A paradoxical impact of alcohol on sleep-memory coupling

Sleep serves a fundamental role in memory consolidation, and yet it must adapt to the organisms physiological state. Acute ethanol consumption has a profound impact on animal physiology, but whether intoxication affects the role of sleep in memory consolidation remains unexplored. We demonstrate that acute ethanol exerts a paradoxical dual impact on sleep-memory coupling in Drosophila. Typically, satiated flies require sleep for memory consolidation, but starved flies that must forage for food switch to sleep-independent memory. Ethanol selectively impairs memory consolidation in satiated flies, whereas memories in starved flies remain intact despite intoxication. The observed impairment in satiated flies is due to a switch to sleep-independent memory, which then cant be supported because of ethanol-induced sedation. Mechanistically, the ethanol-induced switch to sleep-independent memory is driven by neuropeptide F-mediated modulation of dopamine signaling. These findings reveal that ethanol intoxication inverts the canonical function of sleep, wherein it becomes detrimental to memory consolidation.