Yu Hayashi

Affiliation:International Institute for Integrative Sleep Medicine, University of Tsukuba

Research Title


Addressing the functional roles and evolutionary origin of sleep

01 Research Summary

Sleep is indispensable. However, the function of sleep remains largely unknown. During sleep, the level of consciousness is lowered and the risk of being attacked by predators increases. Yet most animals undergo sleep, suggesting that sleep plays some conserved vital roles. We address the function and evolutionary origin of sleep using the roundworm Caenorhabditis elegans and mouse. The nervous system of C. elegans consists of merely 302 neurons. We previously obtained evidence suggesting that sleep in this simple animal and mammalian sleep are evolutionarily conserved. Furthermore, in mice, we successfully identified neurons that are crucial for the regulation of REM sleep, the major source of vivid dreams, and established mice where REM sleep could be efficiently inhibited. Using these two model animals, we aim to elucidate the roles of sleep at multiple levels from molecular and cellular to individual levels.


Hayashi Laboratory

02 Major achievements

Hiromasa Funato, Chika Miyoshi*, Tomoyuki Fujiyama*, Takeshi Kanda*, Makito Sato*, Zhiqiang Wang, Jing Ma, Shin Nakane, Jun Tomita, Aya Ikkyu, Miyo Kakizaki, Noriko Hotta-Hirashima,Satomi Kanno, Haruna Komiya, Fuyuki Asano, Takato Honda, Staci J. Kim, Kanako Harano, Hiroki Muramoto, Toshiya Yonezawa, Seiya Mizuno, Shinichi Miyazaki, Linzi Connor, Vivek Kumar, Ikuo Miura, Tomohiro Suzuki, Atsushi Watanabe, Manabu Abe, Fumihiro Sugiyama, Satoru Takahashi, Kenji Sakimura, Yu Hayashi, Qinghua Liu, Kazuhiko Kume, Shigeharu Wakana, Joseph S. Takahashi, Masashi Yanagisawa. (*Equally contributed) Forward-genetics analysis of sleep in randomly mutagenized mice. Nature 539, 378–383 (2016).

*Yu Hayashi, Mitsuaki Kashiwagi, Kosuke Yasuda, Reiko Ando, Mika Kanuka, Kazuya Sakai, *Shigeyoshi Itohara. (*Corresponding authors) Cells of a common developmental origin regulate REM/non-REM sleep and wakefulness in mice. Science 350, 957-961 (2015).

*Yu Hayashi, #Takaaki Hirotsu, #Ryo Iwata, Eriko Kage-Nakadai, Hirofumi Kunitomo, Takeshi Ishihara, Yuichi Iino, Takeo Kubo. (*Corresponding author, #Equally contributed) A trophic role for Wnt-Ror kinase signaling during developmental pruning in Caenorhabditis elegans. Nature Neuroscience 12, 981-987 (2009).

03 Education/Academic background and major awards

Education/Academic background

2003 B.S. Department of Biological Sciences, School of Science, University of Tokyo
2008 Ph.D. Department of Biological Sciences, Graduate School of Science, University of Tokyo
Special Postdoctoral Researcher, RIKEN Brain Science Institute (BSI)
2011 Researcher, RIKEN Brain Science Institute (BSI)
2013 Principal Investigator, Assistant Professor, International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba
2013-2017 (Concurrent position) JST PRESTO (Sakigake) Researcher
2016 Principal Investigator, Associate Professor, International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba


2019 The Frontier Salon Nagase Prize (Special Prize)
2017 The Young Scientists’ Prize, The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology (MEXT)
2016 The 26th Tsukuba Encouragement Prize


Why did you become a scientist?

To learn from nature

Nature has created lots of exciting phenomena and elaborate mechanisms that we humans could never have imagined. I hope to reveal such things and make good use of them for the public. Sleep is strongly linked to our everyday life and thus is an important topic both in terms of basic and applied science.

What are the characteristics of your lab?

Approaches using two animal species, mice and roundworms

Studies using two totally different animal species are ongoing, and discussions can often lead to unexpected ideas, allowing members to work with a wide perspective. In the course of evolution, the roundworm C. elegans acquired a very simple body plan by minimizing the number of cells. Thus, we expect that this simple model animal allows us to extract the most essential aspects of sleep. By contrast, mice are an ideal model animal for studying REM sleep, which is a state of many mysteries.

What are you most interested in lately

Capturing and observing wild animals

I often go to the brooks and woods to catch and observe wild animals such as insects, fish, amphibians and reptiles. I like to think this and that about the sleep in each animal.