When facing competing visual cues,Drosophila chooses a flight path in a flight simulator based on the relative saliency of the cues.We found that this choice behavior consists of two phases:an early phase that required dopaminergic and mushroom bodies activities,and a late phase independent of these activities.Immunohistological analysis showed that mushroom bodies are densely innervated by the axons of doparninergic neurons.Thus the circuit from the dopamine system to mushroom bodies is crucial for choice behavior.