Experimental Brain Research

, Volume 220, Issue 2, pp 101–108

Low-frequency physiological activation of the vestibular utricle causes biphasic modulation of skin sympathetic nerve activity in humans

  • Tarandeep Grewal
  • Tye Dawood
  • Elie Hammam
  • Kenny Kwok
  • Vaughan G. Macefield
Research Article

DOI: 10.1007/s00221-012-3118-4

Cite this article as:
Grewal, T., Dawood, T., Hammam, E. et al. Exp Brain Res (2012) 220: 101. doi:10.1007/s00221-012-3118-4

Abstract

We have previously shown that sinusoidal galvanic vestibular stimulation, a means of selectively modulating vestibular afferent activity, can cause partial entrainment of sympathetic outflow to muscle and skin in human subjects. However, it influences the firing of afferents from the entire vestibular apparatus, including the semicircular canals. Here, we tested the hypothesis that selective stimulation of one set of otolithic organs—those located in the utricle, which are sensitive to displacement in the horizontal axis—could entrain sympathetic nerve activity. Skin sympathetic nerve activity (SSNA) was recorded via tungsten microelectrodes inserted into cutaneous fascicles of the common peroneal nerve in 10 awake subjects, seated (head vertical, eyes closed) on a motorised platform. Slow sinusoidal accelerations–decelerations (~4 mG) were applied in the X (antero-posterior) or Y (medio-lateral) direction at 0.08 Hz; composite movements in both directions were also applied. Subjects either reported feeling a vague sense of movement (with no sense of direction) or no movement at all. Nevertheless, cross-correlation analysis revealed a marked entrainment of SSNA for all types of movements: vestibular modulation was 97 ± 3 % for movements in the X axis and 91 ± 5 % for displacements in the Y axis. For each sinusoidal cycle, there were two major peaks of modulation—one associated with acceleration as the platform moved forward or to the side, and one associated with acceleration in the opposite direction. We interpret these observations as reflecting inertial displacement of the stereocilia within the utricle during acceleration, which causes a robust vestibulosympathetic reflex.

Keywords

Sympathetic Vestibular Utricle Skin sympathetic nerve activity 

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Tarandeep Grewal
    • 1
  • Tye Dawood
    • 1
  • Elie Hammam
    • 1
  • Kenny Kwok
    • 2
  • Vaughan G. Macefield
    • 1
    • 3
  1. 1.School of MedicineUniversity of Western SydneyPenrithAustralia
  2. 2.Institute for Infrastructure EngineeringUniversity of Western SydneySydneyAustralia
  3. 3.Neuroscience Research AustraliaSydneyAustralia

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