Characterization and anatomical localization in the adult brain of protection from habituation to olfactory and mechanosensory stimuli. E. Skoulakis^1,2, S. Acevedo², K. Tsigkari¹. 1) Inst. Molecular Biology & Genetics, BSRC Alexander Fleming, Vari, GREECE; 2) Program in Genetics, Department of Biology, Texas A&M University, College Station TX USA.

   Diminished responses to repetitive stimuli defined as habituation constitute not only a type of non-associative learning but can serve as a filtering out mechanism for environmental cues with little predictive value and importance. However, fast habituation to salient but repetitive stimuli such as those utilized for olfactory conditioning in Drosophila is likely to negatively interfere with associative learning. We demonstrate that although wild type animals are protected from habituation to repetitive olfactory and mechanosensory stimuli for a finite period, they do diminish their responses with properties characteristic of habituation. Therefore, mechanisms protecting from quickly habituating to repetitive stimuli appear to operate in normal animals. Brain structural mutants, ablations and abrogation of neurotransmission methods were used to investigate the brain areas involved in protection from habituation. Consistent with the hypothesis that protection from habituation is an active process essential for normal brain function, the molecular mechanisms essential for protection from habituation appear compromised in D14-3-3 mutants, which habituate much faster than controls. These analyses provide a starting point for systematic molecular understanding not only of the mechanisms protecting from quick habituation, but of this type of non-associative learning as well.