The vestibular system serves to maintain orientational, postural, and visual stability during head movements. The vestibulo ocular reflex (VOR) is an important vestibular mechanism that rotates the eyes to maintain binocular fixation on a target during head movement, thus maintaining clear and stable vision. The VOR is actually a set of reflexes activated by two forms of head acceleration; angular (the AVOR), driven by the semicircular canals, or linear (the LVOR), driven by the otoliths. The otolith organs sense linear accelerations caused by both head translation and head tilt relative to gravity, yet each form of motion requires different compensatory responses. Thus, the LVOR is comprised of both translational and tilt forms. The vestibular system may undergo functional changes in response to development, aging, or disease processes, but is able to modify its behavior such that binocular fixation is maintained during head movements. This process, known as adaptive plasticity, is well recognized in the AVOR, but is largely unstudied in the LVOR. We will study adaptive plasticity of the AVOR and translational LVOR in response to novel visual/vestibular challenges. The resulting behavior of these challenges on the AVOR and LVOR will be assessed and compared. This research will elucidate the extent to which the AVOR, translational LVOR, and tilt LVOR, are driven by shared neural pathways, or if control of each subsystem is independent. Selective adaptation of the VOR will be exploited to formulate structural and functional characteristics of central VOR pathways, and suggest stages of neuronal processing where adaptation may occur. In addition, VOR and motion perception mechanisms share common sensory inputs, as well as the common goal of maintaining spatial orientation. To determine if VOR and motion perception share common pathways, the effects of AVOR and translational LVOR adaptation on the perception of motion and tilt will also be examined. The study of LVOR adaptation will directly contribute to our understanding of how the vestibular system adapts to natural development, disease and aging processes, and to the unnatural gravitational environments encountered during air and space travel. A better understanding of LVOR adaptation will catalyze tests of susceptibility to motion sickness (including the form experienced in space flight), and countermeasures to prevent or reduce this syndrome.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC004153-05
Application #
6612961
Study Section
Special Emphasis Panel (ZRG1-IFCN-5 (04))
Program Officer
Platt, Christopher
Project Start
1999-08-01
Project End
2006-07-31
Budget Start
2003-08-01
Budget End
2006-07-31
Support Year
5
Fiscal Year
2003
Total Cost
$261,709
Indirect Cost
Name
University of Rochester
Department
Neurology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Seidman, Scott H; Au Yong, Nicholas; Paige, Gary D (2009) The perception of translational motion: what is vestibular and what is not. Ann N Y Acad Sci 1164:222-8
Au Yong, N; Paige, G D; Seidman, S H (2007) Multiple sensory cues underlying the perception of translation and path. J Neurophysiol 97:1100-13