title: Sex-Related Differences in the Effects of Sleep Habits on Verbal and Visuospatial Working Memory.
abstract: Poor sleep quality negatively affects memory performance, and working memory in particular. We investigated sleep habits related to sleep quality including sleep duration, daytime nap duration, nap frequency, and dream content recall frequency (DCRF). Declarative working memory can be subdivided into verbal working memory (VWM) and visuospatial working memory (VSWM). We hypothesized that sleep habits would have different effects on VWM and VSWM. To our knowledge, our study is the first to investigate differences between VWM and VSWM related to daytime nap duration, nap frequency, and DCRF. Furthermore, we tested the hypothesis that the effects of duration and frequency of daytime naps and DCRF on VWM and VSWM differed according to sex. We assessed 779 healthy right-handed individuals (434 males and 345 females; mean age: 20.7 ± 1.8 years) using a digit span forward and backward VWM task, a forward and backward VSWM task, and sleep habits scales. A correlation analysis was used to test the relationships between VWM capacity (VWMC) and VSWM capacity (VSWMC) scores and sleep duration, nap duration, nap frequency, and DCRF. Furthermore, multiple regression analyses were conducted to identify factors associated with VWMC and VSWMC scores and to identify sex-related differences. We found significant positive correlations between VSWMC and nap duration and DCRF, and between VWMC and sleep duration in all subjects. Furthermore, we found that working memory capacity (WMC) was positively correlated with nap duration in males and with sleep duration in females, and DCRF was positively correlated with VSWMC in females. Our finding of sex-related differences in the effects of sleep habits on WMC has not been reported previously. The associations between WMC and sleep habits differed according to sex because of differences in the underlying neural correlates of VWM and VSWM, and effectiveness of the sleep habits in males and females.
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Department of Psychiatry, Tohoku Medical and Pharmaceutical UniversitySendai, Japan.
authors: Seishu
authors: S
authors: Nakagawa
authors: Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Hikaru
authors: H
authors: Takeuchi
authors: Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Division of Medical Neuroimaging Analysis, Department of Community Medical Supports, Tohoku Medical Megabank Organization, Tohoku UniversitySendai, Japan; Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan.
authors: Yasuyuki
authors: Y
authors: Taki
authors: Creative Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Science, Tohoku UniversitySendai, Japan; Human and Social Response Research Division, International Research Institute of Disaster Science, Tohoku UniversitySendai, Japan; Smart Ageing International Research Center, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan.
authors: Rui
authors: R
authors: Nouchi
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Division of Medical Neuroimaging Analysis, Department of Community Medical Supports, Tohoku Medical Megabank Organization, Tohoku UniversitySendai, Japan; Department of Adult Mental Health, National Institute of Mental Health, National Center of Neurology and PsychiatryTokyo, Japan.
authors: Atsushi
authors: A
authors: Sekiguchi
authors: Smart Ageing International Research Center, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Yuka
authors: Y
authors: Kotozaki
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Department of General Systems Studies, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan.
authors: Carlos M
authors: CM
authors: Miyauchi
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Department of Psychiatry, Tohoku University Graduate School of MedicineSendai, Japan.
authors: Kunio
authors: K
authors: Iizuka
authors: School of Medicine, Kobe UniversityKobe, Japan; Japan Society for the Promotion of ScienceTokyo, Japan.
authors: Ryoichi
authors: R
authors: Yokoyama
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Takamitsu
authors: T
authors: Shinada
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Yuki
authors: Y
authors: Yamamoto
authors: Department of Human Brain Science, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Sugiko
authors: S
authors: Hanawa
authors: ADVANTAGE Risk Management Co., Ltd Tokyo, Japan.
authors: Tsuyoshi
authors: T
authors: Araki
authors: Faculty of Medicine, Tohoku University Sendai, Japan.
authors: Keiko
authors: K
authors: Kunitoki
authors: Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University Sendai, Japan.
authors: Yuko
authors: Y
authors: Sassa
authors: Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Smart Ageing International Research Center, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan; Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku UniversitySendai, Japan.
authors: Ryuta
authors: R
authors: Kawashima
keywords: dream content remembering frequency (DCRF); nap duration; sleep duration; verbal working memory capacity (VWMC); visuospatial working memory capacity (VSWMC)