VISION AND INTRARETINAL POTENTIALS

描述(改编自申请者摘要)：本研究项目旨在 从两个基本方面促进我们对视网膜功能的理解 视觉方面：1)对比度处理和2)光线适应。这将是 通过分析双极细胞的光诱发反应完成，水平 虎鳗的细胞、无长突细胞和视锥感光细胞 (Ambystoma Tigrum)，一种为 细胞内记录。这项提议的主要目标是获得一个 更好地理解发生在最初和 视网膜的第二个突触阶段。实验的中心是细胞内。 来自双极细胞的录音。有几个实验是与人类相似的 心理物理学的工作，因此结果可能最终导致新的模型 对比度知觉和光适应方面的临床障碍。 光感受器和双极细胞之间发生了四种转变 反应：1)对弱对比的双极反应被放大。2)一些 双极细胞反转，而其他细胞则保持光感受器的极性 信号，从而将视觉信息分成两个通道以并行 正在处理。3)双极细胞的响应特性存在多样性， 表明分布式编码是双极细胞的中心特征 功能。4)双极细胞表现出很强的中心-周围拮抗作用，因此 作为视网膜图像的空间滤光片。目前的建议是 旨在更深入地了解所有四个转变。 具体实验建议在1)对比的总标题下进行 加工和扩增；2)中心-环绕拮抗。这些措施包括： A)使用正弦调制和异常低对比度的步骤的实验 确定圆锥驱动双极电机的线性和非线性工作范围 细胞、水平细胞和视锥感光细胞，b)突触分析 双极细胞形成开关无长突细胞反应的机制， C)研究前馈通路与反馈通路在调节 双极细胞感受野的环绕及其机制研究 调和大场噪声、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.