Transient dynamics between displaced fixed points: an alternate nonlinear dynamical framework for olfaction

Buckley, Christopher L and Nowotny, Thomas (2012) Transient dynamics between displaced fixed points: an alternate nonlinear dynamical framework for olfaction. Brain Research, 1434. pp. 62-72. ISSN 0006-8993

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Abstract

Significant insights into the dynamics of neuronal populations have been gained in the olfactory system where rich spatio-temporal dynamics is observed during, and following, exposure to odours. It is now widely accepted that odour identity is represented in terms of stimulus-specific rate patterning observed in the cells of the antennal lobe (AL). Here we describe a nonlinear dynamical
framework inspired by recent experimental findings which provides a compelling account of both the origin and the function of these dynamics. We start by analytically reducing a biologically plausible conductance based model of the AL to a quantitatively equivalent rate model and construct conditions such that the rate dynamics are well described by a single globally stable fixed point (FP). We then describe the AL's response to an odour stimulus as rich transient trajectories between this stable baseline state (the single FP in absence of odour stimulation) and the odour-specific position of the single FP during odour stimulation.
We show how this framework can account for three phenomena that are observed experimentally. First, for an inhibitory period often observed immediately after an odour stimulus is removed. Second, for the qualitative differences between the dynamics in the presence and the absence of odour. Lastly, we show how it can account for the invariance of a representation of odour identity to both the duration and intensity of an odour stimulus. We compare and contrast this framework with the currently prevalent nonlinear dynamical framework of 'winnerless competition' which describes AL dynamics in terms of heteroclinic orbits

Item Type: Article
Schools and Departments: School of Engineering and Informatics > Informatics
Subjects: Q Science > Q Science (General)
R Medicine > RC Internal medicine > RC0321 Neurosciences. Biological psychiatry. Neuropsychiatry
Depositing User: Thomas Nowotny
Date Deposited: 20 Apr 2012 14:05
Last Modified: 07 Mar 2017 04:24
URI: http://sro.sussex.ac.uk/id/eprint/38435

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