Skip to main content
  • Poster presentation
  • Open access
  • Published:

Granule cell excitability mediates gamma and beta oscillations in a model of the dendrodendritic microcircuit

Odors evoke gamma (60 - 100 Hz) and beta (20 - 30 Hz) oscillations in the local field potential (LFP) of the rat olfactory bulb (OB). These oscillations arise from activity in the dendrodendritic microcircuit between excitatory mitral cells (MCs) and inhibitory granule cells (GCs) [1]. When cortical feedback inputs to the OB are blocked, beta oscillations are extinguished while gamma oscillations persist [2]. Much of this cortical feedback targets inhibitory interneurons in the GC layer and regulates the excitability of GCs [3], which suggests a causal link between the emergence of beta oscillations and the GC excitability. We investigate the effect that GC excitability has on network oscillations in a biophysical model of the MC-GC dendrodendritic network with graded inhibition. When GC excitability is low, there is transient activation of NMDAR channels by AMPARs, which produces fast inhibitory pulses in the gamma frequency range. When GC excitability is increased, the activation of NMDARs and other VDCCs is prolonged, allowing the slow decay time constants of these channels to drive beta frequency oscillations. The power of the beta oscillation peaks when inhibitory and excitatory currents onto MCs are balanced, which could explain the relationship between beta power and odor volatility measured experimentally [4].


  1. Lagier S, Carleton A, Lledo P-M: Interplay between local GABAergic interneurons and relay neurons generates gamma oscillations in the rat olfactory bulb. J. Neuroscience. 2004, 24: 4382-92.

    Article  PubMed  CAS  Google Scholar 

  2. Pressler RT, Inoue T, Strowbridge BW: Muscarinic receptor activation modulates granule cell excitability and potentiates inhibition onto mitral cells in the rat olfactory bulb. J. Neuroscience. 2007, 27: 10969-81.

    Article  PubMed  CAS  Google Scholar 

  3. Neville KR, Haberly LB: Beta and gamma oscillations in the olfactory system of the urethane-anesthetized rat. J. Neurophysiology. 2003, 90: 3921-30.

    Article  PubMed  Google Scholar 

  4. Lowry CA, Kay LM: Chemical factors determine olfactory system beta oscillations in waking rats. Journal of neurophysiology. 2007, 98: 394-404.

    Article  PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Boleslaw L Osinski.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Osinski, B.L., Kay, L.M. Granule cell excitability mediates gamma and beta oscillations in a model of the dendrodendritic microcircuit. BMC Neurosci 16 (Suppl 1), P118 (2015).

Download citation

  • Published:

  • DOI: