Labyrinthine projection to the hypoglossal nucleus.
Evoked potentials and responses of single hypoglossal neurons were recorded in response to electrical stimulation of the labyrinth. In addition, the spontaneous electrical activity of hypoglossal neurons was significantly modified in response to ipsi- and contralateral static tilt of the whole animal and thermic stimulation of the labyrinth. The experiment showed that the labyrinth modulates the electrical activity of hypoglossal neurons with phasic inputs in response to ampullar stimulation and with tonic inputs in response to macular stimulation. The vestibular phasic influence of hypoglossal neurons represents the most adequate functional pattern to obtain a quick, short lasting response of the tongue muscles instantly modifiable with every abrupt head displacement. On the contrary, the vestibular tonic influence of hypoglossal neurons represents the most adequate functional pattern to obtain not only adjustment but also maintenance of the muscular lingual response to static displacement of the head.
Mameli
O
O
Institute of Human Physiology, School of Medicine, University of Sassari, Italy.
Tolu
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E
Melis
F
F
Caria
M A
MA
D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology; D007758:Ear, Inner / Q000502:physiology*; D004558:Electric Stimulation; D005071:Evoked Potentials; D006358:Hot Temperature; D007002:Hypoglossal Nerve / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D011817:Rabbits