Network Mechanism for Insect Olfaction

TL;DR

This paper investigates the common dynamical behaviors in insect and mammalian olfactory pathways, proposing that specific network time scales and bifurcation structures underlie these similarities, supported by conductance-based and firing-rate models.

Contribution

The study introduces a simplified conductance-based integrate-and-fire model and a firing-rate model to explain the shared dynamical features of olfactory networks across species.

Findings

Fast excitation and inhibition time scales are key to similar olfactory responses.

A saddle-node-on-an-invariant-circle bifurcation structure underpins the dynamics.

The bifurcation structure may be present in other sensory systems.

Abstract

Early olfactory pathway responses to the presentation of an odor exhibit remarkably similar dynamical behavior across phyla from insects to mammals, and frequently involve transitions among quiescence, collective network oscillations, and asynchronous firing. We hypothesize that the time scales of fast excitation and fast and slow inhibition present in these networks may be the essential element underlying this similar behavior, and design an idealized, conductance-based integrate-and-fire (I&F) model to verify this hypothesis via numerical simulations. To better understand the mathematical structure underlying the common dynamical behavior across species, we derive a firing-rate (FR) model and use it to extract a slow passage through a saddle-node-on-an-invariant-circle (SNIC) bifurcation structure. We expect this bifurcation structure to provide new insights into the understanding of the dynamical behavior of neuronal assemblies and that a similar structure can be found in other sensory systems.