Sleep enhances spatial schema memory formation in humans

Schema memory, a generalized representation formed across episodes sharing regularities, is thought to arise through sleep-dependent systems consolidation. Yet, direct evidence in humans remains sparse. Here, sixty young adults navigated a virtual-reality arena and learned a spatial distribution of object-category ratios across five sessions (toys vs. household items, hidden in boxes at different locations). Participants then either slept or were sleep-deprived for a full night, followed by two recovery nights before memory testing, or they were tested after a short 30-min delay spent awake. Only after a three-day delay did spatial memory of old box locations predict spatial interpolation to new box locations, indicating time-dependent schema expression. Critically, sleep distinctly enhanced spatial integration beyond the effect of time. This benefit was predicted by frontal cortical slow oscillation-spindle coupling during the first post-encoding night, thus linking sleep oscillations to the transformation of episodic spatial memories into integrated schema representations.