Neural Ensemble Codes in Drosophila Olfaction

新的实验技术被开发出来，通过光， 在体内的神经元的限制群体。这些技术将被用来研究信息 在果蝇的嗅觉系统中进行加工。细胞类型特异性启动子 增强子将以基因编码的光学传感器和效应器为目标， 耦合处理层：1）嗅觉受体神经元，位于感觉表面， 轴突投射到触角叶，脊椎动物嗅球的类似物; 2）局部抑制 触角叶的中间神经元; 3）传递嗅觉信息的投射神经元， 触角叶的蘑菇体，类似的脊椎动物嗅觉皮层;和4）凯尼恩 细胞，蘑菇体的内在神经元。气味诱发的神经活动模式将被可视化 通过光学显微镜在这些基因突出的处理阶段中的每一个， 将跟踪从一个处理阶段到另一个处理阶段的活动。凭借这一创新战略， 核心，三个具体目标针对多层神经网络的基本操作原则， 网络将被解决：1）用于表示气味信息的代码在四个 嗅觉处理阶段，以及与这些代码相关的映射规则，将被表征。2)的 计算起源，物理形式和表达抽象的神经符号的语义内容， 分类和行为内涵将在实验中阐明，联合收割机光学 行为分析成像。这些实验的重点将是神经基板， 附加享乐价（即，气味的吸引力或厌恶性），并通过 体验. 3)具有确定的神经或行为表型的突变，或将 通过选择性光刺激插入到遗传指定的靶神经元中，将用于 干扰神经元生理学;这些干扰在系统水平上的影响将通过以下方式进行分析： 光学成像这为理解蜂窝网络甚至 分子术语，从而超越目前将神经科学划分为 莫查瓦尔、行政部门和系统部门。

Novel experimental technologies were developed to monitor and manipulate, through light, genetically circumscribed populations of neurons in vivo. These technologies will be harnessed to study information processing in the olfactory system of the fruit fly, Drosophila melanogaster. Cell-type specific promoters and enhancers will target genetically encoded optical sensors and effectors to neurons in four synaptically coupled processing layers: 1) To olfactory receptor neurons, which are located at the sensory surface and project axons to the antennal lobe, the analog of the vertebrate olfactory bulb; 2) to local inhibitory interneurons of the antennal lobe; 3) to projection neurons that relay olfactory information from the antennal lobe to the mushroom body, the analog of the vertebrate olfactory cortex; and 4) to Kenyon cells, the intrinsic neurons of the mushroom body. Odor-evoked neural activity patterns will be visualized by optical microscopy at each of these genetically highlighted processing stages, and the propagation of activity from processing stage to processing stage will be traced. With this innovative strategy at their core, three specific aims directed at the fundamental operational principles of a multilayered neural network will be addressed: 1) The codes employed to represent odor information at each of the four olfactory processing stages, and the mapping rules that relate these codes, will be characterized. 2) The computational origin, physical form, and semantic content of neural symbols that express abstractions, classifications, and behavioral connotations will be elucidated in experiments that combine optical imaging with behavioral assays. The focus of these experiments will be on the neuronal substrate for attaching hedonic valence (i.e., attractiveness or repulsiveness) to odors, and on its modification by experience. 3) Mutations with defined neural or behavioral phenotypes, or artificial neural signals that will be inserted into genetically designated target neurons by selective photostimulation, will be used to perturb neuronal physiology; the impact of these perturbations at the systems level will be analyzed by optical imaging. This opens an opportunity to understand collective network properties in cellular or even molecular terms, and to transcend thereby some of the boundaries that currently divide neuroscience into mo ecu ar, ce u ar, and systems branches.