Distributed representation of chemical features and tunotopic organization of glomeruli in the mouse olfactory bulb
Distributed representation of chemical features and tunotopic organization of glomeruli in the mouse olfactory bulb
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DOI：
10.1073/pnas.1117491109
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发表时间：
2012-04-03
影响因子：
11.1
通讯作者：
Yu, C. Ron
中科院分区：
文献类型：
--
作者：
Ma, Limei;Qiu, Qiang;Yu, C. Ron
在哺乳动物的大脑中，感觉刺激的相似特征通常在感觉区域中邻近地表现出来。然而，化学特征如何在嗅球中表现一直存在争议。人们提出的问题是，气味分子的特定化学特征是否由空间聚集的嗅肾小球代表。使用敏感探针，我们分析了肾小球在单个肾小球分辨率下对大量气味剂的反应。与一般观点相反，我们发现化学特征的表征在嗅球中是空间分布的，没有可辨别的化学特征。此外，一般来说，气味诱发的活动模式与气味结构并不直接相关。尽管在化学特征方面缺乏空间聚类或偏好，但一些结构相关的气味可以类似地由空间分布的肾小球集合来表示，这就解释了它们的感知相似性。虽然肾小球没有化学组织，并且可以对来自多个类别的气味进行调节，但我们发现肾小球根据它们的气味调节相似性分层排列成簇。这种内源性排列为理解肾小球的空间组织提供了一个框架，它符合其他感觉系统的组织原则。
In the mammalian brain, similar features of the sensory stimuli are often represented in proximity in the sensory areas. However, how chemical features are represented in the olfactory bulb has been controversial. Questions have been raised as to whether specific chemical features of the odor molecules are represented by spatially clustered olfactory glomeruli. Using a sensitive probe, we have analyzed the glomerular response to large numbers of odorants at single glomerulus resolution. Contrary to the general view, we find that the representation of chemical features is spatially distributed in the olfactory bulb with no discernible chemotopy. Moreover, odor-evoked pattern of activity does not correlate directly with odor structure in general. Despite the lack of spatial clustering or preference with respect to chemical features, some structurally related odors can be similarly represented by ensembles of spatially distributed glomeruli, providing an explanation of their perceptual similarity. Whereas there is no chemotopic organization, and the glomeruli are tuned to odors from multiple classes, we find that the glomeruli are hierarchically arranged into clusters according to their odor-tuning similarity. This tunotopic arrangement provides a framework to understand the spatial organization of the glomeruli that conforms to the organizational principle found in other sensory systems.