Inactivation of semicircular canals causes adaptive increases in otolith-driven tilt responses

J Neurophysiol. 2002 Mar;87(3):1635-40. doi: 10.1152/jn.00775.2001.

Abstract

Growing experimental and theoretical evidence suggests a functional synergy in the processing of otolith and semicircular canal signals for the generation of the vestibulo-ocular reflexes (VORs). In this study we have further tested this functional interaction by quantifying the adaptive changes in the otolith-ocular system during both rotational and translational movements after surgical inactivation of the semicircular canals. For 0.1-0.5 Hz (stimuli for which there is no recovery of responses from the plugged canals), pitch and roll VOR gains recovered during earth-horizontal (but not earth-vertical) axis rotations. Corresponding changes were also observed in eye movements elicited by translational motion (0.1-5 Hz). Specifically, torsional eye movements increased during lateral motion, whereas vertical eye movements increased during fore-aft motion. The findings indicate that otolith signals can be adapted according to a compromised strategy that leads to improved gaze stabilization during motion. Because canal-plugged animals permanently lose the ability to discriminate gravitoinertial accelerations, adapted animals can use the presence of gravity through otolith-driven tilt responses to assist gaze stabilization during earth-horizontal axis rotations.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptation, Physiological / physiology*
  • Animals
  • Eye Movements / physiology
  • Gravity Sensing / physiology
  • Macaca mulatta
  • Otolithic Membrane / physiology*
  • Reflex, Vestibulo-Ocular / physiology
  • Rotation
  • Semicircular Canals / physiology*
  • Space Perception / physiology
  • Torsion Abnormality