Natural Computation: Decision-Making Facing Conflicting Visual Cues and Crossmodal Interaction Between Olfactoryand Visual Learning in Drosophila

A prerequisite for any animal's survival is the ability to make decision about its sensory world. Here we show that (1) Drosophila can make discrete and firm choices among behavioural alternatives on the basis of small difference in the saliency of visual cues( color/shape and color/position dilemma); (2) Mushroom bodies in Drosophila brain are likely site for such choice behavior; (3) Dopamine neurons in Drosophila play a key role in the coding of negative reward (or punishment) probability and uncertainty behavior. Information received by the nervous system through multiple sensory modalities must be processed in an integrated manner. Different modalities of sensation interact in a synergistic or antagonistic manner during sensory perception, but whether there is also interaction during memory acquisition is largely unknown. in Drosophila reinforcement learning, we found that conditioning with concurrent visual and olfactory cues facilitated memory acquisition near the threshold level that was ineffective for unimodal conditioning and that this bimodal conditioning reduced the threshold for unimodal memory retrieval. Furthermore, bimodal preconditioning followed by unimodal conditioning with either visual or olfactory cue led to crossmodel memory transfer. Thus crossmodal memory acquisition exists in Drosophila and interactions between sensory modalities may play an important role for learning in a natural environment.