Human hippocampal ripples loosen medial prefrontal constraints to foster creative thinking

Creative thinking often requires breaking away from dominant mental schemas to generate novel and useful ideas. Yet how the human brain relaxes schematic constraints to enable creativity remains unclear. Using human intracranial EEG recordings, we found that moments of creative idea generation were accompanied by increased hippocampal ripple events, a concurrent reduction in ripple-triggered high-frequency activity in the medial prefrontal cortex (mPFC), and greater divergence of ripple-triggered mPFC activity patterns from the typical, schema-like task state. These effects followed a dorsal-ventral gradient within the mPFC and were most pronounced in the ventromedial PFC (vmPFC), a region heavily involved in schematic representation. Together, our findings suggest that hippocampal ripples can transiently disengage medial prefrontal schema constraints, thereby promoting more flexible and creative thinking.