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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Neuroanat. | doi: 10.3389/fnana.2018.00115

Centrifugal inputs to the main olfactory bulb revealed through whole brain circuit-mapping

  • 1Medical Center, University of Rochester, United States
  • 2University of Rochester, United States
  • 3Nagoya University, Japan
  • 4Salk Institute for Biological Studies, United States

Neuronal activity in sensory regions can be modulated by attention, behavioral state, motor output, learning and memory. This is often done through direct feedback or centrifugal projections originating from higher processing areas. Though functionally important, the identity and organization of these feedback connections remain poorly characterized. Using a retrograde monosynaptic g-deleted rabies virus and whole-brain reconstructions, we identified the organization of feedback projecting neurons to the main olfactory bulb of the mouse. In addition to previously described projections from regions such as the Anterior Olfactory Nucleus (AON) and the piriform cortex, we characterized direct projections from pyramidal cells in the ventral CA1 region of hippocampus and the entorhinal cortex to the granule cell layer (GCL) of the main olfactory bulb (MOB). These data suggest that areas involved in stress, anxiety, learning and memory are all tethered to olfactory coding, two synapses away from where chemical compounds are first detected. Consequently, understanding olfactory perception, even at the earliest stages, may require studying memory and behavior as much as it does studying the physiochemical features of odors.

Keywords: Olfactory Bulb, Feedback, Olfaction, retrograde tracer, circuits

Received: 21 Aug 2018; Accepted: 04 Dec 2018.

Edited by:

Ricardo Insausti, University of Castilla La Mancha, Spain

Reviewed by:

Hirac Gurden, INSERM U1133 Physiologie de l'Axe Gonadotrope (Unité de biologie fonctionnelle et adaptative), France
Jorge A. Larriva-Sahd, National Autonomous University of Mexico, Mexico  

Copyright: © 2018 Padmanabhan, Osakada, Tarabrina, Kisser, Callaway, Gage and Sejnowski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: PhD. Krishnan Padmanabhan, Medical Center, University of Rochester, Rochester, United States,