Beschreibung:
<jats:p>Insect and mammalian olfactory systems are strikingly similar. Therefore,
<jats:italic>Drosophila</jats:italic> can be used as a simple model for olfaction and olfactory
learning. The brain of adult <jats:italic>Drosophila</jats:italic>, however, is still complex.
We therefore chose to work on the larva with its yet simpler but adult-like
olfactory system and provide evidence for olfactory learning in individually
assayed <jats:italic>Drosophila</jats:italic> larvae. We developed a differential conditioning
paradigm in which odorants are paired with positive (“+” fructose)
or negative (“-” quinine or sodium chloride) gustatory
reinforcers. Test performance of individuals from two treatment conditions is
compared—one received odorant A with the positive reinforcer and odorant
B with a negative reinforcer (A+/B-); animals from the other treatment
condition were trained reciprocally (A-/B+). During test, differences in
choice between A and B of individuals having undergone either A+/B- or A-/B+
training therefore indicate associative learning. We provide such evidence for
both combinations of reinforcers; this was replicable across repetitions,
laboratories, and experimenters. We further show that breaks improve
performance, in accord with basic principles of associative learning. The
present individual assay will facilitate electrophysiological studies, which
necessarily use individuals. As such approaches are established for the larval
neuromuscular synapse, but not in adults, an individual larval learning
paradigm will serve to link behavioral levels of analysis to synaptic
physiology.</jats:p>