Investigating axonal and glial adaptations to sensory manipulations in the olfactory system

项目摘要 在嗅球中，二尖瓣和簇状细胞的放电率和协调放电模式编码 嗅觉信息方面，包括气味身份和气味是否值得注意（气味显著性）。 在整个生命过程中，这些放电特性会随着动物的学习而发生巨大变化。当当地电路 和离心输入调节二尖瓣和簇状细胞的输出是合理的理解， 事实上，我们对这些细胞如何将气味信息传递到其他感觉处理区域的理解还很有限。 沿着长的有髓鞘的轴突束。轴突结构域如轴突起始段和有髓鞘的 像兰维尔结和髓鞘这样的区域在神经元放电特性中起重要作用， 传导速度，但他们是否适应促进成人的信息处理尚不清楚。这 一项提案包括两个目标，旨在检验轴突结构域在响应中发生变化的假设 与成年动物的神经元活动有关。第一个目标是使用免疫组织化学和电子显微镜， 研究成年动物的轴突起始段、髓鞘和朗维尔节的结构 在单侧鼻孔阻塞的感觉剥夺后， 联想学习模式，小鼠学习检测和气味。我将决定是否改编 发生在感觉剥夺和学习之后。第二个目的是调查生理后果 感觉剥夺和学习嗅球外轴突的功能。在一起， 这些实验试图验证髓鞘和轴突区域适应感觉操纵的假设。 在成年人中参与嗅觉感觉处理。

PROJECT SUMMARY In the olfactory bulb, the firing rates and coordinated firing patterns of mitral and tufted cells encode aspects of olfactory information including odor identity and whether an odor deserves attention (odor salience). Throughout life, these firing properties can change dramatically as an animal learns. While the local circuits and centrifugal inputs modulating the output of mitral and tufted cells are reasonably well understood, there is virtually no understanding of how these cells transmit odor information to other sensory processing regions along long, myelinated axonal tracts. Axonal domains such as the axon initial segment and myelinated domains like nodes of Ranvier and the myelin sheath play a vital role in neuronal firing properties and conduction velocity, but whether they adapt to facilitate information processing in adults is not known. This proposal is comprised of two aims which seek to test the hypothesis that axonal domains change in response to neuronal activity in adult animals. The first aim uses immunohistochemistry and electron microscopy to investigate the structure of the axon initial segments, myelin sheaths, and nodes of Ranvier in adult animals following sensory deprivation with unilateral naris occlusion, and an optogenetic version of the go-no go associative learning paradigm where mice learn to detect and odorant. I will determine whether adaptations occur following sensory deprivation and learning. The second aim investigates the physiological consequences of sensory deprivation and learning on the function of axons projecting out of the olfactory bulb. Together, these experiments seek to test the hypothesis that myelin and axonal domains adapt to sensory manipulations in adults and participate in olfactory sensory processing.