Olfactory coding in a simple system: adaptation inDrosophilalarvae

Abstract

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 e¡ectively reduced to zero (abolished) test responses to all six alcohols, whereas test responses to hexanol were only a¡ected 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 e¡ect of pre-stimulation with butanol and pentanol, were not signi¢cantly di¡erent, 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 fruit£y maggot is presented that explains the data and provides predictions for future anatomical, genetic and electrophysiological studies.

Oriented responses of grapevine moth larvae Lobesia botrana to volatiles from host plants and an artificial diet on a locomotion compensator

“…1-Hexanol caused a dose dependent increase in attraction and was the compound that induced the highest target vector response values from Lobesia larvae. This attraction indicates that 1-hexanol plays a fundamental role in the olfactory responses of these larvae, as has also been found for Drosophila melanogaster larvae (Cobb and Domain, 2000;Oppliger et al, 2000). 1-Hexanol was also tested here in 1:1 (v/v) binary mixtures with host plant compounds of other chemical classes.…”

Input-Driven Components of Spike-Frequency Adaptation Can Be UnmaskedIn Vivo

“…The method that we apply to detect input-driven adaptation may be viewed as a variant of the cross-adaptation technique (McBurney et al, 1972;Cobb and Domain, 2000;Heinrich and Bach, 2002). This is frequently used to investigate whether the processing of different stimuli occurs along a common pathway; if adaptation to one stimulus carries over to another, a common pathway can be assumed.…”

Developmentally programmed remodeling of theDrosophilaolfactory circuit

“…The Drosophila larval olfactory system is much smaller and simpler by comparison (Cobb and Domain, 2000;Heimbeck et al, 1999), shown to consist of only 21 ORNs in the dorsal organ (Singh and Singh, 1984) and believed to include ~50 PNs relaying information to the larval MB and LH (Python and Stocker, 2002;Stocker, 1994). Developmental analysis has shown that the PNs born during larval stages exhibit only a single unbranched process from the cell body to the MB calyx until early metamorphosis, when dendrites and axon terminal branches start to elaborate (Jefferis et al, 2004).…”