Olfaction and olfactory learning in Drosophila: recent progress.

The olfactory system of Drosophila resembles that of vertebrates in its overall anatomical organization, but is considerably reduced in terms of cell number, making it an ideal model system to investigate odor processing in a brain [Vosshall LB, Stocker RF: Molecular architecture of smell and taste in Drosophila. Annu Rev Neurosci 2007, 30:505-533]. Recent studies have greatly increased our knowledge about odor representation at different levels of integration, from olfactory receptors to 'higher brain centers'. In addition, Drosophila represents a favourite model system to study the neuronal basis of olfactory learning and memory, and considerable progress during the last years has been made in localizing the structures mediating olfactory learning and memory [Davis RL: Olfactory memory formation in Drosophila: from molecular to systems neuroscience. Annu Rev Neurosci 2005, 28:275-302; Gerber B, Tanimoto H, Heisenberg M: An engram found? Evaluating the evidence from fruit flies. Curr Opin Neurobiol 2004, 14:737-744; Keene AC, Waddell S: Drosophila olfactory memory: single genes to complex neural circuits. Nat Rev Neurosci 2007, 8:341-354]. This review summarizes recent progress in analyzing olfactory processing and olfactory learning in Drosophila.