0092 Sleep Deprivation Leads to Fragmented Memory Loss. (12th April 2019)

• Record Type: Journal Article
• Authors: Ashton, Jennifer E; Harrington, Marcus O; Langthorne, Diane; Cairney, Scott A
• Is Part Of: Sleep. Volume 42(2019)Supplement 1
• Page Start: A38
• Page End: A38
• Publication Date: 2019-04-12
• Subjects: Sleep -- Physiological aspects -- Periodicals; Sleep disorders -- Periodicals; Sommeil -- Aspect physiologique -- Périodiques; Sommeil, Troubles du -- Périodiques; Sleep disorders; Sleep -- Physiological aspects; Sleep -- physiological aspects; Sleep Wake Disorders; Psychophysiology; Electronic journals; Periodicals; 616.8498
• DOI: 10.1093/sleep/zsz067.091
• Languages: English
• ISSNs: 0161-8105

Abstract

Abstract: Introduction: Forgetting is moderated by post-learning sleep, indicating that newly formed memories benefit from sleep-associated consolidation. Although rates of forgetting after a single day of wakefulness are well established, how prolonged periods of sleep deprivation impact on retrieval are unclear. Moreover, whether extended sleep restriction influences the qualitative nature of forgetting is yet to be established. In two experiments, we examined the effects of normal and protracted sleep loss on forgetting. Methods: Experiment One: 27 healthy adults (17 females, 20.85 ± 3.29 years), entered a repeated-measures study with two conditions (sleep and wake). In the sleep condition, learning and baseline memory assessment for adjective-image pairs took place before a night of sleep. Retrieval for the adjectives (item memory) and image categories (associative memory) was tested the following morning. In the wake condition, learning and testing took place in the morning and evening, respectively. Experiment Two: 28 healthy adults (24 females, 19.43 ± 1.32 years) completed the same procedures, but the test phase occurred in the morning after a night of sleep or 24 hours sleep deprivation. In both experiments, a follow-up test was included 48 hours later to assess longer-term impacts of sleep loss on forgetting. Results: Experiment One: item forgetting was higher after wakefulness than sleep ( F (1, 26)=5.67, p =.025, η 2 =.18), but there was no additional deficit in associative memory ( F (1, 26)=0.12, p =.73, η 2 =.01). No further differences were observed after 48 hours ( p >.05). Experiment Two: item forgetting was amplified after sleep deprivation relative to sleep ( F (1, 27)=20.53, p <.001, η 2 =.43). However, in contrast to normal wakefulness, extended overnight sleep loss led to a further impairment in associative memory ( F (1, 27)=10.30, p =.003, η 2 =.28). Moreover, a marginal increase in item forgetting was observed in the sleep deprivation condition 48 hours later ( F (1, 27)=3.57, p =.07, η 2 =.12). Conclusion: Item memories and their associations are lost or retained as composite representations after a normal period of wakefulness. However, prolonged sleep deprivation not only amplifies forgetting, but also appears to result in memory fragmentation, such that retained item memories lose their associative links. Support (If Any): Medical Research Council Career Development Award (MR/P020208/1) to S.A.C.