Olfactory Coding in the Drosophila Brain

描述(由申请者提供)：我们的长期目标是了解中枢神经系统中的嗅觉编码。在这项提议中，我们将研究果蝇蘑菇体中刻板印象的气味表征，并测试被检查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组织和功能逻辑似乎非常相似。该系统的一个显著特征是肾小球内分离的受体活性的地形图。然而，这种活动的空间模式是如何转化到更高的中心，然后转化为气味感知的，仍然是虚幻的。利用一个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引起的刻板印象的活动模式在较高的中枢之一，蘑菇体。在这项建议中，气味诱导的神经元活动在蘑菇体的细胞体和树突区域将通过活体苍蝇的钙成像进行监测。在这项准备中，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的活动。我们将研究这种刻板印象的气味表示的基本属性，包括如何在活动的空间模式中表示单一气味、混合气味和气味浓度。然后，我们将通过比较图像分析和行为测试的结果来检验气味识别中活动空间模式的生理意义。最后，我们将使用基因操作来帮助剖析气味信息是如何在蘑菇体内的活动空间模式中组织起来的。

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.