2019 Fiscal Year Annual Research Report
The role of the nucleus accumbens in regulating slow-wave sleep by motivated behavior
| Project/Area Number |
17H02215
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| Research Institution | University of Tsukuba |
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Principal Investigator |
ラザルス ミハエル 筑波大学, 国際統合睡眠医科学研究機構, 准教授 (80469650)
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| Co-Investigator(Kenkyū-buntansha) |
高田 陽子 筑波大学, 国際統合睡眠医科学研究機構, 研究員 (60435740)
斉藤 毅 筑波大学, 国際統合睡眠医科学研究機構, 助教 (80609933)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Keywords | Sleep / Motivation / Nucleus Accumbens |
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| Outline of Annual Research Achievements |
As humans, we often defy sleepiness and stay awake when attention is necessary, but also experience an inescapable desire to sleep in boring situations. The brain mechanisms governing the regulation of sleep by cognitive and emotional factors are not well understood. We reported that a part of the brain that is associated with motivation and pleasure - the nucleus accumbens (NAc)- also can produce sleep. The new findings may explain why we have the tendency to fall asleep in the absence of motivating stimuli, i.e., when bored. We used chemo-genetic and optical techniques to remotely control the activities of NAc neurons that express adenosine A2A receptors (A2AR), also known as indirect pathway neurons. As a result, we discovered that NAc A2AR neurons have an extremely strong ability to induce sleep that is indistinguishable from the major component of natural sleep, known as slow-wave sleep, as it is characterized by slow and high-voltage brain waves.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
We revealed a prominent role of NAc indirect pathway neurons in nucleus accumbens in sleep/wake regulation (Oishi et al., Nat Commun, 2017, 8:734) and proposed that this brain circuit may explain the tendency to fall asleep in the absence of motivating stimuli, i.e., when bored. Our paper received worldwide media attention which is reflected in a high Altmetric Score: 367. We also revealed that adenosine is a plausible candidate molecule for activating NAc core A2AR neurons to induce SWS because elevated adenosine levels in the NAc core promote SWS via A2AR (Zhou X, et al., Neurochem Int, 2019, 124:256). The project has been progressing well and so far, has exceeded our expectations.
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| Strategy for Future Research Activity |
We proposed for the final stage of the Kiban B project to investigate the role of glial cells surrounding NAc neurons for sleep control by blocking glutamate and adenosine release from glial cells.
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