Neuron：大脑两侧嗅觉图谱连接机制研究

生物谷报道：北京生命科学研究所研究人员22日在《神经元》杂志发表了一篇关于嗅觉机制的文章。该文章报道了小鼠嗅球两侧对称的嗅觉图谱通过大脑中一个特化的嗅觉区域精确地连接起来，以及此连接在嗅觉信息传递中有重要作用。

感觉系统用在大脑两侧对称排列的精确感觉图谱来代表如图像、气味等生理刺激。但是，大脑两侧对称的感觉图谱是怎么连接的仍然不清楚。研究数据表明，一个很少研究的嗅觉皮层核团——前外侧嗅核(anterior olfactory nucleus pars externa)，精确地把位于嗅球两侧对称的嗅觉图谱连接起来。电生理和行为分析进一步表明前外侧嗅核对两侧嗅球的气味信息交换包括嗅觉记忆有必要的作用。

通过对割裂脑病人（两侧大脑被分开的病人）的研究，罗杰·斯佩里(Roger W. Sperry)等发现两侧大脑的连接对于认知与行为起着重要作用，并于1981年获得诺贝尔奖，但大脑两侧相互作用的机理至今仍然是一个谜团。本文发现两侧嗅球通过前外侧嗅核的精确连接，为进一步揭开两侧大脑相互作用的机理提供了一个可以基因操作的模型。该期《神经元》杂志专门为该文发表了一篇题为“Interhemispheric Olfactory Circuit and the Memory Beyond”的评述文章。（生物谷 www.bioon.com）

生物谷推荐原始出处：

Neuron，Vol 58, 613-624，Zhiqiang Yan，Minmin Luo

Precise Circuitry Links Bilaterally Symmetric Olfactory Maps

Zhiqiang Yan,¹,² Jie Tan,¹,² Chang Qin,² Yao Lu,² Cheng Ding,² and Minmin Luo²,

¹Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
²National Institute of Biological Sciences, Beijing, 102206, China

Corresponding author
Minmin Luo
luominmin@nibs.ac.cn

Olfactory sensory neurons expressing a common receptor gene converge onto one or a few glomeruli with stereotyped positions within the mouse main olfactory bulb (MOB), producing a map of ∼1800 olfactory columns representing ∼1000 odorant receptors. Here, we report that this precise olfactory map is maintained over several synapses that ultimately cross MOB hemispheres to link bilateral isofunctional olfactory columns. Focal injection of tracer into genetically identified glomeruli revealed an exquisite topography that involves a bilateral connection via the anterior olfactory nucleus pars externa (AONpE) that links isofunctional olfactory columns in the contralateral MOB. Physiological and behavioral assays revealed an important role for the AONpE in bilateral exchange of odorant-specific information. These results indicate that the interbulbar link through the AONpE integrates bilateral olfactory sensory maps and exchanges olfactory information, positioning it as a unique model system for studying interhemispheric connections.