Research Description: Our lab is focusing on two related neurobiology questions:
Mammals can detect and discriminate infinite number of odorant chemicals. Over the last decade, dramatic progresses have been achieved in our understanding of the olfactory system. The work by Buck and Axel revealed that mammals possess over 1000 odorant receptors. Each olfactory sensory neuron expresses a single odorant receptor, and neurons of common receptors converge into one or two glomeruli in the the olfactory bulb, thus forming a topographic map at the level of odorant receptor. However, it remains unclear how odorants are encoded by the olfactory bulb. Our laboratory studies how neuronal activity in the olfactory bulb encode olfactory signals and then project to downstream stations, using approaches such as electrophysiology, optical imaging, and genetic engineering. Some special odorants, such as the body odorants emanated by other conspecifics or predators, can be detected at especially low concentrations and effectively release specific behaviors, such as mating, aggression, or innate fears. A discrete neural pathway from the olfactory bulb to the hypothalamus via the medial amygdala detects these odorants and regulates the innate social behaviors. We are using approaches including electrophysiology, neural tract tracing, genetic engineering, and behavioral assay to study the representation of the olfactory signals in this pathway. We are testing the labeled-line hypothesis: whether some specialized receptor neurons and their directly connected central pathways respond selectively to subset of social signals and regulate specific behavior. We are also recording the intrinsic and synaptic properties of the neurons in this pathway from slice preparations to examine the physiological substrates for the representation of social signals. Many mental diseases manifest themselves as disorders of social behavior. Our studies thus not only have the potentials of contributing to the basic understanding of sensory processing and some most fundamental forms of social behaviors but also may facilitate clinical efforts toward the cure of these diseases.
研究概述: 本实验室目前主要研究两个相关的神经生物学问题:
哺乳动物能够检测和区分不可胜数的气味分子。在过去的十多年中,嗅觉系统的研究有了突飞猛进的进步。Buck & Axel的工作揭示,在哺乳动物中有1000多种气味受体蛋白,每个受体细胞只表达一种受体。表达同一受体的细胞聚合到嗅球中的特定点,形成独特的空间组织方式。然而,对于气味分子在嗅球中的编码方式仍不清楚。我们实验室运用电生理,光学成像,及遗传工程的手段,研究嗅球内细胞对气味的表征及至下级中枢的投射。 一些特殊气味,类如其它同类或其天敌所释放的体味,能够尤其敏感地被检测并有效触发特定的行为,类如交配、攻击、或先天性的恐惧。这些信号的检测及对行为的影响主要通过由嗅球经内侧杏仁核至下丘脑的神经通路所完成。我们运用电生理、神经示踪、遗传工程及行为分析的手段,研究嗅觉信号在嗅球,内侧杏仁核及下丘脑的加工和表征。我们正在验证标记通路的假说:即是否有特定的受体细胞及与其直接相联的中枢通路通过选择性地对不同的社会性嗅觉信号起反应来调控相关的特定行为。我们也通过在脑切片条件下记录这些神经通路中细胞的内在特性及突触特性,来研究社会信号表征的生理基础。许多精神性疾病表现为社会行为的紊乱,因此我们的工作不仅可以有助于理解感觉系统和最基本的社会行为的神经生物学基础,亦可具有临床意义。
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