This study aims to elucidate the specific role of Rapid Eye Movement (REM) sleep, particularly its micro-architecture, in memory consolidation. While the importance of sleep for memory consolidation is well established, the focus has traditionally been on Non-Rapid Eye Movement (NREM) sleep. The distinct roles and interactions of the phasic and tonic substates of REM sleep in memory processes are less appreciated and are the focus of our current investigation. We employed a novel behavioral task, the Object Space Task (OST), to probe the neural underpinnings of simple and complex memory consolidation. Rodents underwent five trials interspersed with periods of sleep. To examine the effects of enhanced synaptic plasticity on memory consolidation and REM sleep architecture, we overexpressed the RGS14 protein in the prelimbic cortex. Conventionally, REM sleep in rodents has been considered a uniform state. However, our results highlight its diversity, as evidenced by distinct theta oscillation dynamics across different REM phases. Our initial results show that variations in REM sleep, particularly in the phasic REM following learning, are associated with task novelty. This correlation supports our hypothesis that REM sleep plays a crucial role in processing novel experiences. The study underscores the importance of REM sleep in the processing of novel events, simple and complex memories. This detailed understanding of the structure of REM sleep provides critical insights into the impact of learning on sleep architecture.