OTOLITH VESTIBULOOCULAR REFLEX
Principal Investigator: James Baker
Affiliation: Northwestern University
Abstract: The goal of the proposed research is to increase our understanding of the function of the vestibular otoliths in the vestibulo-ocular reflex (VOR). Semicircular canal and otolith signals are processed by vestibulo-ocular neurons and routed to the extraocular muscles to rotate the eyes in the direction opposite to head rotation. The vestibulo-ocular reflex thus maintains a constant direction of eyesight during head movement, as required for acute vision. Neural signals from the otoliths are especially important for gaze stability during vertical head movements. The proposed research will characterize vision-stabilizing eye movements produced by otoliths and explore underlying neuronal mechanisms in four series of experiments in squirrel monkeys, cats, and rats. (l) Vestibulo-Ocular Reflex during slow rotations: Eye movements and single vestibular neuron activity will be recorded during low frequency and constant velocity pitch vertical rotations in upright, on-side, and inverted head posture, to isolate vestibulo-ocular reflex signals related to otoliths. Neuronal and reflex eye movement signals will be classified as due to tilt stimulation or central nervous system estimation of head velocity. Neurons identified as projecting to extraocular muscle motor nuclei will be tested to determine whether. they carry selective components of the vestibulo-ocular reflex signal or overall motor commands. (2) Selective roles of anterior canal and otolith signals: Properties of identified brainstem vestibular nucleus neurons receiving primary input from anterior semicircular canals will be compared to those with posterior canal input, to determine if otolith-based velocity estimation signals are selectively present on anterior canal neurons and otolith-based tilt signals selectively present on posterior canal neurons. (3) Signal gating in vestibulo-ocular reflex neurons: Control of otolith signals participating in vestibular reflexes will be tested by recording vestibulo-ocular reflexes in responses to fore-aft linear motion, in monkeys gazing in different directions. Identified vestibular nucleus neurons will be classified as vestibular stimulus- linked or ocular reflex response-linked, depending on whether their responses are inverted when the ocular reflex direction is reversed with reversal of gaze direction. (4) Modeling tilt, estimator, and canal signals for vestibulo-ocular reflex: Results obtained under aims 1-3 will be incorporated in models of vestibular reflexes in an attempt to develop comprehensive models that accurately mimic vertical VOR responses. The results will add to our knowledge of gaze stability and may give insight into general brain mechanisms of sensory- motor systems.
Funding Period: 1987-09-30 - 2001-06-30
more information: NIH RePORT
- Electromyographic activity of dorsal neck muscles in squirrel monkeys during rotations in an upright or upside down postureJ Eric Killian
Department of Physiology, Northwestern University, M211, 303 E Chicago Ave, Chicago, IL 60611, USA
J Neurophysiol 93:2587-99. 2005..The results suggest that reflex contraction of neck muscles in response to passive head rotation includes an interplay of compensatory and righting responses that varies from animal to animal...
- Nonphosphorylated neurofilament protein is expressed by scattered neurons in the vestibular and precerebellar brainstemJoan S Baizer
Department of Physiology and Biophysics, University at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214, USA
Brain Res 1298:46-56. 2009..NPNFP may be a marker for those cells that are especially vulnerable to the effects of normal aging, neurological disease or disruption of sensory input...
- Neurochemical organization of the nucleus paramedianus dorsalis in the humanJoan S Baizer
Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
Brain Res 1176:45-52. 2007....
- Anterior canal neurons in cat vestibular nuclei have large phase leads during low frequency vertical axis pitchSandra C Brettler
Department of Physiology and Biophysics, Regional Primate Research Center, University of Washington, Box 357290, Seattle, WA 98195, USA
J Vestib Res 16:245-56. 2006....
- Neurochemically defined cell types in the claustrum of the catFahad E Rahman
Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, State University of New York, Buffalo, New York 14214, USA
Brain Res 1159:94-111. 2007....
- Neurochemically defined cell columns in the nucleus prepositus hypoglossi of the cat and monkeyJoan S Baizer
Department of Physiology and Biophysics, University at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214 3078, USA
Brain Res 1094:127-37. 2006..Populations of 8B3 and nNOS-immunoreactive cells are also found in PH of squirrel and macaque monkeys. The results suggest that nNOS-immunoreactive cells in PH may consist of two functionally different populations...
- Immunoreactivity for calretinin and calbindin in the vestibular nuclear complex of the monkeyJoan S Baizer
Department of Physiology and Biophysics, 123 Sherman Hall, University at Buffalo, Buffalo, NY 14214 3078, USA
Exp Brain Res 172:103-13. 2006..These findings, along with observations from rodents and cats, suggest that there are subdivisions of the MVe defined by calcium-binding proteins that are homologous across rodents, cats, and New World and Old World monkeys...
- Dynamics and directionality of the vestibulo-collic reflex (VCR) in miceJames F Baker
Department of Physiology and Institute for Neuroscience Physiology Medical, Ward 5 071, M211, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611 3008, USA
Exp Brain Res 167:108-13. 2005..Constant velocity rotations about horizontal axes elicited head velocity modulation and bias similar to that observed in the VOR. We conclude that the VCR of mice is similar to that in other mammals...
- Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkeyGabriella Sekerkova
Northwestern University Institute for Neuroscience, Searle 5 474, 320 E Superior Street, Chicago, IL 60611, USA
Exp Brain Res 164:286-300. 2005....
- Immunoreactivity for calcium-binding proteins defines subregions of the vestibular nuclear complex of the catJoan S Baizer
Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, University at Buffalo, 123 Sherman Hall, Buffalo, NY, 14214 3078, USA
Exp Brain Res 164:78-91. 2005..Immunoreactivity to parvalbumin was widespread in fibers distributed throughout the VNC. The results suggest that neurochemical techniques may help to reveal the internal complexity in VNC organization...
- Expression of calcium-binding proteins and nNOS in the human vestibular and precerebellar brainstemJoan S Baizer
Department of Physiology and Biophysics, University at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, New York 14214 3078, USA
J Comp Neurol 518:872-95. 2010..These results have important implications for the analysis of changes in that organization subsequent to aging, disease, or loss of input...