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

A combined computational-experimental study of dynamic responses to olfactory input in a glomerular circuit

Odorant-evoked input to and output from the mammalian olfactory bulb (OB) is temporally dynamic. Olfactory receptor neuron (ORN) inputs are tightly coupled to the respiratory cycle, and inhalation-evoked input bursts occur with durations, rise times, latencies, and strengths (amplitudes) that vary across glomeruli (for the same odorant) and also in individual glomeruli for different odorants [1]. The temporal spread of sensory input following a single inhalation (~100-300 ms) is comparable to the range of discrimination times for different olfactory tasks [2, 3], consistent with these dynamics being important in shaping odor perception. Similarly diverse temporal patterns of activity occur at the level of output from the OB, among mitral cells (MCs), whose firing patterns express strong temporal structure organized around the respiratory cycle and modulated by odorant presentation; significant odor information is carried in these temporal patterns across the MC population.

We investigate these temporal dynamics using a computational model of the ORN-MC circuit that uses a single-compartment, Hodgkin-Huxley-style MC model [4]. The input to the model MC is taken from recordings of odorant-evoked calcium influx into the presynaptic terminals of ORNs of awake, head-fixed rats engaged in an olfactory discrimination task [1, 5]. This calcium signal is converted to an excitatory synaptic input for the model MC having a temporal signature that presumably closely reproduces that of the signal received by real MCs. The response dynamics of the MC model are strongly shaped by the input signal (Figure 1). We explore how these dynamics vary for different odorants, synaptic strengths, and intrinsic MC parameters. We also investigate the response of a variant circuit that incorporates a mediating external tufted cell model between the ORN and MC [6].

Figure 1
figure 1

Sniffing and odor-evoked ORN input (top) imaged from an awake rat; ORN input is used to drive a model MC (bottom). Each sniff-evoked burst of ORN input elicits a burst of action potentials in the model MC.

References

  1. Carey RM, Verhagen JV, Wesson DW, Wachowiak M: Temporal Structure of Receptor Neuron Input to the Olfactory Bulb Imaged in Behaving Rats. J. Neurophysiol. 2009, 101: 1073-1088. 10.1152/jn.90902.2008.

    Article  PubMed Central  PubMed  Google Scholar 

  2. Abraham NM, Spors H, Carleton A, Margrie TW, Kuner T, Schaefer AT: Maintaining accuracy at the expense of speed: stimulus similarity defines odor discrimination time in mice. Neuron. 2004, 44: 865-876.

    CAS  PubMed  Google Scholar 

  3. Wesson DW, Donahou TN, Johnson MO, Wachowiak M: Sniffing behavior of mice during performance in odor-guided tasks. Chemical Senses. 2008, 33: 581-596. 10.1093/chemse/bjn029.

    Article  PubMed Central  PubMed  Google Scholar 

  4. Bathellier B, Lagier S, Faure P, Lledo PM: Circuit properties generating gamma oscillations in a network model of the olfactory bulb. J Neurophysiol. 2006, 95: 2678-2691. 10.1152/jn.01141.2005.

    Article  PubMed  Google Scholar 

  5. Verhagen JV, Wesson DW, Netoff TI, White JA, Wachowiak M: Sniffing controls an adaptive filter of sensory input to the olfactory bulb. Nat Neurosci. 2007, 10: 631-639. 10.1038/nn1892.

    Article  CAS  PubMed  Google Scholar 

  6. De Saint Jan D, Hirnet D, Westbrook GL, Chupak S: External Tufted Cells Drive the Output of Olfactory Bulb Glomeruli. J. Neurosci. 2009, 29 (7): 2043-2052. 10.1523/JNEUROSCI.5317-08.2009.

    Article  CAS  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Ryan Carey.

Rights and permissions

Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Carey, R., Sherwood, W.E. & Wachowiak, M. A combined computational-experimental study of dynamic responses to olfactory input in a glomerular circuit. BMC Neurosci 11 (Suppl 1), P129 (2010). https://0-doi-org.brum.beds.ac.uk/10.1186/1471-2202-11-S1-P129

Download citation

  • Published:

  • DOI: https://0-doi-org.brum.beds.ac.uk/10.1186/1471-2202-11-S1-P129

Keywords