Spontaneous reinstatement of episodic memories in the developing human brain

Starting early in development, the hippocampus can support the formation of episodic memories, and yet how the developing brain stabilizes these memories to support their long-term accessibility has not been established. This study (N = 49; mean age = 11.68 years) examined how encoded episodic memories are stabilized in development. Using fMRI and multivariate analyses, we tracked neural reinstatement of newly learned item-location-context associations in youth. During encoding, hippocampus and visual cortex activity predicted later memory success. Crucially, during post-encoding rest, spontaneous pattern reinstatement in the angular gyrus and the pregenual medial prefrontal cortex (mPFC) also predicted memory, with age-related changes in the mPFC and superior frontal gyrus. These findings suggest that episodic memory stabilization during childhood and adolescence is broadly supported by developmental change within regions associated with mature function, advancing our understanding of how different memory stages contribute to how we learn and remember across the lifespan.