Researcher Information



Dreams: how and why they happen

Department of Biological Sciences, Behavioral Neurobiology


Investigating the neural mechanisms of dreaming and the physiological function of dreaming using genetically engineered mice

FieldNeuroscience, Sleep research
KeywordSleep, Rapid eye movement (REM) sleep, Dreams, Electroencephalogram (EEG), Ponto-geniculo-occipital (PGO) waves, Brain, Neuron, Memory, Genetically engineered mice, Electrophysiology, Optical imaging, Optogenetics, Programming

Introduction of Research

If we sleep eight hours a day, we spend as much as one-third of our lives sleeping. Why do we sleep? Why do we dream? Why do we have rapid eye movement (REM) and non-REM sleep? We are still unable to correctly answer such fundamental questions. In our laboratory, we perform research to answer these questions using genetically engineered mice (Photo 1). We aim to clarify the neural mechanisms and physiological functions of dreams, in particular. To this end, we are conducting research using various techniques, including large-scale extracellular recording (Photo 2), which can record a large number of neural activities at once; optical imaging (Photo 3), which records dynamics in intracellular ion concentrations; optogenetics (Photo 4), which controls neural activities through light illumination; and programming (Photo 5) to analyze the data.

1. Sleeping mice
2. COMS digital multi-electrode probe. On the needle-like tip, more than 1000 recording electrodes are mounted.
3. Macro-zoom microscope for optical imaging
4. Light-driven proteins (green) expressed in specific type of neurons (red)
5. Source code of programming

Representative Achievements

What are the neural mechanisms and physiological functions of dreams?
Tsunematsu T*
Neurosci Res. 2023, 189, 54-59.
Region-specific and state-dependent astrocyte Ca2+ dynamics during the sleep-wake cycle in mice.
Tsunematsu T*, Sakata S, Sanagi T, Tanaka KF, Matsui K
J Neurosci. 2021, 41(25): 5440-5452.
State-dependent brainstem ensemble dynamics and their interactions with hippocampus across sleep states.
Tsunematsu T, Patel AP, Onken A, Sakata S
eLife 2020, 9: e52244
Optogenetic manipulation of activity and temporally-controlled cell-specific ablation reveal a role for MCH neurons in sleep/wake regulation.
Tsunematsu T, Ueno T, Tabuchi S, Inutsuka A, Tanaka KF, Hasuwa H, Kilduff TS, Terao A, Yamanaka A
J Neurosci. 2014, 34(20): 6896-6909.
Acute optogenetic silencing of orexin/hypocretin neurons induces slow-wave sleep in mice.
Tsunematsu T, Kilduff TS, Boyden ES, Takahashi S, Tominaga M, Yamanaka A
J Neurosci. 2011, 31(29): 10529-10539.
Academic degreePh. D.
Self Introduction

I am from Tottori. My hobbies are sleeping, dreaming, driving, and bathing in hot springs. I am a groupie of Rika Ishikawa and Masaki Sato (Morning Musume. OG).

Academic background2006 B.S. College of Biological Science, Second Cluster of Colleges, University of Tsukuba
2008 M.P.A.S. Graduate School of Comprehensive Human Sciences, University of Tsukuba
2009 JSPS Research Fellowship (DC2), National Institute for Physiological Sciences
2011 Ph.D. Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI)
2011 JSPS Postdoctoral fellow, National Institute for Physiological Sciences
2013 JSPS Postdoctoral fellow, Nagoya University
2014 JSPS Postdoctoral Fellow for Research Abroad/Research Associate, University of Strathclyde (UK)
2017 Assistant Professor, Tohoku University
2018 PRESTO Researcher, JST
2023- Lecturer, Hokkaido University
Affiliated academic societyJapanese Society of Sleep Research, The Japan Neuroscience Society, Society for Neuroscience
ProjectFusion Oriented REsearch for disruptive Science and Technology
Room addressScience Building 5, 5-911