《美国科学院院刊》（PNAS）发表了中国科学院上海生命科学研究院神经科学研究所王佐仁研究组的最新研究成果─“Functional feedback from mushroom bodies to antennal lobes in the Drosophila olfactory pathway”。这项工作主要由博士后胡爱群和研究生张伟在王佐仁研究员的指导下共同完成。

        信息反馈在感觉处理中起着重要的作用。在昆虫中，蘑菇体结构被认为介导嗅觉的学习与记忆及多感觉的整合。Menzel实验室的钴标记研究提示：蜜蜂的蘑菇体与触角叶之间可能存在反馈环路。作者利用遗传学方法将外源P2X2受体特异表达在果蝇的蘑菇体从而研究果蝇的蘑菇体至触角叶的反馈。蘑菇体的激活以乙酰胆碱受体依赖的方式诱发了触角叶的投射神经元和局部中间神经元的去极化改变。蘑菇体神经元βγ-轴突的激活与胞体的激活相比，引起了更强的触角叶神经元的去极化改变。这些结果表明：果蝇蘑菇体与触角叶之间存在功能反馈，这种反馈很可能是经βγ-轴突介导的。果蝇蘑菇体至触角叶的功能性反馈提示果蝇嗅觉信息处理存在着自上而下的调节。

        该工作得到了科技部973项目、国家自然科学基金、中科院百人计划和知识创新项目的支持，以及中国博士后基金、上海博士后基金的资助。

原文出处：

PNAS  doi: 10.1073/pnas.0914912107

Functional feedback from mushroom bodies to antennal lobes in the Drosophila olfactory pathway
Aiqun Hua,1, Wei Zhanga,b,1, and Zuoren Wanga,2

Feedback plays important roles in sensory processing. Mushroom bodies are believed to be involved in olfactory learning/memory and multisensory integration in insects. Previous cobalt-labeling studies have suggested the existence of feedback from the mushroom bodies to the antennal lobes in the honey bee. In this study, the existence of functional feedback from Drosophila mushroom bodies to the antennal lobes was investigated through ectopic expression of the ATP receptor P2X2 in the Kenyon cells of mushroom bodies. Activation of Kenyon cells induced depolarization in projection neurons and local interneurons in the antennal lobes in a nicotinic receptor-dependent manner. Activation of Kenyon cell axons in the βγ-lobes in the mushroom body induced more potent responses in the antennal lobe neurons than activation of Kenyon cell somata. Our results indicate that functional feedback from Kenyon cells to projection neurons and local interneurons is present in Drosophila and is likely mediated by the βγ-lobes. The presence of this functional feedback from the mushroom bodies to the antennal lobes suggests top-down modulation of olfactory information processing in Drosophila