Indexed on: 26 Jul '14Published on: 26 Jul '14Published in: Muscle & Nerve
Animal studies have shown inhibitory connections between the sensory trigeminal nucleus and hypoglossal nucleus. I investigated whether these inhibitory projections are present in humans.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.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.This study confirms the existence of a bilateral trigeminal-hypoglossal silent period in humans.