A Mirror-Symmetric Excitatory Link Coordinates Odor Maps across Olfactory Bulbs and Enables Odor Perceptual Unity

Mark Grobman, Tal Dalal, Hagar Lavian, Ronit Shmuel, Katya Belelovsky, Fuqiang Xu, Alon Korngreen, Rafi Haddad

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Sensory input reaching the brain from bilateral and offset channels is nonetheless perceived as unified. This unity could be explained by simultaneous projections to both hemispheres, or inter-hemispheric information transfer between sensory cortical maps. Odor input, however, is not topographically organized, nor does it project bilaterally, making olfactory perceptual unity enigmatic. Here we report a circuit that interconnects mirror-symmetric isofunctional mitral/tufted cells between the mouse olfactory bulbs. Connected neurons respond to similar odors from ipsi- and contra-nostrils, whereas unconnected neurons do not respond to odors from the contralateral nostril. This connectivity is likely mediated through a one-to-one mapping from mitral/tufted neurons to the ipsilateral anterior olfactory nucleus pars externa, which activates the mirror-symmetric isofunctional mitral/tufted neurons glutamatergically. This circuit enables sharing of odor information across hemispheres in the absence of a cortical topographical organization, suggesting that olfactory glomerular maps are the equivalent of cortical sensory maps found in other senses. Grobman et al. report that isofunctional output neurons in the two olfactory bubs are interconnected and spatially mirror-symmetric. This circuit enables the sharing of odor information between hemispheres despite the lack of topographical organization of odor information in the cortex.

Original languageEnglish
Pages (from-to)800-813.e6
Issue number4
StatePublished - 22 Aug 2018

Bibliographical note

Publisher Copyright:
© 2018 Elsevier Inc.


We thank Dan Rokni and Yoram Ben-Shaul for fruitful discussions and helpful comments on the manuscript. This study was supported by the ISF-China grant 2545/16 , Chinese-Israel Grant from the NSFC ( 81661148053 ), and the Marie Curie FP7-PEOPLE-2013-CIG-631048.

FundersFunder number
Marie CurieFP7-PEOPLE-2013-CIG-631048
National Natural Science Foundation of China81661148053


    • AONpE
    • bilateral information transfer
    • inter-hemispheric
    • mirror-symmetric
    • odor
    • odor maps
    • olfaction
    • optogenetics
    • perceptual unity


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