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Masseter muscle activity during vestibular stimulation in man
1Department of Biomedical Sciences, School of Medicine, University of Sassari, Italy.
Archives Italiennes De Biologie
|August 22, 2000
Summary
Static vestibular stimulation alters trigeminal motoneuron excitability, affecting masseter muscle activity asymmetrically. This study reveals likely macular vestibular input influences jaw muscle control.
Area of Science:
- Neuroscience
- Vestibular System
- Trigeminal System
Background:
- Vestibular afferents are known to influence trigeminal system activity.
- Understanding this interaction is crucial for comprehending head and jaw motor control.
Purpose of the Study:
- To investigate the effect of static vestibular stimulation on trigeminal motoneuron excitability in humans.
- To determine if head tilt influences masseter muscle activity and the exteroceptive silent period (ESP).
Main Methods:
- Ten healthy adults underwent static head tilt (20 degrees) while maintaining a fixed jaw posture.
- Masseter muscle electromyography (EMG) and exteroceptive silent period (ESP) duration and latency were recorded.
- Electrical stimulation of the inferior inter-incisal gum elicited the ESP.
Main Results:
- Static vestibular stimulation caused asymmetrical changes in voluntary masseter muscle activity.
- Muscle activity decreased during ipsilateral tilt and increased during contralateral tilt.
- The duration of both early (ESP1) and late (ESP2) silent periods was significantly altered by tilt direction.
Conclusions:
- Static vestibular stimulation, likely from macular otolith organs, exerts an asymmetrical influence on trigeminal motor activity.
- This suggests a direct role for the vestibular system in modulating jaw muscle control and posture.