Spontaneous reinstatement of episodic memories in the developing human brain

The hippocampus supports episodic memories in development, and yet how the brain stabilizes these memories determines their long-term accessibility. This study examined how episodic memories formed in development are stabilized and whether early-life experiences influence the neural mechanisms involved. Using fMRI and multivariate analyses, we tracked neural reinstatement of newly learned item-location-context associations in youth (N = 49; age_mean = 11.68 years). Hippocampus and visual cortex activity during encoding predicted later memory success. Crucially, spontaneous reinstatement in the medial prefrontal cortex (mPFC) during post-encoding rest also predicted memory. In a second sample (N = 32, age_mean = 12.86 years) with early adversity, differential recruitment of the precuneus and visual cortex during encoding, and angular gyrus during reinstatement, was observed. These findings suggest that hippocampus and mPFC contribute to developmental memory stabilization in ways consistent with mature function, while differences in memory accessibility across developmental experiences arise from broader network adaptations.