VISION AND INTRARETINAL POTENTIALS

描述（改编自申请人的摘要）：本研究项目旨在 在两个基本方面推进我们对视网膜功能的理解 视觉方面：1）对比度处理和2）光适应。这将是 通过分析双极细胞的光诱发反应，水平 细胞、无长突细胞和视锥细胞 （Ambystoma tigrinum），一种动物模型，为 细胞内记录该提案的主要目标是获得 更好地理解最初发生的转变， 视网膜的第二突触阶段。实验的中心是细胞内 双极细胞的记录。一些实验与人类 心理物理学的工作，因此结果可能最终导致新的模型， 对比度感知和光适应的临床障碍。 光感受器和双极细胞之间发生四种转换 响应：1）对弱对比度的双极响应被放大。2)一些 双极细胞反转，而另一些则保持感光细胞的极性 信号，从而将视觉信息分成两个通道， 处理. 3)双极细胞的反应特性存在多样性， 这表明分布式编码是双极细胞的一个中心特征， 功能4)双极细胞表现出强烈的中心-周围拮抗作用， 用作视网膜图像的空间滤波器。现时的建议是 旨在更深入地了解所有四个转变。 具体的实验是在1）对比 加工和放大以及2）中心-周围拮抗。其中包括： a）使用正弦调制和对比度异常低的阶跃的实验 确定锥形驱动双极的线性和非线性工作范围 B）突触细胞、水平细胞和视锥光感受器的分析， 双极细胞塑造开-关无长突细胞反应的机制， c）研究前馈与反馈途径在介导 双极细胞感受野的周围和d）机制的研究 介导大视场噪声、环绕对抗和空间分辨率， 双极细胞

DESCRIPTION (Adapted from applicant's abstract): This research project seeks to advance our understanding of the function of the retina in two fundamental aspects of vision: 1) Contrast Processing and 2) Light Adaptation. This will be done by analyzing the light-evoked responses of bipolar cells, horizontal cells, amacrine cells, and cone photoreceptor cells in the tiger salamander (Ambystoma tigrinum), an animal model that offers unique opportunities for intracellular recording. The primary goal of this proposal is to obtain a better understanding of the transformations that take place at the first and second synaptic stages of the retina. The experiments center on intracellular recordings from bipolar cells. Several of the experiments parallel human psychophysical work so the results could eventually lead to new models for clinical disorders in contrast perception and light adaptation. Four transformations take place between the photoreceptor and bipolar cell response: 1) The bipolar response to weak contrasts is amplified. 2) Some bipolar cells invert, while others conserve the polarity of the photoreceptor signal, thus splitting visual information into two channels for parallel processing. 3) There is diversity in the response properties of bipolar cells, indicating that distributed encoding is a central feature of bipolar cell function. 4) Bipolar cells show strong center-surround antagonism and thereby function as spatial filters of the retinal image. The present proposal is designed to obtain a deeper understanding of all four transformations. Specific experiments are proposed under the general headings of 1) Contrast Processing and Amplification and 2) Center-Surround Antagonism. These include: a) Experiments using sinusoidal modulation and steps of unusually low contrast to identify the linear and non-linear operating range of cone-driven bipolar cells, horizontal cells, and cone photoreceptors, b) Analyses of synaptic mechanisms by which bipolar cells shape the response of on-off amacrine cells, c) Studies of the role of feedforward vs. feedback pathways in mediating the surround of the bipolar cell receptive field and d) Studies of the mechanisms mediating large-field noise, surround antagonism, and spatial resolution in bipolar cells.