Benjamin Fabian

   Research Group Olfactory Coding
 Phone:+49 (0)3641 57 1452Max Planck Institute for Chemical Ecology
 Fax:-Hans-Knöll-Straße 8
  emailD-07745 Jena

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The sense of olfaction is very crucial for insects in order to navigate in a complex environment of volatile odorants. Olfactory cues play a major role in locating suitable substrates for feeding and oviposition, and are necessary for finding potential mating partners or for the avoidance of predators and parasitoids. The structure and function of the olfactory system of Drosophila melanogaster is well understood and documented. However, little is known about whether and to which extent individual experience is able to transform certain parts of this system.
Odor molecules bind to specific olfactory receptors on the antennal and maxillary palp surface. From these receptors, information about the constitution of the chemical environment is passed to higher neuronal centers, namely the antennal lobe, the mushroom body and the lateral horn. The first modulation of this information takes place in the glomeruli of the antennal lobe. Each of them consists of odor-specific olfactory sensory neurons (OSNs), local interneurons (LNs) and projection neurons (PNs). Studies have shown that glomeruli increase in size when they are stimulated by the presence of their associated odor molecules for several days, and decrease in size again after a few days without the stimulus.
We try to find the cause that underlies this plasticity. For this, flies are cyclically exposed to geosmin, a strongly aversive odor molecule. The geosmin molecules bind to the Or56a receptor, which is expressed in OSNs that converge to the DA2 glomerulus in the antennal lobe. The glomerulus of treated flies is then analyzed to document the volume increase and number of OSNs and PNs. For the visualization of neurons, we express photoactivatable GFP in certain glomeruli in transgenic flies. To allow general conclusions for the experience-dependent plasticity of olfactory circuits, we aim for additional experiments with other odors to stimulate different sets of glomeruli.
last updated on 2017-08-03