Elucidating the role of sleep stages and GABAergic processes for cued memory reactivation during sleep

CARBONE JULIA; SUSANNE DIEKELMANN; BORN JAN; FORCATO CECILIA

Congreso; Neurowissenschaftliche Nachwuchskonferenz (NeNa 2018); 2018

Sleep plays a central role in memory formation, being particularly important for the consolidation of new information and its long-term storage. However, this consolidation process is not irreversible, since already consolidated memories can return to a labile state and be modified in the future by a process known as memory reconsolidation. In particular for human declarative memories, it was shown that consolidated memories canreturn to a labile state through reactivationby the presentation of a reminder cue(Forcato et al., 2009). Moreover, it was shown that cued memory reactivation during sleep stabilizes memories and enhances the performance (Diekelmannet al., 2011). Different sleep stages and neurotransmitters have been proposed to be involved in the process of memory formation during sleep. However, the exact mechanisms underlying this process are still unclear. The main goal of this project is to elucidate the specific function of single sleep stages and the neurotransmitter GABA for the formation of memories during sleep, particularly with regard to externally cued memory reactivation during sleep. For that we will use a sound-word association memory task that allows to reactivate with complete reminders (sound + complete word) and incomplete reminders (sound + first syllable of the word). We plan to perform 3 experiments with the following specific objectives: 1) Test if there is a difference in the performance when presenting reminder cues in different sleep stages, particularly when comparing N2 and SWS; 2) Test whether GABAergic activity modulates the memory-enhancing effects of different reminder types during these sleep stages by increasing GABAergic activity through the administration of Zolpidem (when compared to placebo condition); 3) Test if GABA is involved in the mechanisms underlying long-term stabilization and short-term strengtheningof memories upon reactivation with incomplete and complete reminders during sleep.