Special Issue Review
Olfactory coding in the insect brain: data and conjectures
Version of Record online: 3 APR 2014
© 2014 The Author. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
European Journal of Neuroscience
Special Issue: EDITORS' ISSUE 2014
Volume 39, Issue 11, pages 1784–1795, June 2014
How to Cite
Galizia, C. G. (2014), Olfactory coding in the insect brain: data and conjectures. European Journal of Neuroscience, 39: 1784–1795. doi: 10.1111/ejn.12558
- Issue online: 1 JUN 2014
- Version of Record online: 3 APR 2014
- Manuscript Accepted: 13 FEB 2014
- Manuscript Revised: 11 FEB 2014
- Manuscript Received: 16 DEC 2013
- antennal lobe;
- mushroom bodies;
- neural networks;
- sensory coding
Much progress has been made recently in understanding how olfactory coding works in insect brains. Here, I propose a wiring diagram for the major steps from the first processing network (the antennal lobe) to behavioral readout. I argue that the sequence of lateral inhibition in the antennal lobe, non-linear synapses, threshold-regulating gated spring network, selective lateral inhibitory networks across glomeruli, and feedforward inhibition to the lateral protocerebrum cover most of the experimental results from different research groups and model species. I propose that the main difference between mushroom bodies and the lateral protocerebrum is not about learned vs. innate behavior. Rather, mushroom bodies perform odor identification, whereas the lateral protocerebrum performs odor evaluation (both learned and innate). I discuss the concepts of labeled line and combinatorial coding and postulate that, under restrictive experimental conditions, these networks lead to an apparent existence of ‘labeled line’ coding for special odors. Modulatory networks are proposed as switches between different evaluating systems in the lateral protocerebrum. A review of experimental data and theoretical conjectures both contribute to this synthesis, creating new hypotheses for future research.