Augmenting hippocampal-prefrontal neuronal synchrony during sleep enhances memory consolidation in humans

This study investigated the causal relationship between hippocampal-prefrontal neuronal synchrony during sleep and memory consolidation in humans. Using real-time closed-loop deep brain stimulation in the prefrontal cortex during sleep, researchers found that synchronizing stimulation to medial temporal lobe (MTL) slow waves enhanced sleep spindles, boosted neural spiking activity locking to MTL slow waves, and improved coupling between MTL ripples and thalamocortical oscillations. This synchronized stimulation also enhanced recognition memory accuracy. Conversely, identical stimulation without precise time-locking did not improve, and sometimes degraded, these effects. Individual memory improvements correlated highly with electrophysiological changes. These results indicate that hippocampo-thalamocortical synchronization during sleep causally supports human memory consolidation.

Maya Geva-Sagiv, Emily A. Mankin, Dawn Eliashiv, Shdema Epstein, Natalie Cherry, Guldamla Kalender, Natalia Tchemodanov, Yuval Nir, Itzhak Fried