Degree Programs in Medical Sciences, Graduate School of Comprehensive Human Sciences


Dr. Masashi Yanagisawa and his research group showed that the quality of prior waking experience greatly influences sleepiness


Dr. Masashi Yanagisawa, Director of the International Institute for Integrative Sleep Medicine, and his research group conducted experiments on mice using two different methods of 6-hour sleep deprivation, in which a dissociation of sleep need (ease of falling into a deep sleep) and level of arousal, or sleepiness, (ease of falling asleep) are observed. Sleepiness has been proven to vary depending on various experiences during waking. In addition, through a phosphor-proteomic approach, the research team has succeeded in identifying separate CNS biochemical signatures associated with sleep need and sleepiness.
These findings indicate that the quality of prior wakeful experience greatly influences sleepiness, even under conditions where levels of sleep need are the same. It is therefore surprising that such an obvious phenomenon seen in daily life has never been precisely and systematically studied at behavioral and biochemical levels in experimental animals until now. This paper proceeds to provide important insights into the way sleepiness is regulated, a fundamental question with general interest in neuroscience.
In collaboration with the University of Texas Southwestern Medical Center’s Ayako Suzki, Christopher M. Sinton, and Robert W. Greene (also a principal investigator at IIIS), this research was published in the Proceedings of the National Academy of Sciences in the United States of America (PNAS) on June 18, 2013.