VESTIBULAR LABYRINTH IN HEALTH AND DISEASE

Washington University, Saint Louis MO

Investigators

Abstract

Vestibular research has seen recent major advances with the advent of new tools, techniques and ideas. These advantages have been realized in studies of both the central and peripheral vestibular systems in studies performed on both terrestrial and microgravity. Advances have been made in the understanding of the contributions of biomechanics, including intra labyrinthine pressure to the formation of the response dynamics of the semicircular canal nerves. Experiments have also revealed that canal dynamics of the semicircular canal nerves Experiments have also revealed that canal plug does not completely inactivate the response of the plugged canal but shifts the phase and gain (dynamics) of the response. There have been advances in the study of the metabolism and formation of the otolith that is no longer regarded as a static entity but is viewed as a structure in the dynamic flux of remodeling. The concept of a "fragile" otolith has emerged to explain why there can be the occurrence of benign paroxsismal positional vertigo thought due to gravitational responses of the semicircular canals when otolithnic particles break off and become lodged upon the cupula. Studies in microgravity have bearing on the tilt-translation hypothesis of otolithic organ function. Concepts of the function of the vestibular nuclei have been completely revised by studies showing that signals related to head motion that are expressed in the nuclei are not seen when the head is free and the animal makes a voluntary movement. Finally, new tools have allowed scientists to begin to examine the frames of reference relative to the gravitoinertial vector in head free experiments. Clinical testing of peripheral labyrinthine function has also been revolutionized as it is now possible to test the function of single semicircular canals as well as the integrity of some central pathways using simple head thrust procedures. Therefore we desire to hold a forum paring basic scientists and clinicians on the same panel to discus and point out these advances and their meaning. To promote the educational aspects of the conference we hope to award up to 30 fellowships to students and postdoctoral fellows to acquaint them with the exciting new developments in vestibular research.