Sleep and memory.
Two experiments demonstrated that memory over an interval with relatively high amounts of rapid eye movement (REM) sleep was inferior to memory over an interval with relatively high amounts of stage 4 sleep. The results suggest that, at least for humans, REM sleep does not facilitate memory consolidation and that stage 4 sleep may be beneficial to memory.
D000328:Adult; D006801:Humans; D008568:Memory; D010153:Paired-Associate Learning; D012894:Sleep Stages; D012895:Sleep, REM; D013997:Time Factors