Sleep’s role in the reconsolidation of declarative memories

AbstractSleep is known to support the consolidation of newly encoded and initially labile memories. Once consolidated, remote memories can return to a labile state upon reactivation and need to become reconsolidated in order to persist. Here we asked whether sleep also benefits the reconsolidation of remote memories after their reactivation and how reconsolidation during sleep compares to sleep-dependent consolidation processes. In three groups, participants were trained on a visuo-spatial learning task in the presence of a contextual odor. Participants in the ‘reconsolidation’ group learned the task on day 1. On day 2, they were subjected to a reactivation procedure by presenting the odor cue and a mock recall test in the learning context before a 40-min sleep or wake period. Participants in the ‘remote consolidation’ group followed the same procedure but did not receive reactivation on day 2. Participants in the ‘recent consolidation’ group skipped the procedure on day 1 and learned the task immediately before the sleep or wake period. After the sleep or wake interval, memory stability was tested in all subjects. The results show that this short 40-min sleep period significantly facilitated the reconsolidation of reactivated memories, whereas the consolidation of non-reactivated remote memories was less affected and recently encoded memories did not benefit at all. These findings tentatively suggest that sleep has a beneficial effect on the reconsolidation of remote memories, acting at a faster rate than sleep-associated consolidation

Reactivation during sleep with incomplete reminder cues rather than complete ones stabilizes long-term memory in humans

Reactivation by reminder cues labilizes memories during wakefulness, requiring reconsolidation to persist. In contrast, during sleep, cued reactivation seems to directly stabilize memories. In reconsolidation, incomplete reminders are more effective in reactivating memories than complete reminders by inducing a mismatch, i.e. a discrepancy between expected and actual events. Whether mismatch is likewise detected during sleep is unclear. Here we test whether cued reactivation during sleep is more effective for mismatch-inducing incomplete than complete reminders. We first establish that only incomplete but not complete reminders labilize memories during wakefulness. When complete or incomplete reminders are presented during 40-min sleep, both reminders are equally effective in stabilizing memories. However, when extending the retention interval for another 7 hours (following 40-min sleep), only incomplete but not complete reminders stabilize memories, regardless of the extension containing wakefulness or sleep. We propose that, during sleep, only incomplete reminders initiate long-term memory stabilization via mismatch detection.Fil: Forcato, Cecilia. Instituto Tecnológico de Buenos Aires. Departamento de Investigación y Doctorado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Klinzing, Jens G.. Eberhard Karls Universität Tübingen; Alemania. University of Princeton; Estados UnidosFil: Carbone, Julia. Eberhard Karls Universität Tübingen; AlemaniaFil: Radloff, Michael. Eberhard Karls Universität Tübingen; AlemaniaFil: Weber, Frederik D.. Radboud Universiteit Nijmegen. Donders Instituto Brain Cognition and Behavior. SNN Machine Learning Group; Países BajosFil: Born, Jan. Eberhard Karls Universität Tübingen; AlemaniaFil: Diekelmann, Susanne. Eberhard Karls Universität Tübingen; Alemani

Sleep Loss Produces False Memories

People sometimes claim with high confidence to remember events that in fact never happened, typically due to strong semantic associations with actually encoded events. Sleep is known to provide optimal neurobiological conditions for consolidation of memories for long-term storage, whereas sleep deprivation acutely impairs retrieval of stored memories. Here, focusing on the role of sleep-related memory processes, we tested whether false memories can be created (a) as enduring memory representations due to a consolidation-associated reorganization of new memory representations during post-learning sleep and/or (b) as an acute retrieval-related phenomenon induced by sleep deprivation at memory testing. According to the Deese, Roediger, McDermott (DRM) false memory paradigm, subjects learned lists of semantically associated words (e.g., “night”, “dark”, “coal”,…), lacking the strongest common associate or theme word (here: “black”). Subjects either slept or stayed awake immediately after learning, and they were either sleep deprived or not at recognition testing 9, 33, or 44 hours after learning. Sleep deprivation at retrieval, but not sleep following learning, critically enhanced false memories of theme words. This effect was abolished by caffeine administration prior to retrieval, indicating that adenosinergic mechanisms can contribute to the generation of false memories associated with sleep loss

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Changing maladaptive memories through reconsolidation: A role for sleep in psychotherapy?

Like Lane et al., we believe that change in psychotherapy comes about by updating dysfunctional memories with new adaptive experiences. We suggest that sleep is essential to (re-)consolidate such corrective experiences. Sleep is well-known to strengthen and integrate new memories into pre-existing networks. Targeted sleep interventions might be promising tools to boost this process and thereby increase therapy effectiveness.Fil: Diekelmann, Susanne. Universität Tübingen; AlemaniaFil: Forcato, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin