Ponente invitad@: Daniel Baena. The active role of sleep in memory consolidation: insights from simultaneous EEG–fMRI

What: The active role of sleep in memory consolidation: insights from simultaneous EEG–fMRI

Where: BCBL Auditorium and Auditorium zoom room (If you would like to attend to this meeting reserve at info@bcbl.eu)

Who: Daniel Baena, PhD, Postdoctoral Researcher, BCBL.

When:  Thursday,  Dec 4th at 12:00 PM noon.

Sleep is increasingly recognized as an active period during which the brain reorganizes recently learned information. Yet, the specific mechanisms supporting this reorganization remain poorly understood. In this talk, I will present a series of studies using simultaneous EEG–fMRI to examine how the sleeping brain reactivates memory-related networks. The results indicate a key mechanism: the precise timing between slow waves and sleep spindles, known as slow wave–spindle (SW–SP) coupling. First, I will show that coupled and uncoupled spindles reflect different processes: only coupled events activate hippocampal and fronto-striatal regions linked to prior learning, whereas uncoupled spindles mainly recruit sensory areas. This difference shows that coupling is the feature that determines which information is replayed. Second, I will present evidence that the association between sleep spindles and fluid intelligence depends on how precisely spindles align with slow waves. Third, I will show that coupled events reinstate the motor and subcortical networks used during motor learning, with clear hemispheric specificity. A fourth line of work shows that older adults have fewer and less precise coupled events, and gain less from sleep. Importantly, the amount of preserved coupling predicts how much they continue to consolidate newly acquired skills. Finally, I will explain why these effects can only be observed with EEG–fMRI, and describe recent methodological developments that improve the consistency and reliability of coupling measures. Together, these findings show that SW–SP coupling is a central mechanism through which sleep supports memory and cognition across the lifespan.