A model of the olfactory bulb and beyond

olfaction,model, neurons, odor classification, adaptation

Li, Zhaoping ; Hopfield, John J.

University:California Institute of Technology

Department:Physics, Mathematics and Astronomy

关键词: olfaction,model, neurons, odor classification, adaptation;   

Others  :  https://thesis.library.caltech.edu/8083/8/Li_z_1990.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

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

It has also been suggested that the olfactory bulb, the first processing center after thesensory cells in the olfactory pathway, plays a role in olfactory adaptation, odor sensitivityenhancement by motivation, and other olfactory psychophysical phenomena. The inputfrom the higher olfactory centers to the inhibitory cells in the bulb are shown to be ableto modulate the response, and thus the sensitivity, of the bulb to odor input. It followsthat 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 interestingnew odors. Other olfactory psychophysical phenomena such as cross-adaptation are alsodiscussed.