Olfactory coding in a simple system: adaptation in Drosophila larvae.
Drosophila melanogaster larvae were pre-stimulated with high concentrations of six homologous alcohols (C4-C9) and then tested for adaptation and cross-adaptation using these same alcohols, four aliphatic n-acetates and three acids. Pre-stimulation with hexanol effectively reduced to zero (abolished) test responses to all six alcohols, whereas test responses to hexanol were only affected by pre-stimulation with hexanol. This substance appears to play a fundamental role in the organization of the larval olfactory system. Test responses to butanol and pentanol, and the effect of pre-stimulation with butanol and pentanol, were not significantly different, indicating that they are sensory equivalents. Heptanol, octanol and nonanol induce a complex set of responses among one another. Cross-adaptation between functional groups was observed, in particular following pre-stimulation with hexanol, but there was also evidence that functional groups are coded separately. A model of olfactory processing in the fruitfly maggot is presented that explains the data and provides predictions for future anatomical, genetic and electrophysiological studies.
Cobb
M
M
CNRS-UMR 7625, Bâtiment A 7e, 7 Quai St Bernard, 75005 Paris, France. mcobb@snv.jussieu.fr
Domain
I
I
D000085:Acetates; D000143:Acids; D000222:Adaptation, Physiological; D000438:Alcohols; D000818:Animals; D004331:Drosophila melanogaster / Q000502:physiology*; D007814:Larva / Q000502:physiology; D008954:Models, Biological; D018034:Olfactory Receptor Neurons / Q000502:physiology; D012903:Smell / Q000502:physiology*
D000085:Acetates; D000143:Acids; D000438:Alcohols