Olfactory Coding in the Drosophila Brain

描述（由申请人提供）：我们的长期目标是了解中枢神经系统中的嗅觉编码。在这个提议中，我们将调查果蝇蘑菇体中的刻板气味表征，并测试研究的空间活动模式编码气味信息的假设。果蝇和哺乳动物早期嗅觉系统的结构和功能逻辑非常相似。该系统的一个突出特征是肾小球中分离的受体活性的地形图。然而，这种空间活动模式如何转化为更高的中心，然后转化为气味感知仍然是一个谜。利用相对简单的神经系统和我们新开发的成像方法，我们已经能够揭示气味诱发的定型活动模式在一个更高的中心，蘑菇体。本研究拟通过活体果蝇的钙离子成像来监测气味诱导的蘑菇体细胞体和树突区域的神经元活动。在该制备中，通过常规显微镜获得活动空间模式的全局视图，而通过双光子激光显微镜分析单个神经元中的活动。我们将研究这种刻板的气味表示的基本属性，包括如何单一的气味，混合气味，气味的浓度表示在空间活动模式。然后，我们将通过比较图像分析和行为测试的结果来检验空间活动模式在气味辨别中的生理意义。最后，我们将使用遗传操作来帮助剖析气味信息是如何组织在蘑菇体的空间活动模式。

DESCRIPTION (provided by applicant): Our long-term goal is to understand olfactory coding in the central nervous system. In this proposal, we will investigate stereotyped odor representation in Drosophila mushroom body and test the hypothesis that spatial patterns of activity examined encode odor information. The organization and functional logic of early olfactory system appears remarkably similar in Drosophila and mammals. An outstanding feature of this system is the topographic map of receptor activity segregated in glomeruli. Yet, how such spatial patterns of activity are transformed to higher centers and then translated into odor perception remains illusive. Taking advantage of a relatively simple nervous system and our newly developed imaging method, we have been able to reveal odor-evoked stereotyped activity patterns in one of the higher centers, mushroom body. In this proposal, odor-induced neuronal activity in the regions of cell bodies and dendrites of mushroom body will be monitored via Ca 2+ imaging from living flies. In this preparation, a global view of spatial patterns of activity is obtained by conventional microscope while activity in individual neurons is analyzed by 2-photon laser microscope. We will investigate the basic properties of this stereotyped odor representation, including how single odorants, mixed odorants, and concentrations of odorants are represented in spatial patterns of activity. Then, we will examine physiological significance of spatial patterns of activity in odor discrimination by comparing results of imaging analysis with behavioral tests. Finally, we will use genetic manipulation to help to dissect how odor information is organized in spatial patterns of activity in mushroom body.