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A model of the olfactory bulb and beyond


Li, Zhaoping (1990) A model of the olfactory bulb and beyond. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1Q5F-X469.


The olfactory bulb of mammals aids in the discrimination of odors. A mathematical model based on the bulbar anatomy and electrophysiology is described. Simulations of the highly non-linear model produce a 35-60 Hz modulated activity, which is coherent across the bulb. The decision states (for the odor information) in this system can be thought of as stable cycles, rather than as point stable states typical of simpler neuro-computing models. Analysis shows that a group of coupled non-linear oscillators are responsible for the oscillatory activities. The output oscillation pattern of the bulb is determined by the odor input. The model provides a framework in which to understand the transformation between odor input and bulbar output to the olfactory cortex. This model can also be extended to other brain areas such as the hippocampus, thalamus, and neocortex, which show oscillatory neural activities. There is significant correspondence between the model behavior and observed electrophysiology.

It has also been suggested that the olfactory bulb, the first processing center after the sensory cells in the olfactory pathway, plays a role in olfactory adaptation, odor sensitivity enhancement by motivation, and other olfactory psychophysical phenomena. The input from the higher olfactory centers to the inhibitory cells in the bulb are shown to be able to modulate the response, and thus the sensitivity, of the bulb to odor input. It follows that the bulb can decrease its sensitivity to a pre-existing and detected odor (adaptation) while remaining sensitive to new odors, or can increase its sensitivity to discover interesting new odors. Other olfactory psychophysical phenomena such as cross-adaptation are also discussed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:olfaction, model, neurons, odor classification, adaptation
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hopfield, John J.
Thesis Committee:
  • Thorne, Kip S. (chair)
  • Cross, Michael Clifford
Defense Date:18 September 1989
Non-Caltech Author (AT)
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-87-K-0377
Record Number:CaltechTHESIS:02192014-080819270
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8083
Deposited By: Benjamin Perez
Deposited On:19 Feb 2014 16:47
Last Modified:09 Nov 2022 19:20

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