rut^MB769 mutant flies show similar response profiles to wild-type flies in response to ethanol: flies have an initial startle response, a brief moment of quiescence followed by a sustained period of hyperactivity, and a reduction in locomotor speed leading to eventual immobility. However, the mutant flies have a significantly stronger startle response, show more movement during the brief period of quiescence, and have a less active and shorter sustained period of hyperactivity, leading to the faster onset of immobility. The increased startle of the mutants is composed of increased fast locomotion, increased bout length and a small increase in bout frequency. The activity bout length and bout frequency remains relatively constant throughout exposure of the mutants to ethanol but the degree of fast locomotion increases during the hyperactive phase and decreases during the sedation phase.

Hemizygous males show increased sensitivity to ethanol in an inebriometer assay.

Mild defect in initial learning and in 60 minute memory retention, measured in negatively reinforced olfactory discrimination paradigm.