Mechanisms of Motion Detection in Retinal Neural Network

摘要 对运动物体的检测是一种视网膜功能，它对动物的生存至关重要。多个神经元， 视网膜中的神经网络已被确定为这项任务的关键参与者，包括星爆无长突神经网络。 细胞（SAC）和方向选择性神经节细胞（DSGCs），它们感知运动方向。最近的研究 已经揭示了双极细胞和无长突细胞之间的几个神经网络参与了方向， 选择性然而，环境因素对这些神经元的运动敏感性调谐的影响并不明显。 很好理解。背景景物影响目标运动神经元的增益控制和调谐 然而，我们刚刚开始了解这些神经元的敏感性和适应性。的 本项目的长期目标是了解视网膜中的细胞和分子机制 用于感测运动方向。我们将进行膜片钳记录，双光子钙成像， 免疫组织化学、计算机模拟和行为学研究，以检查机制 潜在的方向选择性。我们以前发现，从SAC到双极细胞的胆碱能反馈 有助于SAC方向选择性。我们现在有证据表明，胆碱能反馈被转移到 长距离和调谐SAC方向选择性。因此，我们假设传入对象发送一个 通过胆碱能途径向双极细胞发出信号，以调节SAC方向选择性，这是一种预测 编码我们提出了两个具体的目的来研究长距离胆碱能反馈。我们将测试这个 通过记录双极细胞中的长距离胆碱能反馈（Aim 1），我们将研究 双极细胞轴突终末、SAC树突和DSGC中长距离胆碱能反馈的结果 活动（目标2）。视觉预测是运动检测的一个重要特征，它会减少神经信号 延迟和促进动物反应。从该项目的结果中获得的知识将有助于了解 视网膜中的运动检测和视觉信号处理的附加层。

Abstract Detection of moving objects is a retinal function which is crucial for an animal's survival. Multiple neurons and neural networks in the retina have been identified as critical players in this task, including starburst amacrine cells (SACs) and direction-selective ganglion cells (DSGCs), which sense direction of motion. Recent studies have revealed that several neural networks among bipolar and amacrine cells are involved in direction selectivity. However, the impact of environmental factors on motion sensitivity tuning of these neurons is not well understood. Background scenery affects the gain control and tuning of neurons for object motion detection; however, we have just begun to understand the sensitization and adaptation of those neurons. The long-term objective of the present project is to understand the cellular and molecular mechanisms in the retina for sensing direction of motion. We will conduct patch clamp recordings, two-photon calcium imaging, immunohistochemistry, computational simulation, and behavioral studies to examine the mechanisms underlying direction selectivity. We previously found that cholinergic feedback from SACs to bipolar cells contributes to SAC direction selectivity. We now have evidence that the cholinergic feedback is transferred for a long distance and tune SAC direction selectivity. Therefore, we hypothesize that an incoming object send a signal to bipolar cells through a cholinergic pathway to tune SAC direction selectivity, a form of predictive coding. We propose two Specific Aims to investigate long-distance cholinergic feedback. We will test this hypothesis by recording long-distance cholinergic feedback in bipolar cells (Aim 1), and we will examine the outcome of the long-distance cholinergic feedback in bipolar cell axon terminals, SAC dendrites, and DSGC activity (Aim 2). Visual prediction is an essential feature for motion detection, which would reduce neural signal delays and facilitate the animal reaction. Knowledge gained from the results of this project will shed light on the additional layer of motion detection and visual signal processing in the retina.