Sharp wave ripples (SWR) represent synchronized activity of neuronal population in the mammalian hippocampus. They are thought to be associated with memory reactivation, transfer, and consolidation during sleep and awake immobility. In adults, it was shown that some subtypes of SWR are triggering precise activation across cortical areas accompanied by strong inhibition in subcortical areas (Logothetis et. al. 2012, Pedrosa et. al 2022) while other subtypes preferentially activates neuromodulatory structures such as the dorsal raphe nucleus and the locus coeruleus (Ramirez-Villega et. al 2015). The hippocampal-cortical interplay during periods of subcortical silence is thought to enable hippocampus dependent memory consolidation with minimal interference. However, we know very little about the developmental timeline of these inter-regional coupling (hippocampo-cortical or hippocampo-subcortical). Here, by simultaneously recording electrophysiological signals from hippocampal and cortical areas across sleep in freely behaving animals from postnatal day P9 to P60, we will investigate how early in the development we can identify diverse SWR subtypes. We will then characterize their maturation timeline both in terms of activation and recruitment patterns locally in the hippocampus, as well as through associated cortical activation patterns. We will specifically test whether distinct subtypes of SWR emerge at different timepoints, potentially linked to local circuit maturation. Such results will provide some of the neural basis necessary to understand the age-specific nature of distinct memory processes.