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Functional organization of primate translational vestibulo-ocular reflexes and effects of unilateral labyrinthectomyTranslational vestibulo-ocular reflexes (trVORs) are characterized by distinct spatio-temporal properties and sensitivities that are proportional to the inverse of viewing distance. Anodal (inhibitory) labyrinthine stimulation (100 microA, < 2 s) during motion decreased the high-pass filtered dynamics, as well as horizontal trVOR sensitivity and its dependence on viewing distance. Cathodal (excitatory) currents had opposite effects. Translational VORs were also affected after unilateral labyrinthectomy. Animals lost their ability to modulate trVOR sensitivity as a function of viewing distance acutely after the lesion. These deficits partially recovered over time, albeit a significant reduction in trVOR sensitivity as a function of viewing distance remained in compensated animals. During fore-aft motion, the effects of unilateral labyrinthectomy were more dramatic. Both acute and compensated animals permanently lost their ability to modulate fore-aft trVOR responses as a function of target eccentricity. These results suggest that (1) the dynamics and viewing distance-dependent properties of the trVORs are very sensitive to changes in the resting firing rate of vestibular afferents and, consequently, vestibular nuclei neurons; (2) the most irregularly firing primary otolith afferents that are most sensitive to labyrinthine electrical stimulation might contribute to reflex dynamics and sensitivity; (3) inputs from both labyrinths are necessary for the generation of the translational VORs.
Document ID
20040141926
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Angelaki, D. E.
(University of Mississippi Medical Center Jackson 39216-4505, United States)
McHenry, M. Q.
Newlands, S. D.
Dickman, J. D.
Date Acquired
August 22, 2013
Publication Date
May 28, 1999
Publication Information
Publication: Annals of the New York Academy of Sciences
Volume: 871
ISSN: 0077-8923
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: EY10851
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Neuroscience

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