Reactivation of declarative memory during sleep

Lead Research Organisation: University of York
Department Name: Psychology

Abstract

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Publications

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Description 1)'The Benefits of Targeted Memory Reactivation for Consolidation in Sleep are Contingent on Memory Accuracy and Direct Cue-Memory Associations'. In press, SLEEP.

We examined how targeted memory reactivation (TMR) is influenced by memory accuracy prior to sleep and the presence or absence of direct cue-memory associations. Participants associated pictures with unrelated words and screen locations in separate tasks. During picture-location training, each picture was also presented with a semantically related sound. Sounds were therefore directly associated with the picture locations but indirectly associated with the words. Half of the sounds were replayed in slow wave sleep (SWS). There was a benefit of TMR for picture locations recalled with low accuracy prior to sleep, but not those recalled accurately. There was no benefit of TMR for picture-word pairs. The benefits of TMR are therefore contingent on memories being weakly encoded and directly associated with the reactivation cues.

2) 'Targeted memory reactivation: the effects of cue type and acoustic match'. In preparation, Journal of Cognitive Neuroscience.

While both environmental sounds and spoken words have been used in prior studies of TMR, the relative effectiveness of these cue types has yet to be examined. Moreover, whether spoken reactivation cues need to be a veridical acoustic match to the original cue for successful TMR is unknown. Participants were trained to associate environmental sounds and spoken words with unrelated visually presented words. The sounds and words associated with half of the items were replayed during SWS. Importantly, the words replayed in sleep were either acoustically identical or different. Sound and identical word cues brought comparable benefits for memory performance. However, the success of TMR critically depended on the acoustic match between learning materials and reactivation cues.

3) 'Consolidation during sleep preserves original memories over distorted variations' In preparation, Learning and Memory.

Retrieval involves the storage of retrieved information, often inducing memory distortion. We examined whether sleep-dependent consolidation processes support the preservation of newly-acquired memories or strengthen distorted variations of the same memories following retrieval. Participants encoded object locations and were then tested before (T1) and after (T2) sleep or wakefulness. Retrieval at T1 distorted memory at T2 but this effect was not enhanced over sleep. However, memory for the encoded object locations was more accurate after sleep than wakefulness, indicating that sleep had preserved memories in their original form.

4) 'Reactivation does not facilitate integration of new memories' In progress.

We used novel words to determine the extent to which TMR can influence the recall of new forms and the integration between new and existing knowledge. Data collection is not quite complete on this project, but the preliminary data suggest that TMR acts as a block to integration of new memories. This finding, if it applies to the full dataset, would suggest that TMR is not a good model of systems consolidation but instead acts to facilitate memory within the hippocampus.
Exploitation Route The findings of of substantial value to the understanding of mechanisms of consolidation of memories during sleep. We are exploring in collaboration with other research groups in the area, the possibility of gaining funding to exploit these results in a more applied domain.
Sectors Education,Healthcare

 
Description The research in the grant has formed the basis of a more applied strand of research employing techniques developed in the grant. More specifically, the researcher on the grant has won two competitive awards, the second being an MRC Career Development Fellowship to address the potential for slow oscillation stimulation during sleep to influence emotional wellbeing. The intention of the award is to conduct research that might one day form part of a therapy for disorders with an emotional component. This is a substantial move towards societal impact of the research, but of course the end product is still several years away.
First Year Of Impact 2014
Sector Other
 
Description Career Development Fellow (Cairney)
Amount £1,400,000 (GBP)
Organisation Medical Research Council (MRC) 
Sector Academic/University
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 10/2017 
End 09/2022