Function and Plasticity in a Mapped Sensory System

在大脑中，感觉系统通常显示出空间映射 感官刺激的特性。 在这样的“映射”中， 邻近的神经细胞显示出系统性的变化， 反应，或“调谐”，每个细胞对某些特定的 感觉参数，如声音的音高或 视觉栏的方向。 目前还不清楚 这种高度具体的地图的发展，也不如何发展， 取决于经验。 这个项目使用了一个相对简单的昆虫神经的一部分 系统具有生理特征， 可识别的神经元 蟋蟀有一对感觉器官 在它的尾部有一个叫做尾须的附属物。 每个尾椎都非常 对空气传播的声音和振动敏感， 信号传递到中间神经元启动的中央神经节 适当的运动行为，如逃跑。 细胞外和 细胞内记录和染料填充将与 复杂的共聚焦显微镜和计算机重建 传入投射，它们的突触部位， 目标中间神经元的形态。 解剖图将是 利用编码风的单个神经元的投影 速度和风向。 这张地图预测了 应该发生在系统中的一个特定的刺激，并将 在生理测试中通过活性依赖性染料进行测试。 目的是描述结构和功能 这个定义明确的，地形映射的感官组织 系统 这张地图的发展将追溯到年轻的 阶段，与成人地图进行比较，看看是否 在发育过程中发生功能性变化。 这种新方法的结果将对许多领域产生影响 感觉和发育神经科学，通过澄清 这种广泛映射原理的细胞机制。

Within the brain, sensory systems often show an spatial mapping of sensory stimulus properties. In such a "map" an array of neighboring nerve cells shows a systematic variation in the responsiveness, or "tuning", of each cell to some particular sensory parameter, such as the pitch of a sound or the orientation of a visual bar. It is not yet understood just how such highly specific maps develop, nor how that development may depend on experience. This project uses a part of a relatively simple insect nervous system that has physiologically characterized and individually identifiable neurons. The cricket has a pair of sensory appendages, called cerci, at its rear end. Each cercus is very sensitive to airborne sounds and vibrations, and sends sensory signals to a central ganglion where interneurons initiate appropriate motor behavior such as escape. Extracellular and intracellular recordings and dye-filling will be used with sophisticated confocal microscopy and computer reconstruction of the incoming afferent projections, their synaptic sites, and the morphology of the target interneurons. An anatomical map will be constructed using projections of single neurons that encode wind velocity and wind direction. This map predicts where activity should occur in the system for a particular stimulus, and will be tested by activity-dependent dyes during physiological tests. The objective is to describe the structural and functional organization of this well-defined, topographically mapped sensory system. The development of this map will be traced from younger tages, to compare to the adult map, and to see whether functional changes occur during development. Results from this novel approach will have impact on many areas of sensory and developmental neuroscience, by clarifying the cellular mechanisms of this widespread mapping principle.