Dynamic Processing of Otolith Signals During Translation

Washington University, Saint Louis MO

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Abstract

DESCRIPTION (provided by applicant): The vestibulo-ocular reflexes (VORs) play an essential role as part of an integrated gaze control system to ensure stable perception of the environment during movement. While the rotational VOR (RVOR) has been well characterized at both behavioral and neurophysiological levels, the neural circuitry and computations underlying the translational VOR (TVOR) are less well understood. Despite similar functional goals, distinct temporal properties of the reflexes at both sensory and motor levels imply a requirement for different dynamic processing of canal and otolith signals. Furthermore, appropriate reflex behavior during translation is complicated by the requirement for moment-to-moment changes in the amplitude and direction of ocular deviations as a function of both current viewing location and heading direction. The study of the TVOR and its context-dependent performance thus has broad relevance in investigating basic central nervous system strategies for the successful integration of reflexive and voluntary motor behaviors. The goal of the proposed project is to identify both the strategy and the neural elements responsible for the dynamic transformation of vestibular signals in the TVOR, using an interdisciplinary approach that combines binocular eye movement recordings with single unit electrophysiology and computational modeling studies. The study will focus on the characterization of brainstem neurons that carry combinations of head and eye movement signals during translation. Experimental data will be evaluated in the context of previous modeling investigations and theoretical work will be extended and modified as required to incorporate new findings.