Related Experiment Video
Updated: Apr 26, 2026

Measuring Contralateral Silent Period Induced by Single-Pulse Transcranial Magnetic Stimulation to Investigate M1 Corticospinal Inhibition
Published on: August 23, 2022
Trigeminal-hypoglossal silent period: a pontomedullary brainstem reflex
1Department of Neurology, Asklepios Klinik Barmbek, Rübenkamp 220, 22291, Hamburg, Germany.
Introduction:
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.
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