Choice behavior of Drosophila facing contradictory visual cues

We studied the underlying neural mechanism of a simple choice behavior between competing alternatives in Drosophila. In a flight simulator, individual flies were conditioned to choose one of two flight paths in response to color and shape cues; after the training, they were tested with contradictory cues. Wild-type flies made a discrete choice that switched from one alternative to the other as the relative salience of color and shape cues gradually changed, but this ability was greatly diminished in mutant ([mbm.sup.1]) flies with miniature mushroom bodies or with hydroxyurea ablation of mushroom bodies. Thus, Drosophila genetics may be useful for elucidating the neural basis of choice behavior.
Most animals can make a rapid and rational choice among alternative behaviors by assessing the advantages and disadvantages on the basis of previous experience, but the underlying neural mechanism is [...]