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Sleep loss produces false memories.

Diekelmann S, Landolt HP, Lahl O, Born J, Wagner U - PLoS ONE (2008)

Bottom Line: 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").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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany. diekelmann@kfg.uni-luebeck.de

ABSTRACT
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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Related in: MedlinePlus

Proportion of false memories in the recognition test.Under sleep deprivation at retrieval false memory rate was significantly enhanced in Experiment I (higher false memory rate in the sleep deprived “night wake” group compared to both non-deprived groups), while sleep after learning compared to wakefulness did not increase false memories (no difference between the “night sleep” and “day wake” group). Experiments II and III further strengthen these findings in showing that sleep deprivation at retrieval also enhanced false memory rate when “sleep vs. wakefulness after learning” was held constant and subjects only were or were not sleep deprived at retrieval (“2nd night wake” vs. “2nd night sleep” in Experiment II), and that sleep after learning neither enhanced false memories when retrieval was tested after a recovery night and controlling for circadian phase (“1st night wake” vs. “1st night sleep” in Experiment III). The administration of caffeine one hour before retrieval testing in Experiment IV abolished the sleep deprivation-induced enhancement in false memories. False memory rate refers to the mean proportion of the judgment “old” to 18 theme words that were not presented during learning (mean±SEM). * P<0.05, ** P<0.01.
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pone-0003512-g002: Proportion of false memories in the recognition test.Under sleep deprivation at retrieval false memory rate was significantly enhanced in Experiment I (higher false memory rate in the sleep deprived “night wake” group compared to both non-deprived groups), while sleep after learning compared to wakefulness did not increase false memories (no difference between the “night sleep” and “day wake” group). Experiments II and III further strengthen these findings in showing that sleep deprivation at retrieval also enhanced false memory rate when “sleep vs. wakefulness after learning” was held constant and subjects only were or were not sleep deprived at retrieval (“2nd night wake” vs. “2nd night sleep” in Experiment II), and that sleep after learning neither enhanced false memories when retrieval was tested after a recovery night and controlling for circadian phase (“1st night wake” vs. “1st night sleep” in Experiment III). The administration of caffeine one hour before retrieval testing in Experiment IV abolished the sleep deprivation-induced enhancement in false memories. False memory rate refers to the mean proportion of the judgment “old” to 18 theme words that were not presented during learning (mean±SEM). * P<0.05, ** P<0.01.

Mentions: Subjects of the “night wake” group who were acutely sleep deprived at retrieval testing exhibited significantly more false memories than subjects in the two other groups [F (2, 40) = 6.90; P = 0.003; Table 1; Figure 2]. After nocturnal wakefulness the proportion of falsely recognized theme words was on average 0.88±0.02, i.e. subjects falsely recognized 88% of the theme words, whereas after sleep and diurnal wakefulness false memory rate was 0.77±0.03 and 0.75±0.03, respectively (mean±SEM) [t (27) = 3.40, P = 0.002 and t (27) = 4.01, P<0.001, for pair-wise comparisons]. Importantly, subjects did not produce more false memories in the “night sleep” group than in the “day wake” group, which would be expected if consolidation processes during post-learning sleep were critical for the development of false memories [t (26) = 0.46, P>0.60]. There was no difference between the three groups in hit rates (correctly recognized words) [F (2, 40) = 0.78, P>0.40] and false alarm rates (falsely recognized distractor words) [F (2, 40) = 1.18, P>0.30] (Table 1). To exclude that increased false memory generation after sleep deprivation merely resulted from enhanced baseline propensity to accept items, additional analyses were performed with the discrimination index Pr and the response bias index Br according to the two-high threshold model of recognition memory as dependent variables ([25]; see Materials and Methods, for details). In these analyses, sleep deprived subjects likewise exhibited significantly more false memories compared to both non-deprived control groups [Pr = 0.67±0.04, 0.50±0.04 and 0.47±0.04, for the “night wake”, “night sleep” and “day wake” group, respectively; F (2, 40) = 8.69, P = 0.001], whereas correct recognition memory again did not differ between groups [Pr = 0.51±0.04, 0.40±0.04 and 0.42±0.04, for the “night wake”, “night sleep” and “day wake” group, respectively; F (2, 40) = 2.05, P>0.14]. The response bias, either for false recognition or correct recognition, also did not differ between groups [false recognition: Br = 0.63±0.06, 0.55±0.06 and 0.53±0.06; correct recognition: Br = 0.40±0.04, 0.45±0.04 and 0.47±0.04; both F (2, 40)<1.20, P>0.30].


