Human masseter muscle: H- and tendon reflexes. Their paradoxical potentiation by muscle vibration.
We developed a method for direct electrical stimulation of the masseter nerve in man. Both direct M-reponses and genuine H-reflexes were recorded from the ipsilateral masseter muscle. Muscle vibration that inhibits the Achilles tendon reflex and the soleus H-reflex was found to potentiate the masseter tendon reflex and also the masseter H-reflex. This unexpected contrast may be related to peculiar brain stem circuitry of the masseter reflex mechanism.
D000125:Achilles Tendon / Q000502:physiology; D000328:Adult; D004558:Electric Stimulation; D005260:Female; D006181:H-Reflex; D006801:Humans; D008297:Male; D008410:Masticatory Muscles / Q000294:innervation / Q000502:physiology*; D012023:Reflex, Monosynaptic; D012026:Reflex, Stretch; D014276:Trigeminal Nerve / Q000502:physiology; D014732:Vibration