1990 Fiscal Year Final Research Report Summary
Ontogeny of Rem Sleep, Nrem Sleep and Awake State in the Human Fetus in Utero
| Project/Area Number |
63480369
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Obstetrics and gynecology
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| Research Institution | Kyushu University |
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Principal Investigator |
NAKANO Hitoo Faculty of Medicine, Kyushu University Professor, 医学部, 教授 (40038766)
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| Co-Investigator(Kenkyū-buntansha) |
HORIMOTO Naoki Faculty of Medicine, Kyushu University Resident, 医学部, 医員
SATOH Shoji Faculty of Medicine, Kyushu University Assistant, 医学部, 助手 (00225947)
INOUE Mitsuru Social Insurance Saga Hospital Chief, 医長
KOYANAGI Takashi Faculty of Medicine, Kyushu University Associate Professor, 医学部, 助教授 (30136452)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Human fetus / Ontogeny / Rem sleep / Nrem sleep / Awake state / Real-time ultrasound |
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| Research Abstract |
For the past 3 years, we have continued to make studies on ontogeny of behavioral patterns in the human fetus in utero, observed using a real-time ultrasound, in relation to the development of brain function.
Consequently, the following findings were obtained :
1. Fetal eye movement became observable at around 16 weeks of gestation with sporadic onset of occurrence. At 24-25 weeks of gestation onwards, the eye movement was found to gradually consolidate, thereby leading to formation of eye-movement (REM) and non eye-movement (NREM) periods. At the latest by 37-38 weeks of gestation, REM and NREM periods revealed an alternative change with almost uniform duration : 24 (mean value) and 22 minutes, respectively.
2. When attempting to analyze the duration of the individual eye movement as a parameter by means of piecewise regression, the critical given duration point was noted, with statistical significance, at 0.6-0.7 second in the fetuses at 33 weeks of gestation or more. This finding demonstrates that there are two different types of eye movement : rapid and slow eye movements, thereby revealing the in utero existence of REM sleep state.
3. Random mouthing movements occurring at a wide range of interval between 300 and 525 milliseconds were observed during REM sleep and were unrelated to advance in gestation, while regular mouthing every 300 to 600 milliseconds concurred only with NREM period at 35 weeks of gestation thereafter. This provides the evidence that there exists NREM sleep state in the human fetus.
4. From study on relation between mydriasis/miosis and REM/NREM periods, it was evident that about 5% of examination period in the fetuses at 36-40 weeks of gestation was observed to show the special period with mydriasis occurring during REM period. Therefore, this finding strongly suggests a sprout of awake state beginning during intrauterine life.
We believe our results will take a step toward human fetal ethology.
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