millions of Americans and constitutes a significant cost to public and private health sectors. Development of prosthetic devices that can replace the function of the retina is an avenue of treatment that is being actively pursued. This project will elucidate the properties of neural signals in normal retina, which will allow development of prosthetic devices that can better mimic normal retinal function.

描述（由申请人提供）：来自视网膜的输出包括10-15种不同类别的视网膜神经节细胞的活性，每种针对特定的空间和时间特性进行优化。视网膜神经元可用的有限带宽上的信息传输通过去除冗余信息的机制来优化。这种机制的一个假设是预测编码，其从周围区域收集亮度信号并从中心响应中减去它们，从而去除相关性，并增强信噪比和信息传输。我们假设预测编码也可以通过减去更复杂的统计数据来实现，例如对比度，颜色，运动或方向。环绕拮抗作用首先由水平细胞反馈到光感受器上在外层视网膜中产生，传播到双极细胞，因此必须在所有神经节细胞和无长突细胞中固有，但在那里它与内层视网膜产生的环绕物混合。无长突细胞对双极细胞末梢的反馈和无长突细胞对神经节细胞树突的前馈赋予其周围非线性特性。视网膜的外周边和内周边都是视觉功能的基础，但它们的相对作用尚不清楚。本文拟对无长突和神经节细胞周围的几种假说进行检验。我们将记录活的无长突细胞和神经节细胞，测量其视网膜内外周围的时空范围，并使用神经递质GABA和甘氨酸的阻滞剂，区分线性和非线性周围属性。我们将测试的假设，反馈到一个双极细胞的终端产生环绕抑制常见的一个以上的突触后神经节细胞类型。其次，我们将确定哪些复杂的感受野特性独特的特定神经节细胞类型是由前馈抑制介导的。第三，我们将研究特定无长突细胞类型的感受野特性，以确定它们是否可以传达在神经节细胞中观察到的非线性特性。实验将集中在2个良好表征的同心神经节细胞，轻快瞬时（BT）和轻快持续（BS）细胞，和2个良好表征的复杂神经节细胞，开关方向选择性细胞（DSGC），和局部边缘检测器（LED），以及几种类型的窄场和宽场无长突细胞。这项工作将收集有关视网膜结构和功能的信息，这些信息对更好地理解视觉系统和大脑中的信息处理至关重要。它将有助于更好地了解眼睛的功能，这将有助于临床研究人员确定许多类型的眼病和生物工程师在开发更接近活体视网膜功能的人工视网膜设备中出现的问题。与公共卫生的相关性：失明影响着数百万美国人，对公共和私营卫生部门构成了重大成本。开发可以替代视网膜功能的假体装置是正在积极追求的治疗途径。该项目将阐明正常视网膜中神经信号的特性，这将允许开发能够更好地模拟正常视网膜功能的假体设备。