Sleep loss produces false memories.

Diekelmann S, Landolt HP, Lahl O, Born J, Wagner U - PLoS ONE (2008)

Proportion of false memories in the recognition test.Under sleep deprivation at retrieval false memory rate was significantly enhanced in Experiment I (higher false memory rate in the sleep deprived “night wake” group compared to both non-deprived groups), while sleep after learning compared to wakefulness did not increase false memories (no difference between the “night sleep” and “day wake” group). Experiments II and III further strengthen these findings in showing that sleep deprivation at retrieval also enhanced false memory rate when “sleep vs. wakefulness after learning” was held constant and subjects only were or were not sleep deprived at retrieval (“2nd night wake” vs. “2nd night sleep” in Experiment II), and that sleep after learning neither enhanced false memories when retrieval was tested after a recovery night and controlling for circadian phase (“1st night wake” vs. “1st night sleep” in Experiment III). The administration of caffeine one hour before retrieval testing in Experiment IV abolished the sleep deprivation-induced enhancement in false memories. False memory rate refers to the mean proportion of the judgment “old” to 18 theme words that were not presented during learning (mean±SEM). * P<0.05, ** P<0.01.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2567433&req=5

pone-0003512-g002: Proportion of false memories in the recognition test.Under sleep deprivation at retrieval false memory rate was significantly enhanced in Experiment I (higher false memory rate in the sleep deprived “night wake” group compared to both non-deprived groups), while sleep after learning compared to wakefulness did not increase false memories (no difference between the “night sleep” and “day wake” group). Experiments II and III further strengthen these findings in showing that sleep deprivation at retrieval also enhanced false memory rate when “sleep vs. wakefulness after learning” was held constant and subjects only were or were not sleep deprived at retrieval (“2nd night wake” vs. “2nd night sleep” in Experiment II), and that sleep after learning neither enhanced false memories when retrieval was tested after a recovery night and controlling for circadian phase (“1st night wake” vs. “1st night sleep” in Experiment III). The administration of caffeine one hour before retrieval testing in Experiment IV abolished the sleep deprivation-induced enhancement in false memories. False memory rate refers to the mean proportion of the judgment “old” to 18 theme words that were not presented during learning (mean±SEM). * P<0.05, ** P<0.01.
Mentions: Subjects of the “night wake” group who were acutely sleep deprived at retrieval testing exhibited significantly more false memories than subjects in the two other groups [F (2, 40) = 6.90; P = 0.003; Table 1; Figure 2]. After nocturnal wakefulness the proportion of falsely recognized theme words was on average 0.88±0.02, i.e. subjects falsely recognized 88% of the theme words, whereas after sleep and diurnal wakefulness false memory rate was 0.77±0.03 and 0.75±0.03, respectively (mean±SEM) [t (27) = 3.40, P = 0.002 and t (27) = 4.01, P<0.001, for pair-wise comparisons]. Importantly, subjects did not produce more false memories in the “night sleep” group than in the “day wake” group, which would be expected if consolidation processes during post-learning sleep were critical for the development of false memories [t (26) = 0.46, P>0.60]. There was no difference between the three groups in hit rates (correctly recognized words) [F (2, 40) = 0.78, P>0.40] and false alarm rates (falsely recognized distractor words) [F (2, 40) = 1.18, P>0.30] (Table 1). To exclude that increased false memory generation after sleep deprivation merely resulted from enhanced baseline propensity to accept items, additional analyses were performed with the discrimination index Pr and the response bias index Br according to the two-high threshold model of recognition memory as dependent variables ([25]; see Materials and Methods, for details). In these analyses, sleep deprived subjects likewise exhibited significantly more false memories compared to both non-deprived control groups [Pr = 0.67±0.04, 0.50±0.04 and 0.47±0.04, for the “night wake”, “night sleep” and “day wake” group, respectively; F (2, 40) = 8.69, P = 0.001], whereas correct recognition memory again did not differ between groups [Pr = 0.51±0.04, 0.40±0.04 and 0.42±0.04, for the “night wake”, “night sleep” and “day wake” group, respectively; F (2, 40) = 2.05, P>0.14]. The response bias, either for false recognition or correct recognition, also did not differ between groups [false recognition: Br = 0.63±0.06, 0.55±0.06 and 0.53±0.06; correct recognition: Br = 0.40±0.04, 0.45±0.04 and 0.47±0.04; both F (2, 40)<1.20, P>0.30].

Bottom Line: 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").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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany. diekelmann@kfg.uni-luebeck.de

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus