Revealing the Role of Postnatal Theta Rhythm in Establishing Memory Consolidation Mechanism during REM Sleep
| Project/Area Number |
21K06419
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 46030:Function of nervous system-related
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| Research Institution | University of Tsukuba |
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Principal Investigator |
Kumar Deependra 筑波大学, 国際統合睡眠医科学研究機構, 研究員 (20747696)
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| Co-Investigator(Kenkyū-buntansha) |
船戸 弘正 筑波大学, 国際統合睡眠医科学研究機構, 客員教授 (90363118)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2023: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2022: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2021: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | Sleep / memory / Theta / hippocampus / neonates / TRAP2 / Dreamless / Fear expression / Neonatal sleep / Neonatal memory / Theta rhythm maturation / Dreamless mice / Engram |
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| Outline of Research at the Start |
During the development, a low amplitude theta wave starts appearing from postnatal day 16 (P16) and reaches its maturity on P26. However, the critical period when theta activity associated with REM sleep to consolidate memory is unknown. Therefore, this study aims to determine the normal development of REM theta-dependent memory consolidation mechanism during the neonatal stage.
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| Outline of Annual Research Achievements |
We found dreamless mice display low freezing behavior during fear conditioning, which could be due to chronic loss of REM sleep. Early data indicates their REM sleep duration gets further shortened during the postconditioning sleep, which can influence the memory consolidation. Furthermore, hippocampal theta shows low spectral power during REM sleep, that required for memory storage.
Indeed dreamless show low-freezing behavior one day or two weeks later. Dreamless shows a larger loss of memory at two weeks time, indicating faster memory decay compared with wild type littermates . Upon remote memory retrieval, the number of c-fos positive cells in the anterior cingulate cortex (ACC), a center for remote memory storage, was low in dreamless, which agrees with lower freezing behavior.
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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
Customized tetrode required to measure LFP in the neonatal brain is established.
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| Strategy for Future Research Activity |
In mutant mice, LFP will be measured simultaneously from the medial septum (theta generator) and hippocampus (prominent theta in REM) to narrow the region and cause-related with low theta in mutant mice.
Theta synchronicity between the hippocampus, amygdala, and medial prefrontal cortex is essential for memory task performance. LFP will be measured during fear learning, sleep, and memory retrieval period.
Can theta wave enhancement rescue fear memory in mutant mice? To test, dreamless mutants expressing channelrhodopsin in medial septum cholinergic neurons will receive laser light to induce hippocampal theta during task performance and sleep artificially.
How does theta enhancement affect the activity of learning tag cells? Imaging and optogenetics techniques will be combined to understand theta's role in the consolidation mechanism.
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Report
(2 results)
Research Products
(3 results)
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[Presentation] Learning and memory deficit in adult dreamless mice2022
Author(s)
Deependra Kumar, Tomoyuki Fujiyama, Takeshi Kanda, Chika Miyoshi, Miyo Kakizaki, Masanori Sakaguchi, Hiromasa Funato, Masashi Yanagisawa
Organizer
99th Annual Meeting of the Physiological Society of Japan-JST-CREST “Opt Bio” / WPI-IIIS Joint Symposium
Related Report
Int'l Joint Research
