Schemas provide a scaffold for neocortical integration at the cost of memory specificity over time

SUMMARY Memory transformation is increasingly acknowledged in theoretical accounts of systems consolidation, yet how memory quality and neural representation change over time and how schemas influence this process remains unclear. In this fMRI study, participants encoded and retrieved schema-congruent and incongruent object-scene pairs using a paradigm that probed coarse and detailed memories over 10-minutes and 72-hours. When a congruent schema was available, details were lost over time as representations were integrated in the medial prefrontal cortex (mPFC), and enhanced post-encoding coupling between the anterior hippocampus and mPFC was associated with coarser memories. Over time, pattern similarity in the hippocampus changed such that the posterior hippocampus represented specific details and the anterior hippocampus represented the general context of specific memories, irrespective of congruency. Our findings suggest schemas are used as a scaffold for accelerated consolidation of congruent information, and illustrate change in hippocampal organization of detailed contextual memory over time.