Neural Ensemble Codes in Drosophila Olfaction

超出提供的空间。新的实验技术被开发出来，通过光来监测和操纵体内遗传受限的神经元群体。这些技术将被用于研究果蝇黑腹果蝇嗅觉系统的信息处理。细胞型特异性启动子将靶向四个突触耦合处理层中的神经元：1)嗅觉感受器神经元，位于感觉表面并投射到触角叶，类似脊椎动物的嗅球；2)触角叶的局部抑制中间神经元；3)投射神经元，将嗅觉信息从触角叶传递到蘑菇体，即脊椎动物嗅皮层的类似物；以及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在每个基因突出的处理阶段通过光学显微镜可视化。以这一创新策略为核心，将针对多层神经网络的基本工作原理提出三个具体目标：1)通过比较不同气味的神经表征来表征四个嗅觉处理阶段的编码格式。2)与这些编码相关的映射规则将通过跟踪不同阶段的气味表征来阐明。3)在光学成像和行为分析相结合的实验中，研究表达抽象、分类和行为内涵的神经符号的计算起源、物理形式和语义内容。这些实验的重点将放在将享乐价与气味联系在一起的神经元底物上，以及经验对其进行修改。并行光学读出和极易处理的实验系统的结合为理解细胞甚至分子方面的集体网络属性提供了机会，从而超越了目前将神经科学划分为分子、细胞和系统分支的一些界限。这种统一的理解将为神经或精神疾病的发病机制提供信息，并揭示旨在改变网络功能的干预措施的潜在分子靶点。表演网站========================================Section End===========================================

EXCEED THE SPACE PROVIDED. 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 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 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. 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 coding formats at each of the four olfactory processing stages will be characterized by comparing the neural representations of different odors. 2) The mapping rules that relate these codes will be elucidated by tracing odor representations across stages. 3) The computational origin, physical form, and semantic content of neural symbols that express abstractions, classifications, and behavioral connotations will be studied in experiments that combine optical imaging with behavioral assays. The focus of these experiments will be on the neuronal substrate for attaching hedonic valence to odors, and on its modification by experience. The combination of a parallel optical read-out and an eminently tractable experimental system 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 molecular, cellular, and systems branches. Such a unified understanding will inform pathogenetic mechanisms in neurological or psychiatric disorders and disclose potential molecular targets for interventions aimed at altering network function. PERFORMANCE SITE ========================================Section End===========================================