Plugging of reciprocal semicircular canal pairs eliminates the response associated with rotation about their associated axis at a frequency of 0.2 Hz. At higher frequencies, there is a Anormalization of the spatial responses of the angular vestibulo-ocular reflex (aVOR). The hypothesis of this study is that this normalization occurs because plugging does not eliminate the respons of the plugged canal. Rather, it modifies the canal dynamics so that the dominant time constant of the canal is lowered. At present, there is no direct evidence that plugged canal afferents respond to rotation at higher frequencies. Neither has central vestibular activity been studied following canal plugging to determine if indeed there is spatial adaptation. The purpose work will address the following questions: Does canal plugging modify the spatial and temporal characteristics of the afferents in response to rotation? How will the spatial characteristics of central vestibular neurons be affected by plugging of the lateral canals and by section of the lateral canal nerves? Vestibular afferents of the cynomolgus monkeys will be recorded before and after bilateral lateral canal plugging. It is expected that the amplitude of modulation of lateral-canal afferents will be approximately zero at 0.2 Hz after plugging, but will tend to Anormalize as the head oscillation frequency is increased up to 4.0 Hz. Vertical canal afferents should maintain their normal frequency characteristics. Spatial oculomotor and central vestibular neuronal responses will be compared following bilateral sectioning of the nerves and after canal plugging to determine whether there is significant spatial adaptation following nerve cut. It is expected that the spatial responses will be altered due to central adaptation, but that changes in spatial responses as a function of frequency will not be as significant as for canal plugging. This work should lead to a clearer understanding of how lesions, such as plugging and nerve section, affect the sensory processing of head movements and how the central vestibular system adapts to these types of lesions.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29DC003787-01
Application #
2670090
Study Section
Hearing Research Study Section (HAR)
Project Start
1998-07-01
Project End
2003-06-30
Budget Start
1998-07-01
Budget End
1999-06-30
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Neurology
Type
Schools of Medicine
DUNS #
114400633
City
New York
State
NY
Country
United States
Zip Code
10029
Yakushin, Sergei B; Raphan, Theodore; Buttner-Ennever, Jean A et al. (2005) Spatial properties of central vestibular neurons of monkeys after bilateral lateral canal nerve section. J Neurophysiol 94:3860-71
Yakushin, Sergei B; Raphan, Theodore; Cohen, Bernard (2003) Gravity-specific adaptation of the angular vestibuloocular reflex: dependence on head orientation with regard to gravity. J Neurophysiol 89:571-86
Yakushin, Sergei B; Bukharina, Svetlana E; Raphan, Theodore et al. (2003) Adaptive changes in the angular VOR: duration of gain changes and lack of effect of nodulo-uvulectomy. Ann N Y Acad Sci 1004:78-93
Yakushin, Sergei B; Palla, Antonella; Haslwanter, Thomas et al. (2003) Dependence of adaptation of the human vertical angular vestibulo-ocular reflex on gravity. Exp Brain Res 152:137-42
Arai, Yasuko; Yakushin, Sergei B; Dai, Mingjia et al. (2002) Spatial orientation of caloric nystagmus. Ann N Y Acad Sci 956:190-204
Cohen, Bernard; John, Padmore; Yakushin, Sergei B et al. (2002) The nodulus and uvula: source of cerebellar control of spatial orientation of the angular vestibulo-ocular reflex. Ann N Y Acad Sci 978:28-45
Kushiro, Keisuke; Dai, Mingjia; Kunin, Mikhail et al. (2002) Compensatory and orienting eye movements induced by off-vertical axis rotation (OVAR) in monkeys. J Neurophysiol 88:2445-62
Arai, Yasuko; Yakushin, Sergei B; Cohen, Bernard et al. (2002) Spatial orientation of caloric nystagmus in semicircular canal-plugged monkeys. J Neurophysiol 88:914-28
Yakushin, S B; Dai, M; Raphan, T et al. (2001) Changes in the vestibulo-ocular reflex after plugging of the semicircular canals. Ann N Y Acad Sci 942:287-99
Yakushin, S B; Raphan, T; Cohen, B (2000) Context-specific adaptation of the vertical vestibuloocular reflex with regard to gravity. J Neurophysiol 84:3067-71

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