This research program is studying the physiology of the ocular and neck reflexes that control gaze, and the specific role of the cerebellar nodulus and uvula in producing these reflexes. Gaze reflexes are necessary for clear vision because they steady the head and keep the eyes pointed in a constant direction as the head moves. Vision is poor and balance unstable without gaze reflexes. The cerebellum is critical to proper operation of gaze reflexes, but only the lateral vestibulocerebellum, or flocculus, has been extensively studied. The neural inputs and outputs of nodulus and uvula imply a vestibular function in gaze reflex control, yet most studies of cerebellar roles in gaze reflexes have neglected nodulus and uvula. Research during the firest three years of this research program has made important advances in describing properties of the gaze reflexes in which nodulus and uvula participate, documenting deficits in vestibulo-ocular and optokinetic gaze reflexes after nodulus-uvula lesions, and recording neuronal activity in nodulus and uvula. We will extend our findings in three areas and add a fourth area of emphasis. 1) We will continue to explore normal gaze reflexes, expanding our studies to include vestibulo-ocular responses to stimuli that especially excite nodulus-uvula neural activity. 2) We will further characterize simple spike responses of nodulus-uvula Purkinje cells, searching for properites that distinguish these cerebellar responses from other cerebellar response. We will also record nodulus-uvula neural activity during short term vestibular reflex adaptation procedures. 3) We will extend our studies of the effects of nodulus-uvula lesions on gaze reflexes and their adaptive capacity. 4) We will add recording and lesion studies that directly compare nodulus-uvula neural responses or lesions to those of cerebellar flocculus. This will test the hypothesis that nodulus and uvula participate primarily in ongoing gaze reflexes while flocculus functions primarily in adaptive control of gaze reflexes. The results of the proposed experiments will give us further insight into the functions of the cerebellum in motor behavior and the different roles of medial nodulus-uvula cerebellum and lateral cerebellar flocculus. We hope also for further insight into basic reflex functions, adaptation to disturbed sensory inputs, and recovery from neurological disorders caused by brain damage.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY005289-08
Application #
3260287
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1984-04-01
Project End
1992-03-31
Budget Start
1991-04-01
Budget End
1992-03-31
Support Year
8
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
Schools of Dentistry
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Quinn, K J; Schmajuk, N; Baker, J F et al. (1992) Simulation of adaptive mechanisms in the vestibulo-ocular reflex. Biol Cybern 67:103-12
Peterson, B W; Baker, J F; Perlmutter, S I et al. (1992) Neuronal substrates of spatial transformations in vestibuloocular and vestibulocollic reflexes. Ann N Y Acad Sci 656:485-99
Quinn, K J; Schmajuk, N; Jain, A et al. (1992) Vestibuloocular reflex arc analysis using an experimentally constrained neural network. Biol Cybern 67:113-22
Keshner, E A; Baker, J F; Banovetz, J et al. (1992) Patterns of neck muscle activation in cats during reflex and voluntary head movements. Exp Brain Res 88:361-74
Powell, K D; Quinn, K J; Rude, S A et al. (1991) Frequency dependence of cat vestibulo-ocular reflex direction adaptation: single frequency and multifrequency rotations. Brain Res 550:137-41
Peterson, B W; Baker, J F; Houk, J C (1991) A model of adaptive control of vestibuloocular reflex based on properties of cross-axis adaptation. Ann N Y Acad Sci 627:319-37
Wickland, C R; Baker, J F; Peterson, B W (1991) Torque vectors of neck muscles in the cat. Exp Brain Res 84:649-59
Baker, J F; Peterson, B W (1991) Excitation of the extraocular muscles in decerebrate cats during the vestibulo-ocular reflex in three-dimensional space. Exp Brain Res 84:266-78
Fukushima, K; Perlmutter, S I; Baker, J F et al. (1990) Spatial properties of second-order vestibulo-ocular relay neurons in the alert cat. Exp Brain Res 81:462-78
Khater, T T; Baker, J F; Peterson, B W (1990) Dynamics of adaptive change in human vestibulo-ocular reflex direction. J Vestib Res 1:23-9

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