Spindle-locked ripples mediate memory reactivation during human NREM sleep

Memory consolidation involves reactivation of prior experiences during sleep. While the interplay of slow oscillations, spindles, and ripples is thought to coordinate this process, with ripples mediating reactivation, human evidence is lacking. This study used targeted memory reactivation (TMR) with intracranial EEG in epilepsy patients and scalp EEG in healthy participants. Increased slow oscillation-related spindle activity coincided with memory reactivation. Importantly, spindle-locked ripples in the medial temporal lobe (MTL) correlated with successful memory reactivation during NREM sleep. This confirms ripples' crucial role in sleep-related memory reactivation in humans and highlights the coordinated interplay of sleep oscillations.

Tobias Schreiner, Moritz Petzka, Benjamin Gänger, Christine Vollmar, Elisabeth Kaufmann, Julian Noachtar, Johannes Ries, Tobias Staudigl