HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 97/6/4357    most recent 01338.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Macpherson, J. M. Articles by Ting, L. H. Search for Related Content PubMed PubMed Citation Articles by Macpherson, J. M. Articles by Ting, L. H.

Bilateral Vestibular Loss in Cats Leads to Active Destabilization of Balance During Pitch and Roll Rotations of the Support Surface

Neurological Sciences Institute, Oregon Health and Science University, Beaverton, Oregon

Submitted 19 December 2006; accepted in final form 9 April 2007

Although the balance difficulties accompanying vestibular loss are well known, the underlying cause remains unclear. We examined the role of vestibular inputs in the automatic postural response (APR) to pitch and roll rotations of the support surface in freely standing cats before and in the first week after bilateral labyrinthectomy. Support surface rotations accelerate the body center of mass toward the downhill side. The normal APR consists of inhibition in the extensors of the uphill limbs and excitation in the downhill limbs to decelerate the body and maintain the alignment of the limbs with respect to earth-vertical. After vestibular lesion, cats were unstable during rotation perturbations and actively pushed themselves downhill rather than uphill, using a postural response that was opposite to that seen in the control trials. The extensors of the uphill rather than downhill limbs were activated, whereas those of the downhill limbs were inhibited rather than being excited. We propose that vestibular inputs provide an important reference to earth-vertical, which is critical to computing the appropriate postural response during active orientation to the vertical. In the absence of this vestibular information, subjects orient to the support surface using proprioceptive inputs, which drives the body downhill resulting in instability and falling. This is consistent with current models of sensory integration for computation of body posture and orientation.

This article has been cited by other articles:

				D.A.E. Bolton and J. E. Misiaszek Contribution of Hindpaw Cutaneous Inputs to the Control of Lateral Stability During Walking in the Cat J Neurophysiol, September 1, 2009; 102(3): 1711 - 1724. [Abstract] [Full Text] [PDF]

				D. C. Dunbar, J. M. Macpherson, R. W. Simmons, and A. Zarcades Stabilization and mobility of the head, neck and trunk in horses during overground locomotion: comparisons with humans and other primates J. Exp. Biol., December 15, 2008; 211(24): 3889 - 3907. [Abstract] [Full Text] [PDF]