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

Shinichi Miyazaki, Taizo Kawano, Masashi Yanagisawa, Yu Hayashi. Intracellular Ca2+ dynamics in the ALA neuron reflect sleep pressure and regulate sleep in Caenorhabditis elegans. iScience DOI:10.1016/j.isci.2022.104452 (2022)

Chia-Jung Tsai, Takeshi Nagata, Chih-Yao Liu, Takaya Suganuma, Takeshi Kanda, Takehiro Miyazaki, Kai Liu, Tsuyoshi Saitoh, Hiroshi Nagase, Michael Lazarus, Kaspar Vogt, Masashi Yanagisawa, Yu Hayashi. Cerebral capillary blood flow upsurge during REM sleep is mediated by A2A receptors. Cell Reports 17:109558 (2021).

Ayaka Nakai, Tomoyuki Fujiyama, Nanae Nagata, Mitsuaki Kashiwagi, Aya Ikkyu, Marina Takagi, Chika Tatsuzawa, Kaeko Tanaka, Miyo Kakizaki, Mika Kanuka, Taizo Kawano, Seiya Mizuno, Fumihiro Sugiyama, Satoru Takahashi, Hiromasa Funato, Takeshi Sakurai, Masashi Yanagisawa, Yu Hayashi. Sleep Architecture in Mice Is Shaped by the Transcription Factor AP-2β. Genetics 216:753-764 (2020).

Mitsuaki Kashiwagi, Mika Kanuka, Chika Tatsuzawa, Hitomi Suzuki, Miho Morita, Kaeko Tanaka, Taizo Kawano, Jay W Shin, Harukazu Suzuki, Shigeyoshi Itohara, Masashi Yanagisawa, Yu Hayashi. Widely Distributed Neurotensinergic Neurons in the Brainstem Regulate NREM Sleep in Mice. Current Biology 30:1002 (2020).

Sakura Eri B. Maezono (*Co-first author), Mika Kanuka (*Co-first author), Chika Tatsuzawa, Miho Morita, Taizo Kawano, Mitsuaki Kashiwagi, Pimpimon Nondhalee, Masanori Sakaguchi, Takashi Saito, Takaomi C. Saido, Yu Hayashi. Progressive changes in sleep and its relations to amyloid-β distribution and learning in single App knock-in mice. eNeuro 7(2) ENEURO.0093-20.2020 1–14 (2020).

Shinnosuke Yasugaki, Chih-Yao Liu, Mitsuaki Kashiwagi, Mika Kanuka, Takato Honda, Shingo Miyata, Masashi Yanagisawa, Yu Hayashi. Effects of 3 Weeks of Water Immersion and Restraint Stress on Sleep in Mice. Frontiers in Neuroscience 13:1072 (2019).

*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).

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
2016-2020 Principal Investigator, Associate Professor, International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba
2020-2022 Professor, Department of Human Health Sciences, Graduate School of Medicine, Kyoto University
2020-present (Concurrent Position) Visiting professor (WPI-IIIS) and Principal Investigator,International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba
2022-present (Concurrent Position) Specific Professor, Department of Human Health Sciences, Graduate School of Medicine, Kyoto University
2022-present Professor, Department of Biological Sciences, Graduate School of Science, The University of Tokyo


2020 US NAM (National Academy of Medicine) Catalyst Award
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.