Podcast with Luis Fuentemilla on memory consolidation and sleep

How does the brain decide what to remember and what to forget , even while you sleep? Memory researcher Luis Fuentemilla reveals that targeted reactivation during slow-wave sleep can boost or suppress specific memories, and that the sleeping brain actively distinguishes between competing memory traces using different neural signatures. Subscribe for more from the Convergent Science Network podcast series. Luis Fuentemilla joins Paul Verschure and Tony Prescott to explore the mechanisms by which fleeting experience becomes lasting memory. He frames memory not as a simple recording device but as the function that links moment to moment into continuity , shaping perception, enabling mental time travel, and constructing the self. The conversation centers on the dual-process model of memory consolidation, where a fast hippocampal system captures experiences and a slow cortical system gradually absorbs them through offline replay during sleep. Fuentemilla describes experiments using targeted memory reactivation: sounds paired with specific stimuli during learning are replayed during slow-wave sleep, producing roughly a ten percent improvement in recall for reactivated items. The critical finding is that reactivation must occur during slow-wave sleep, not REM, because this is when hippocampal-cortical coupling is strongest and the brain is maximally disconnected from external input. Even more striking, when competing memories are reactivated, the sleeping brain generates distinct neural oscillatory responses depending on whether the memory will be strengthened or suppressed, suggesting an active organizational process rather than passive decay. Key topics include why most episodic memories from daily life are effectively forgotten, how wearable camera studies reveal the limits of autobiographical recall, the relationship between memory replay and systems-level consolidation, whether replay faithfully reproduces original neural patterns or transforms them, and how competition between overlapping memory traces may drive active forgetting during sleep. Part of the Convergent Science Network podcast series from the BCBT Summer School.