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Rapid-Eye-Movement-Sleep (REM) Associated Enhancement of Working Memory Performance after a Daytime Nap.

Lau EY, Wong ML, Lau KN, Hui FW, Tseng CH - PLoS ONE (2015)

Bottom Line: The two groups did not differ in their sleep characteristics prior to and after the lab visit.Within the Nap-group, working memory accuracy was positively correlated with duration of rapid eye movement sleep (REM) and total sleep time during the nap.Our findings suggested that "sleep gain" during a daytime sleep opportunity had significant positive impact on working memory performance, without affecting subsequent nighttime sleep in young adult, and such impact was associated with the duration of REM.

View Article: PubMed Central - PubMed

Affiliation: Sleep Laboratory, The University of Hong Kong, Hong Kong, China; Department of Psychology, The University of Hong Kong, Hong Kong, China; Department of Psychiatry, The University of Hong Kong, Hong Kong, China.

ABSTRACT
The main objective was to study the impact of a daytime sleep opportunity on working memory and the mechanism behind such impact. This study adopted an experimental design in a sleep research laboratory. Eighty healthy college students (Age:17-23, 36 males) were randomized to either have a polysomnography-monitored daytime sleep opportunity (Nap-group, n=40) or stay awake (Wake-group, n=40) between the two assessment sessions. All participants completed a sleep diary and wore an actigraph-watch for 5 days before and one day after the assessment sessions. They completed the state-measurement of sleepiness and affect, in addition to a psychomotor vigilance test and a working memory task before and after the nap/wake sessions. The two groups did not differ in their sleep characteristics prior to and after the lab visit. The Nap-group had higher accuracy on the working memory task, fewer lapses on the psychomotor vigilance test and lower state-sleepiness than the Wake-group. Within the Nap-group, working memory accuracy was positively correlated with duration of rapid eye movement sleep (REM) and total sleep time during the nap. Our findings suggested that "sleep gain" during a daytime sleep opportunity had significant positive impact on working memory performance, without affecting subsequent nighttime sleep in young adult, and such impact was associated with the duration of REM. While REM abnormality has long been noted in pathological conditions (e.g. depression), which are also presented with cognitive dysfunctions (e.g. working memory deficits), this was the first evidence showing working memory enhancement associated with REM in daytime napping in college students, who likely had habitual short sleep duration but were otherwise generally healthy.

No MeSH data available.


Related in: MedlinePlus

Association between Rapid-eye-movement-sleep duration with the pre/post-condition difference of 2-back Block 3 Accuracy.
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pone.0125752.g003: Association between Rapid-eye-movement-sleep duration with the pre/post-condition difference of 2-back Block 3 Accuracy.

Mentions: As the Nap-group was found to have significant improvement in the accuracy on the 2-back task across time, the association between the change in accuracy on the 2-back (from pre- to post-condition) and the polysomnographic measures were studied by correlational analyses. Details of the polysomnographic data were reported in Table 5. There were significant positive correlations between the change of 2-back block 3 accuracy with the total sleep time during the nap, r(40) = .315, p = .045 (Fig 2) and duration of REM, r(32) = .319, p = .042 (Fig 3). No other significant relationship was noted (Table 6).


Rapid-Eye-Movement-Sleep (REM) Associated Enhancement of Working Memory Performance after a Daytime Nap.

Lau EY, Wong ML, Lau KN, Hui FW, Tseng CH - PLoS ONE (2015)

Association between Rapid-eye-movement-sleep duration with the pre/post-condition difference of 2-back Block 3 Accuracy.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4430242&req=5

pone.0125752.g003: Association between Rapid-eye-movement-sleep duration with the pre/post-condition difference of 2-back Block 3 Accuracy.
Mentions: As the Nap-group was found to have significant improvement in the accuracy on the 2-back task across time, the association between the change in accuracy on the 2-back (from pre- to post-condition) and the polysomnographic measures were studied by correlational analyses. Details of the polysomnographic data were reported in Table 5. There were significant positive correlations between the change of 2-back block 3 accuracy with the total sleep time during the nap, r(40) = .315, p = .045 (Fig 2) and duration of REM, r(32) = .319, p = .042 (Fig 3). No other significant relationship was noted (Table 6).

Bottom Line: The two groups did not differ in their sleep characteristics prior to and after the lab visit.Within the Nap-group, working memory accuracy was positively correlated with duration of rapid eye movement sleep (REM) and total sleep time during the nap.Our findings suggested that "sleep gain" during a daytime sleep opportunity had significant positive impact on working memory performance, without affecting subsequent nighttime sleep in young adult, and such impact was associated with the duration of REM.

View Article: PubMed Central - PubMed

Affiliation: Sleep Laboratory, The University of Hong Kong, Hong Kong, China; Department of Psychology, The University of Hong Kong, Hong Kong, China; Department of Psychiatry, The University of Hong Kong, Hong Kong, China.

ABSTRACT
The main objective was to study the impact of a daytime sleep opportunity on working memory and the mechanism behind such impact. This study adopted an experimental design in a sleep research laboratory. Eighty healthy college students (Age:17-23, 36 males) were randomized to either have a polysomnography-monitored daytime sleep opportunity (Nap-group, n=40) or stay awake (Wake-group, n=40) between the two assessment sessions. All participants completed a sleep diary and wore an actigraph-watch for 5 days before and one day after the assessment sessions. They completed the state-measurement of sleepiness and affect, in addition to a psychomotor vigilance test and a working memory task before and after the nap/wake sessions. The two groups did not differ in their sleep characteristics prior to and after the lab visit. The Nap-group had higher accuracy on the working memory task, fewer lapses on the psychomotor vigilance test and lower state-sleepiness than the Wake-group. Within the Nap-group, working memory accuracy was positively correlated with duration of rapid eye movement sleep (REM) and total sleep time during the nap. Our findings suggested that "sleep gain" during a daytime sleep opportunity had significant positive impact on working memory performance, without affecting subsequent nighttime sleep in young adult, and such impact was associated with the duration of REM. While REM abnormality has long been noted in pathological conditions (e.g. depression), which are also presented with cognitive dysfunctions (e.g. working memory deficits), this was the first evidence showing working memory enhancement associated with REM in daytime napping in college students, who likely had habitual short sleep duration but were otherwise generally healthy.

No MeSH data available.


Related in: MedlinePlus