The Journal of Neuroscience, December 3, 2008, 28(49):13075-13087; doi:10.1523/JNEUROSCI.2973-08.2008
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Behavioral/Systems/Cognitive
Olfactory Information Processing in the Drosophila Antennal Lobe: Anything Goes?
Ana F. Silbering,1,2
Ryuichi Okada,3
Kei Ito,3 and
C. Giovanni Galizia2
1Institute for Neurobiology, Free University of Berlin, D-14195 Berlin, Germany, 2Department of Biology, University of Konstanz, D-78457 Konstanz, Germany, and 3Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
Correspondence should be addressed to Prof. C. Giovanni Galizia, Lehrstuhl für Neurobiologie, Universität Konstanz, D-78457 Konstanz, Germany. Email: galizia{at}uni-konstanz.de
When an animal smells an odor, olfactory sensory neurons generate an activity pattern across olfactory glomeruli of the first sensory neuropil, the insect antennal lobe or the vertebrate olfactory bulb. Here, several networks of local neurons interact with sensory neurons and with output neurons—insect projection neurons, or vertebrate mitral/tufted cells. The extent and form of information processing taking place in these local networks has been subject of controversy. To investigate the role of local neurons in odor information processing we have used the calcium sensor G-CaMP to perform in vivo recordings of odor-evoked spatiotemporal activity patterns in five genetically defined neuron populations of the antennal lobe of Drosophila melanogaster: three distinct populations of local neurons (two GABAergic and one cholinergic), as well as sensory neurons and projection neurons. Odor-specific and concentration dependent spatiotemporal response patterns varied among neuron populations. Activity transfer differed along the olfactory pathway for different glomerulus–odor combinations: we found cases of profile broadening and of linear and complex transfer. Moreover, the discriminability between the odors also varied across neuron populations and was maximal in projection neurons. Discriminatory power increased with higher odor concentrations over a wide dynamic range, but decreased at the highest concentration. These results show the complexity and diversity of odor information processing mechanisms across olfactory glomeruli in the fly antennal lobe.
Key words: olfactory processing; odor concentration; antennal lobe network; local neurons; Drosophila melanogaster; calcium imaging
Received June 18, 2008;
revised Sept. 23, 2008;
accepted Oct. 11, 2008.
Correspondence should be addressed to Prof. C. Giovanni Galizia, Lehrstuhl für Neurobiologie, Universität Konstanz, D-78457 Konstanz, Germany. Email: galizia{at}uni-konstanz.de
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P. C. Fernandez, F. F. Locatelli, N. Person-Rennell, G. Deleo, and B. H. Smith
Associative Conditioning Tunes Transient Dynamics of Early Olfactory Processing
J. Neurosci.,
August 19, 2009;
29(33):
10191 - 10202.
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