title: Trigeminal-hypoglossal silent period: a pontomedullary brainstem reflex.
abstract: BACKGROUND
  Animal studies have shown inhibitory connections between the sensory trigeminal nucleus and hypoglossal nucleus. I investigated whether these inhibitory projections are present in humans.
  
  
  METHODS
  I examined 18 healthy subjects, 2 patients with brainstem stroke, and 5 patients with multiple sclerosis using a specially designed oral stimulation and recording device.
  
  
  RESULTS
  In 16 of 18 subjects, a bilateral suppression period of tongue muscle activity after unilateral electrical stimulation of the mucosal V2 afferents was observed. The silent period started at 31.1 (SD 4.7) ms (ipsilateral) and 32.0 (SD 4.9) ms (contralateral). The mean duration of the silent period was 31.4 (SD 10.2) ms (ispilateral) and 32.5 (SD 9.8) ms (contralateral). Patients with dorsolateral pontomedullary lesions had ipsilateral absence of the silent period.
  
  
  CONCLUSIONS
  This study confirms the existence of a bilateral trigeminal-hypoglossal silent period in humans.
authors: Department of Neurology, Asklepios Klinik Barmbek, Rübenkamp 220, 22291, Hamburg, Germany.
authors: Peter P
authors: PP
authors: Urban
mesh_terms: D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000502:physiology* / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000502:physiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000502:physiology* / Q000503:physiopathology; D012018:Reflex / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology; D014276:Trigeminal Nerve / Q000502:physiology* / Q000503:physiopathology
keywords: brainstem; brainstem reflex; hypoglossal nerve; inhibitory reflex; silent period; trigeminal nerve