Drosophila has been proven to be a powerful animal model to study genetic mechanisms underlying different behaviors and diseases (Sokolowski,2001;Bier,2005).Extinction is a process that repeated presentation of a conditioned stimulus without reinforcement results in decreased conditioned responses (Bouton,2004) and receives increasing attention for treating its related diseases such as post-traumatic stress disorder (PTSD) and addiction (Milad and Quirk,2012;Milton and Everitt,2012).Several studies have made significant progress in understanding extinction effect of punishment memory using Drosophila (Schwaerzel et al.,2002;Lagasse et al.,2009;Qin and Dubnau,2010;Hirano et al.,2016;Felsenberg et al.,2018),which provides important clues for PTSD treatment.In contrast,there are few studies about extinction effect of reward memory (Felsenberg et al.,2017),which may help treat addiction.Given that extinguished addiction memories recover easily and spontaneously with time,a key question in clinical treatment is how to extend the persistence of extinction effect of addiction memory (Milton and Everitt,2012).It is important to study genetic mechanisms underlying the persistence of reward memory extinction to address this key question.However,as an ideal model with powerful genetic tools,Drosophila lacks a suitable paradigm to study such a question.Here,we establish a new behavioral paradigm for studying genetic mechanisms in determining the persistence of reward memory extinction in Drosophila.