Transient forgetting of early formed memory in drosophila

Abstract

AbstractBackgroundForgetting is a natural biological process not only to remove the stored memory but also to offer flexibility for future behaviors. Based on the retrievability of forgotten memory, forgetting could be subcategorized into permeant forgetting and transient forgetting. Compared to permeant forgetting, the cellular mechanism of transient forgetting is largely unknown. Early‐formed memory is mostly unconsolidated and sensitive to interruption; therefore, it is unclear if transient forgetting could be induced during the early stage of memory formation, and if acquired information remains intact after external stimulation‐induced forgetting.MethodThe current study used Drosophila as a model system with genetic behavioral settings to investigate the cellular mechanism of transient forgetting of early‐formed memory.ResultWe found that transient forgetting only temporally blocks memory retrieval and learned information was preserved. The lost memory spontaneously recovered after 30‐40 minutes. Our results showed that dopamine plays an important role in meditating transient forgetting. We also demonstrated that transient forgetting is different from extinction as the underlying cellular mechanism is different and the induction protocol is not the same. External stimulation recruits dopaminergic neurons to modify the behavior output to temporally interrupt memory recall. Further study showed that the encoding remains functional during transient forgetting, suggesting animals' basal cognitive functions are largely unaffected.ConclusionAs transient forgetting is often observed during neurodegenerative diseases, the current study not only reveals the detailed cellular mechanism of transient forgetting of early‐formed memory but also how transient forgetting affects disease progression.