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To sleep, to strive, or both: how best to optimize memory.

Tucker MA, Tang SX, Uzoh A, Morgan A, Stickgold R - PLoS ONE (2011)

Bottom Line: Over an extended 24 hr interval we found 1) that an initial night of sleep partially protects memories from subsequent deterioration during wake, and 2) that sleep blocks further deterioration, and may even have a restorative effect on memory, when it follows a full day of wake.Interestingly, the benefit imparted to rewarded (relative to unrewarded) stimuli was equal for sleep and wake subjects, suggesting that the sleeping brain may not differentially process rewarded information, relative to wake.However, looking at the overall impact of sleep relative to reward in this protocol, it was apparent that sleep both imparted a stronger mnemonic boost than reward, and provided a benefit to memory regardless of whether it occurred in the first or the second 12 hrs following task training.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, United States of America. mtucker1@bidmc.harvard.edu

ABSTRACT
While numerous studies have shown that a night of sleep profits memory relative to wake, we still have little understanding about what factors mediate this effect of sleep. A clear understanding of the dynamics of this effect of sleep beyond the initial night of sleep is also lacking. Here, we examined the effect of extrinsic rewards on sleep-dependent declarative memory processing across 12 and 24 hr training-retest intervals. Subjects were either paid based on their performance at retest ($1 for each correct answer), or received a flat fee for participation. After a 12 hr interval we observed pronounced benefits of both sleep and reward on memory. Over an extended 24 hr interval we found 1) that an initial night of sleep partially protects memories from subsequent deterioration during wake, and 2) that sleep blocks further deterioration, and may even have a restorative effect on memory, when it follows a full day of wake. Interestingly, the benefit imparted to rewarded (relative to unrewarded) stimuli was equal for sleep and wake subjects, suggesting that the sleeping brain may not differentially process rewarded information, relative to wake. However, looking at the overall impact of sleep relative to reward in this protocol, it was apparent that sleep both imparted a stronger mnemonic boost than reward, and provided a benefit to memory regardless of whether it occurred in the first or the second 12 hrs following task training.

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Sleep and Reward effects.A. Sleep v. Wake performance at 12 and 24 hrs. B. Reward v. No-Reward performance at 12 and 24 hrs. Bars represent change in recall collapsed across reward condition (means±SEMs).
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pone-0021737-g004: Sleep and Reward effects.A. Sleep v. Wake performance at 12 and 24 hrs. B. Reward v. No-Reward performance at 12 and 24 hrs. Bars represent change in recall collapsed across reward condition (means±SEMs).

Mentions: Data for the individual 12 hr groups are presented in Figure 3A. We observed independent benefits from Sleep and Reward, such that subjects in the 12 hr Sleep+Reward condition performed best, actually improving their performance by 0.6 picture pairs (+2.4%) at retest (p = .21), while the 12 hr Wake+No Reward group performed worst, forgetting 4.1 pairs (17.0%; p<.0001; Figure 3A). Overall, there was a robust memory advantage at 12 hr retest for subjects who slept, with the 2-way ANOVA of condition (Sleep v. Wake)×reward (Reward v. No-Reward) revealing a highly significant main effect of condition (F1,73 = 34.09, p<.0001, η2p = .32; Figure 4A, left). Specifically, wake subjects forgot 3.3±0.4 (14.2%) pairs (t36 = 8.14, p<.0001), while sleep subjects demonstrated highly preserved memory, forgetting only 0.1±0.4 (0.4%) picture pairs (t37 = .21, p = .84).


To sleep, to strive, or both: how best to optimize memory.

Tucker MA, Tang SX, Uzoh A, Morgan A, Stickgold R - PLoS ONE (2011)

Sleep and Reward effects.A. Sleep v. Wake performance at 12 and 24 hrs. B. Reward v. No-Reward performance at 12 and 24 hrs. Bars represent change in recall collapsed across reward condition (means±SEMs).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3140493&req=5

pone-0021737-g004: Sleep and Reward effects.A. Sleep v. Wake performance at 12 and 24 hrs. B. Reward v. No-Reward performance at 12 and 24 hrs. Bars represent change in recall collapsed across reward condition (means±SEMs).
Mentions: Data for the individual 12 hr groups are presented in Figure 3A. We observed independent benefits from Sleep and Reward, such that subjects in the 12 hr Sleep+Reward condition performed best, actually improving their performance by 0.6 picture pairs (+2.4%) at retest (p = .21), while the 12 hr Wake+No Reward group performed worst, forgetting 4.1 pairs (17.0%; p<.0001; Figure 3A). Overall, there was a robust memory advantage at 12 hr retest for subjects who slept, with the 2-way ANOVA of condition (Sleep v. Wake)×reward (Reward v. No-Reward) revealing a highly significant main effect of condition (F1,73 = 34.09, p<.0001, η2p = .32; Figure 4A, left). Specifically, wake subjects forgot 3.3±0.4 (14.2%) pairs (t36 = 8.14, p<.0001), while sleep subjects demonstrated highly preserved memory, forgetting only 0.1±0.4 (0.4%) picture pairs (t37 = .21, p = .84).

Bottom Line: Over an extended 24 hr interval we found 1) that an initial night of sleep partially protects memories from subsequent deterioration during wake, and 2) that sleep blocks further deterioration, and may even have a restorative effect on memory, when it follows a full day of wake.Interestingly, the benefit imparted to rewarded (relative to unrewarded) stimuli was equal for sleep and wake subjects, suggesting that the sleeping brain may not differentially process rewarded information, relative to wake.However, looking at the overall impact of sleep relative to reward in this protocol, it was apparent that sleep both imparted a stronger mnemonic boost than reward, and provided a benefit to memory regardless of whether it occurred in the first or the second 12 hrs following task training.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, United States of America. mtucker1@bidmc.harvard.edu

ABSTRACT
While numerous studies have shown that a night of sleep profits memory relative to wake, we still have little understanding about what factors mediate this effect of sleep. A clear understanding of the dynamics of this effect of sleep beyond the initial night of sleep is also lacking. Here, we examined the effect of extrinsic rewards on sleep-dependent declarative memory processing across 12 and 24 hr training-retest intervals. Subjects were either paid based on their performance at retest ($1 for each correct answer), or received a flat fee for participation. After a 12 hr interval we observed pronounced benefits of both sleep and reward on memory. Over an extended 24 hr interval we found 1) that an initial night of sleep partially protects memories from subsequent deterioration during wake, and 2) that sleep blocks further deterioration, and may even have a restorative effect on memory, when it follows a full day of wake. Interestingly, the benefit imparted to rewarded (relative to unrewarded) stimuli was equal for sleep and wake subjects, suggesting that the sleeping brain may not differentially process rewarded information, relative to wake. However, looking at the overall impact of sleep relative to reward in this protocol, it was apparent that sleep both imparted a stronger mnemonic boost than reward, and provided a benefit to memory regardless of whether it occurred in the first or the second 12 hrs following task training.

Show MeSH