From the Olfactory Bulb to Higher Brain Centers: Genetic Visualization of Secondary Olfactory Pathways in Zebrafish
From the Olfactory Bulb to Higher Brain Centers: Genetic Visualization of Secondary Olfactory Pathways in Zebrafish
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DOI：
10.1523/jneurosci.0118-09.2009
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发表时间：
2009-04-15
影响因子：
5.3
通讯作者：
Yoshihara, Yoshihiro
中科院分区：
文献类型：
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作者：
Miyasaka, Nobuhiko;Morimoto, Kozo;Yoshihara, Yoshihiro
在脊椎动物的嗅觉系统中，气味信息被表示为嗅球(OB)中的地形图。然而，这种气味映射是如何从嗅觉中枢传递到高级嗅觉中枢的，目前还不清楚。利用斑马鱼的遗传标记技术，我们发现OB输出神经元，即二尖瓣细胞(MCs)，在转基因表达谱和空间分布方面是异质性的。在单细胞分辨率下追踪MC轴突发现：(1)单个MC将轴突发送到前脑的多个靶区；(2)支配同一肾小球的MC不一定表现出相同的轴突轨迹；(3)支配不同肾小球簇的MC倾向于将轴突投射到不同的但部分重叠的靶区；(4)支配内侧肾小球簇的MC直接不对称地将轴突发送到右侧缰核。我们认为OB的地形图并不是完好无损的，而是在高级嗅觉中枢重新组织起来的。此外，我们发现的非对称球-缰核投射使嗅觉系统成为研究大脑不对称和偏侧化行为的一个有吸引力的模型。
In the vertebrate olfactory system, odor information is represented as a topographic map in the olfactory bulb (OB). However, it remains unknown how this odor map is transferred from the OB to higher olfactory centers. Using genetic labeling techniques in zebrafish, we found that the OB output neurons, mitral cells (MCs), are heterogeneous with respect to transgene expression profiles and spatial distributions. Tracing MC axons at single-cell resolution revealed that (1) individual MCs send axons to multiple target regions in the forebrain; (2) MCs innervating the same glomerulus do not necessarily display the same axon trajectory; (3) MCs innervating distinct glomerular clusters tend to project axons to different, but partly overlapping, target regions; (4) MCs innervating the medial glomerular cluster directly and asymmetrically send axons to the right habenula. We propose that the topographic odor map in the OB is not maintained intact, but reorganized in higher olfactory centers. Moreover, our finding of asymmetric bulbo-habenular projection renders the olfactory system an attractive model for the studies of brain asymmetry and lateralized behaviors.