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The EMG development of the longissimus and multifidus muscles after plugging the horizontal semicircular canals
1h.c.geisler@med.rug.nl
Insights
Vestibular system development is crucial for motor skills. Plugging horizontal semicircular canals in young rats delayed back muscle coordination during locomotion, impacting dynamic postural development.
Area of Science:
- Neuroscience
- Developmental Biology
- Motor Control
Background:
- The vestibular system, particularly horizontal semicircular canals, plays a key role in balance and spatial orientation.
- Understanding the developmental impact of vestibular input on motor behavior is essential for comprehending sensorimotor integration.
Purpose of the Study:
- To investigate the effects of early-life vestibular deprivation on the development of electromyographic (EMG) activity in rat back muscles.
- To analyze the relationship between EMG activity and locomotor behavior following horizontal semicircular canal plugging.
Main Methods:
- Horizontal semicircular canals were plugged in rats on postnatal day 5 (P5).
- EMG activity of the M. longissimus lateralis and M. multifidus was recorded and analyzed in relation to locomotion, grooming, and rearing from P5 to P46.
- Locomotor behavior was a primary focus for analysis.
Main Results:
- Vestibular deprivation retarded the development of temporal coupling between M. longissimus lateralis EMG bursts and hind paw swing phase by approximately 3 days.
- The coupling of maximal M. longissimus lateralis activity to the hind paw swing phase showed even greater retardation.
- No significant differences in M. multifidus EMG development were observed between normal and vestibularly deprived rats.
Conclusions:
- Horizontal semicircular canal input is vital for the dynamic postural and general motor development.
- The absence of vestibular information affects the fine-tuning of back muscle activity during locomotion up to at least postnatal day 40.
Abstract:
The effects of plugging both horizontal semicircular canals at the 5th postnatal day (P5) on the development of the EMG of two back muscles (the M. longissimus lateralis and the M. multifidus) were studied in rats between P5 and P46. The EMG was related to locomotion, grooming, and rearing of these rats. Special attention was paid to locomotor behavior. After this vestibular deprivation, the development of a consistent temporal relation between burst activity in the EMG of both Mm. longissimii laterales and the swing phase of one hind paw was retarded by about 3 days. The development of coupling of maximal activity in the M. longissimus lateralis to the swing phase of one of the hind paws was even more retarded. No differences were observed between normal and vestibularly deprived rats during the development of activity in the Mm. multifidi. Our results indicate that information from the horizontal semicircular canals is essential for dynamic postural development and probably, therefore, for motor development in general. Furthermore, lack of such information has effects on the fine tuning of back muscle activity during locomotion at least until P40.