RESUMEN
REM sleep has a role in memory processing. The period of post-learning, that REM sleep is higher than normal level and deprivation of REM sleep impairs memory, is called paradoxical sleep windows [PSW]. In this experimental study, male N.M.RI rats were trained in a two-way shuttle avoidance task [100 trials/one sessions] then memory retention was tested in next week. In electrophysiology section, different sleep-memory factors were recorded in basal level and 1-4 hours after training. In behavioral section, animals that reached 70% learning criterion [learner group] were deprived of PS in the two periods of 1-4 hours and 5-8 hours after learning by Maze water technique. The amount of REM sleep in group which gained 70% learning after 1-4 hours training, and group without it. In v.s of basic level, significantly increase [p<0.01]. Other factors were showed no significant difference between two groups before training. In behavioral section those animals were deprived in 1-4 hr post-learning show significant memory impairment [p<0.05]. Paradoxical increased REM sleep is effective in memory consolidation after 1-4 hours training. This period can be consider as paradoxical sleep window