TY - JOUR
T1 - Rapid-eye-movement-sleep (REM) associated enhancement of working memory performance after a daytime nap
AU - Lau, Esther Yuet Ying
AU - Wong, Mark Lawrence
AU - Lau, Kristy Nga Ting
AU - Hui, Florence Wai Ying
AU - Tseng, Chia Huei
N1 - Funding Information:
This study was supported by the HKU Seed Funding Program for Basic Research. All the research activities were conducted at the University of Hong Kong, Hong Kong, China. Our sincere gratitude goes to Professor Gail Eskes for providing the n-back program and to MindSea Development Inc. for writing the software. We thank the editor, Dr. Reffaele Ferri and the anonymous reviewers for their constructive comments on the earlier versions of the manuscript. We would like to thank Camus Chiang for PSG scoring and Cecilia Leung, Gervais Leung, Phoebe Hung, Edith Lee, Wing-Lan Lee, Jacqueline Choi, Shirley Wong, Moon Ho, Lucie Siu and Martin Chan for their assistance in data collection.
Publisher Copyright:
© 2015 Lau et al.
PY - 2015/5/13
Y1 - 2015/5/13
N2 - 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 (Napgroup, 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 Wakegroup. 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.
AB - 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 (Napgroup, 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 Wakegroup. 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.
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U2 - 10.1371/journal.pone.0125752
DO - 10.1371/journal.pone.0125752
M3 - Article
C2 - 25970511
AN - SCOPUS:84929376778
VL - 10
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 5
M1 - e0125752
ER -