Head roll dependent variability of subjective visual vertical and ocular counterroll

Exp Brain Res. 2009 Jun;195(4):621-6. doi: 10.1007/s00221-009-1823-4. Epub 2009 May 5.

Abstract

We compared the variability of the subjective visual vertical (SVV) and static ocular counterroll (OCR), and hypothesized a correlation between the measurements because of their shared macular input. SVV and OCR were measured simultaneously in various whole-body roll positions [upright, 45 degrees right-ear down (RED), and 75 degrees RED] in six subjects. Gains of OCR were -0.18 (45 degrees RED) and -0.12 (75 degrees RED), whereas gains of compensation for body roll in the SVV task were -1.11 (45 degrees RED) and -0.96 (75 degrees RED). Normalized SVV and OCR variabilities were not significantly different (P > 0.05), i.e., both increased with increasing roll. Moreover, a significant correlation (R(2) = 0.80, slope = 0.29) between SVV and OCR variabilities was found. Whereas the gain of OCR is different from the gain of SVV, trial-to-trial variability of OCR follows the same roll-dependent modulation observed in SVV variability. We propose that the similarities in variability reflect a common otolith input, which, however, is subject to distinct central processing for determining the gain of SVV and OCR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Eye Movements / physiology*
  • Female
  • Gravity Sensing / physiology
  • Head Movements / physiology*
  • Humans
  • Judgment / physiology
  • Male
  • Orientation / physiology*
  • Otolithic Membrane / physiology
  • Photic Stimulation
  • Psychomotor Performance / physiology*
  • Reflex, Vestibulo-Ocular / physiology*
  • Saccule and Utricle / physiology
  • Space Perception / physiology
  • Vestibule, Labyrinth / physiology*