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Phasic motor activity reduction occurring with horizontal rapid eye movements during active sleep in human
J Kohyama1, M Shimohira, T Hasegawa
1Department of Pediatrics, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Experimental Brain Research
|January 1, 1995
Summary
Active sleep in children shows a phasic reduction in muscle activity linked to rapid eye movements (REMs). This motor inhibition, observed even in brain-damaged patients, suggests a brainstem origin for REM-related muscle control.
Area of Science:
- Neuroscience
- Sleep Medicine
- Developmental Pediatrics
Background:
- Active sleep is characterized by rapid eye movements (REMs) and distinct physiological patterns.
- Phasic muscle activity changes during REM sleep are crucial for understanding sleep regulation.
- Previous research in animals suggests brainstem mechanisms control muscle atonia during REM sleep.
Purpose of the Study:
- To investigate the phasic reduction of motor activity associated with REMs during active sleep in children.
- To determine the origin and characteristics of REM-related muscle inhibition in humans.
- To explore the relationship between REM sleep phenomena and motor control in both healthy children and those with brain damage.
Main Methods:
- Electromyography (EMG) was used to measure intercostal and mentalis muscle activity in 15 children (12 healthy, 3 with severe brain damage).
- Averaging techniques were applied to analyze muscle activity in relation to REM onset and mentalis muscle twitches.
- Latency and duration of muscle activity changes were calculated for healthy subjects.
Main Results:
- A significant decrease in intercostal muscle activity was observed following REM onset in healthy children (mean latency 37.1 ms, duration 225.9 ms).
- This REM-related muscle inhibition was also present in children with severe brain damage, supporting a brainstem origin.
- A REM-related reduction in mentalis muscle activity occurred before REM onset (mean onset 59.1 ms prior, duration 230.2 ms), alongside a twitch-related decrease in REM activity.
Conclusions:
- Phasic motor inhibition occurs during REM sleep in humans, consistent with findings in animal models.
- The observed muscle activity patterns suggest a brainstem generator controlling REMs, motor inhibition, and excitation (including twitches) during active sleep.
- These findings contribute to understanding the neural control of sleep and motor behavior in children, including those with neurological impairments.