Signal Processing in the Inner Retina

视网膜内层的信号处理

• 批准号: 7617045
• 负责人: Steven H DeVries
• 金额: $ 33.98万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-07 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7617045
• 关键词: AMPA Receptors; Action Potentials; Amacrine Cells; Brain; Cells; Characteristics; Childhood; Disease; Elderly; Employee Strikes; Feedback; Felis catus; Goals; Inner Plexiform Layer; Investigation; Laboratories; Light; Macular degeneration; Mammals; Measurement; Mediating; Oryctolagus cuniculus; Pathway interactions; Photoreceptors; Play; Primates; Property; Publishing; Rattus; Research Personnel; Rest; Retina; Retinal; Retinal Cone; Retinal Ganglion Cells; Retinitis Pigmentosa; Role; Signal Transduction; Spermophilus; Synapses; Testing; Vision; Visual; Work; analog; base; computerized data processing; ganglion cell; postsynaptic; programs; research study; response; retinal rods; spatiotemporal; voltage

DESCRIPTION (provided by applicant): Under daylight conditions, vision depends on cone photoreceptors and the cone-driven retinal circuitry. Cone photoreceptors are susceptible to damage or destruction during diseases of both childhood (e.g., retinitis pigmentosa) and in the elderly (e.g., macular degeneration). An appreciation of the abnormalities in cone-mediated vision caused by these diseases depends upon our understanding of the function of cone circuits in the normal retina. Most common laboratory mammals (e.g., rat and rabbit) have rod-dominant retinas and are less-suitable for investigations of the circuitry underlying cone-mediated vision. As an alternative, we have pioneered the use of the ground squirrel retina, in which up to 95% of the photoreceptors are cones, and in which the postsynaptic bipolar cells are plentiful and easy to access for detailed electrophysiological measurements. A flash of light generates an "analog" signal in cone photoreceptors that is graded with intensity and relatively sustained in duration. The signals in cone photoreceptors are then divided into two functional pathways at the cone to bipolar cell synapse: On-center and Off-center. We have shown, both in published work and in the Preliminary Results, that On and Off bipolar cells each can be further subdivided according to the temporal characteristics of their signals. Thus, of the ~4 anatomically distinct types of ground squirrel On bipolar cells, only one (the b5) can signal at light-on with an all-or-nothing Na+ action potential. Similarly, 1 of the ~4 types of Off bipolar cells (the b2) has fast AMPA receptors and can produce a rebound depolarization at light-off. Given their transient light responses, our goal is to test whether the b5 and b2 cells drive classes of retinal ganglion cells that produce transient responses at either the onset or offset of a step of light. Specifically, we will determine a) whether b5 and b2 cells costratify and make anatomical contacts with On and Off transient cells in the inner plexiform layer; b) whether b5 and b2 cells provide a transient synaptic input to the transient ganglion cells; and, c) and whether b5 and b2 cells cause the transient spike responses in On and Off transient ganglion cells.

描述（由申请人提供）：在日光条件下，视力取决于锥形感受器和锥体驱动的视网膜电路。锥形感受器易受儿童期（例如色素性视网膜炎）和老年人（例如黄斑变性）的疾病期间的损害或破坏。这些疾病引起的锥体介导视力异常的欣赏取决于我们对正常视网膜中锥电路功能的理解。大多数常见的实验室哺乳动物（例如，大鼠和兔子）具有杆源性视网膜，不适合研究锥体介导的视力下的电路。作为替代方案，我们率先使用了地松鼠视网膜的使用，其中高达95％的光感受器是锥体，其中突触后双极细胞丰富且易于访问详细的电生理测量。 光线闪光在锥形感光器中产生一个“模拟”信号，该信号以强度和相对持续的持续时间进行分级。然后将锥形光感受器中的信号分为两种功能途径，在锥体下到双极细胞突触：中心和中心。我们已经在发表的工作和初步结果中都表明，双极细胞都可以根据其信号的时间特征进一步细分。因此，在双极细胞上〜4种〜4种不同类型的地松鼠类型中，只有一个（B5）可以用全或全部不含有的Na+动作电位发出信号。同样，〜4种〜4种类型的OFT双极细胞（B2）中有1种具有快速的AMPA受体，并且可以在轻开口时产生反弹去极化。鉴于它们的瞬时光反应，我们的目标是测试B5和B2细胞是否驱动视网膜神经节细胞的类别，这些视网膜神经节细胞会在光步的发作或抵消时产生瞬态响应。具体而言，我们将确定a）B5和B2细胞是否具有特征性并与内和关闭瞬时层中的瞬时细胞进行解剖接触； b）B5和B2细胞是否为瞬态神经节细胞提供了短暂的突触输入； c）以及B5和B2细胞是否引起瞬态神经节细胞内和关闭瞬态尖峰响应。