• T Koyanagi.
• Maternity and Perinatal Care Unit, Kyushu University Hospital, Fukuoka.
• Nippon Sanka Fujinka Gakkai Zasshi. 1991 Aug 1;43(8):843-52.

AbstractBehavior is considered a one to one match between the manifestation of a particular individual motor activity (movement) and its correlated brain function. Each motor activity can be seen to run on its own developmental course with advance in gestation, while various movements also develop in concurrence with one another during intrauterine life, gradually integrating into complex and accommodated movements. I emphasized the present study, under real-time ultrasound observation, for investigating whether or not three states: REM (rapid eye movement) sleep, NREM (non-rapid eye movement) sleep and the waking state actually exist in utero, and if so, when the development of these states begins. 1. Examined for 30-40 minutes were 21 fetuses, including 10 from 33 to 36 weeks of gestation and 11 from 37 to 41 weeks of gestation. As parameters, the duration of each eye movement unit and the cumulative duration of this movement, from the shortest to a given duration, per individual case, were observed. A scattergram of cumulative duration vs, given duration obtained from all cases, for each age-group, were analyzed using "piecewise linear regression". Critical points were noted, with statistical significance, at 0.62 second for the earlier group and at 0.76 second for the later group. These findings reveal two different types of eye movement: rapid and slow eye movements. The fact that the rapid eye movement coexists with the slow eye movement during REM period indicates that REM sleep exists in utero at the latest at 33 weeks of gestation. 2. Observed for 60 minutes were 26 fetuses from 28 to 41 weeks of gestation. Regular mouthing movement every 300 to 600 msec concurred significantly only with the NREM period from 35 weeks of gestation onwards. Random mouthing movements were observed predominantly during REM sleep and were unrelated to the advance in gestational age. This concurrence between the NREM period and regular mouthing indicates the existence of NREM sleep in utero at this age of gestation. 3. To evaluate whether the waking state is present, 10 fetuses at 36 weeks or more of gestation were examined for a concurrence between miosis/mydriasis and the REM/NREM periods. Using pupil diameter as a parameter, miosis and mydriasis were distinguished from each other, statistically, by means of "least median of squares regression". Accordingly, the NREM period was occupied only by miosis (41.0% of total observation period), while the REM period was divided into two conditions: 52.6% with miosis and 6.4% with mydriasis.(ABSTRACT TRUNCATED AT 400 WORDS)

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