Related Experiment Videos
[Modulation of soleus H-reflex by teeth clenching]
1Department for Stomatognathic Dysfunction, Faculty of Dentistry, Tokyo Medical and Dental University.
Summary
Voluntary teeth clenching significantly enhances the soleus H-reflex (Sol. H-R), indicating a strong link between jaw and body motor functions. This facilitation is linked to clenching force and descending brain influences.
Area of Science:
- Neuroscience
- Motor Control
- Human Physiology
Context:
- Investigating the neural pathways connecting jaw and limb motor systems.
- Understanding the influence of oral motor activity on general bodily motor function.
- Examining the human soleus H-reflex (Sol. H-R) modulation during voluntary tasks.
Purpose:
- To explore the correlation between voluntary teeth clenching and the modulation of the soleus H-reflex.
- To determine the relationship between masseter muscle activity and Sol. H-R facilitation.
- To elucidate the descending and afferent influences on Sol. H-R excitability during teeth clenching.
Summary:
- Voluntary teeth clenching markedly elevates soleus H-reflex (Sol. H-R) excitability, exceeding facilitation seen with other maximal voluntary efforts like hand clenching or the Jendrassik maneuver.
- Sol. H-R facilitation demonstrated a positive correlation with masseter electromyographic (EMG) activity and teeth clenching force.
- Facilitation onset preceded masseter EMG, peaking post-onset, and was partially reduced by inhibiting masseter EMG via lower lip stimulation, suggesting both central and peripheral neural contributions.
Impact:
- Provides evidence for a significant influence of oral motor activity on general bodily motor function.
- Highlights the interconnectedness of jaw and lower limb motor control systems.
- Suggests that descending pathways from higher brain centers and afferent input from oral structures contribute to enhanced Sol. H-R excitability during teeth clenching.