Genetic and Functional Dissection of Neuronal Circuits in Drosophila Visual Learning.

The two Drosophila larval eyes are composed of 12 photoreceptor neurons (PR) each. 8 PR express the green-sensitive Rhodopsin6 (Rh6) and 4 express the blue-sensitive Rhodopsin5 (Rh5). All PR project into the larval optic neuropile (LON), where light information is transmitted to higher order visual neurons. Drosophila larvae are able to associate positive or negative cues with light or darkness, thus changing their native light avoidance behavior (light as conditioned stimulus). It was shown that light can also be used as an unconditioned stimulus (punishment) notably in olfactory classical conditioning paradigm. This result suggests that two different kinds of visual memories are formed (von Essen et al. 2011). However the neural circuit involved in visual learning and memory formation remains largely unknown. To analyze the behavioral and neuronal basis of visual learning we decided to create a robust tracking setup to detect all larval behavioral changes at high resolution during the learning process and memory retrieval.