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: 94/4/2653    most recent 00739.2004v1 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 PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Stewart, C. M. Articles by Perachio, A. A. Search for Related Content PubMed PubMed Citation Articles by Stewart, C. M. Articles by Perachio, A. A.

Visual-Vestibular Interactions During Vestibular Compensation: Role of the Pretectal NOT in Horizontal VOR Recovery After Hemilabyrinthectomy in Rhesus Monkey

¹Departments of Otolaryngology and ² Neuroscience, University of Texas Medical Branch, Galveston, Texas; and ³Yerkes National Primate Research Center and ⁴Department of Neurology, Emory University, Atlanta, Georgia

Submitted 21 July 2004; accepted in final form 19 February 2005

Damage to the vestibular labyrinth leads to profound nystagmus and vertigo. Over time, the vestibular-ocular system recovers in a process called vestibular compensation leading to reduced nystagmus and vertigo provided visual signals are available. Our study was directed at identifying sources of visual information that could play a role in vestibular compensation. Specifically, we investigated the role of the pretectal nucleus of the optic tract (NOT) in vestibular compensation after hemilabyrinthectomy (HL) in rhesus monkeys. We chose the NOT because this structure provides critical visual motion information for adaptive modification of the vestibular ocular reflex (VOR). We produced bilateral NOT lesions by injecting the excitotoxin ibotenic acid. We compared vestibular compensation after HL in NOT-lesioned and control animals with intact NOTs. We measured eye movements with an electromagnetic method employing scleral search coils. Measurements included slow-phase eye velocity during spontaneous nystagmus, per- and postrotatory nystagmus and the horizontal VOR (hVOR) gain (eye-velocity/head velocity) associated with per- and postrotatory and sinusoidal (0.2–2.0 Hz; 30–90°/s) whole body oscillation around the earth-vertical axis. VOR gain was low (<0.5) for rotation toward the HL side. Our control animal evinced significant vestibular compensation with VOR gains approaching unity by 100 days post HL. In contrast, monkeys with bilateral lesions of the NOT never obtained this significant recovery with hVOR gains well below unity at 100 days and beyond. Therefore our studies demonstrate that the NOT is an essential source of visual signals for the process of vestibular compensation after HL.

This article has been cited by other articles:

				S. Ono and M. J. Mustari Horizontal Smooth Pursuit Adaptation in Macaques After Muscimol Inactivation of the Dorsolateral Pontine Nucleus (DLPN) J Neurophysiol, November 1, 2007; 98(5): 2918 - 2932. [Abstract] [Full Text] [PDF]