1994 Fiscal Year Final Research Report Summary
Physiological Analysis of Correlation Between Rhythmical Jaw Movements and Monosynaptic Spinal Reflex in Humans
| Project/Area Number |
05454528
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
補綴理工系歯学
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| Research Institution | TOKYO MEDICAL AND DENTAL UNIVERSITY |
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Principal Investigator |
OHYAMA Takashi Tokyo Med.& Dent.Univ., Fac.of Dent., Professor, 歯学部, 教授 (50064366)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Yoshio Tokyo Med, & Dent.Univ., Fac.of Dent., Professor, 歯学部, 教授 (09557143)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Soleus / H-reflex / Rhythmical / Jaw movements / Gum chewing / Facilitation / Tonic |
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| Research Abstract |
We previously reported that human soleus H-reflex (S.H-R) was remarkably facilitated during teeth clenching, and that the magnitude of the facilitation increased with teeth clenching force. In this study, we investigated whether there was any modulation of S.H-R during rhythmical jaw movements with no teeth contacts (RJMs) and rhythmical gum chewing (RGC) . Experiments were carried out in 5 male volunteers (age : 22-27 years) with no stomatognathic dysfunction. The subjects were seated in a reclining armchair. Both legs were fixed with the knee and ankle joints at approximately 120ﾟ and 100ﾟ, respectively. Surface EMG was simultaneously recorded from the right soleus musle as well as the masseter and the anterior digastric muscles bilaterally. Electrical stimulation was applied to the tibial nerve at the popliteal fossa to elicit S.H-R. The subject performed self-paced RJMs and RGC.The peak-to-peak amplitude of the S.H-R during jaw movements was compared with that during maintaining the jaw at rest position. We found that (1) S.H-R was facilitated during RJMs and RGC (P<0.05, t-test) , and (2) there was no significant difference in the magnitude of the facilitation between the phase when the masseter muscle was active and that when the anterior digastric muscle was active (P>0.05, ANOVA) . It was concluded that (1) human soleus monosynaptic reflex is tonically facilitated during mastication, and (2) afferent impulses from intraoral mechanoreceptors are not indispensable for the facilitation. It is assumed that the oral motor activity exerts a strong influence on the bodily motor function in general.
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