A utricular origin of frequency tuning to low-frequency vibration in the human vestibular system?

• Published in: Neuroscience letters 2009-02, Vol.451 (3), p.175-180
• Main Authors: Todd, Neil P.M., Rosengren, Sally M., Colebatch, James G.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; Afferent Pathways - physiology; Aged; Biological and medical sciences; Brain Stem - physiology; Cranial Nerves - anatomy & histology; Cranial Nerves - physiology; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Evoked Potentials - physiology; Female; Frequency dependence; Fundamental and applied biological sciences. Psychology; Hearing - physiology; Humans; Male; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Neck Muscles - innervation; Neck Muscles - physiology; Oculomotor Muscles - innervation; Oculomotor Muscles - physiology; Otolith; Physical Stimulation; Pitch Discrimination - physiology; Reflex, Vestibulo-Ocular - physiology; Saccule; Saccule and Utricle - anatomy & histology; Saccule and Utricle - physiology; Sound; Tuning; Utricule; Vertebrates: nervous system and sense organs; Vestibular Nerve - physiology; Vibration
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2008.12.055

Recent work has demonstrated that the human vestibular system displays a remarkable sensitivity to low-frequency vibration. To address the origin of this sensitivity we compared the frequency response properties of vestibular reflexes to 10 ms bursts of air-conducted sound and transmastoid vibration, which are thought to be differentially selective for the saccule and utricle, respectively. Measurements were made using two separate central pathways: vestibular evoked myogenic potentials (VEMPs), which are a manifestation of vestibulo-collic projections, and ocular vestibular evoked myogenic potentials (OVEMPs), which are a manifestation of vestibulo-ocular projections. For both response pathways air-conducted sound and vibration stimuli produced the same patterns of quite different tuning. Sound was characterised by a band-pass tuning with best frequency between 400 and 800 Hz whereas vibration showed a low-pass type response with a largest response at 100 Hz. Our results suggest that the tuning is at least in part due to properties of end-organs themselves, while the 100 Hz best frequency may be a specifically utricular feature.