BackgroundSleep deprivation impairs core cognitive functions, such as working memory. Previous studies focused on global working memory performance, and direct comparisons of how different cognitive enhancers mitigate sleep deprivation-induced deficits in object working memory remain limited, particularly regarding the underlying neurophysiological mechanisms. This study compared the counteractive effects of caffeine and modafinil after 36 h of total sleep deprivation and elucidated their stage-