About the Off-Vertical Axis Rotator (OVAR) Laboratory



    Astronauts have reported episodes of disorientation relatively frequently in microgravity and on return to Earth. Such episodes have the potential to interfere with an astronaut's performance and to jeopardize safety. The OVAR Laboratory is primarily concerned with understanding the mechanisms by which judgments of orientation are made in order to understand the causes of the episodes of disorientation and hopefully to provide ways of eliminating such episodes. The laboratory uses oculomotor and perceptual tasks to measure where astronauts feel themselves to be in three-dimensional space and in which direction they are moving or facing. This subjective location is called the egocenter and its location and direction is determined by both otolith and somatosensory inputs. Experiments on Earth which modify these inputs alter people's judgments of where they are and which direction they are facing. Vestibular disorders affect orientation
    Off Vertical Rotation - Measurement of Perception and Video Recording of Eye Movements Off Vertical Rotation - Measurement of Perception and Video Recording of Eye Movements
    perception and it seems that, corresponding with the recovery process, over time the balance Off Vertical Rotation - Measurement of Perception and Video Recording Of Eye Movementsbetween vestibular and somatosensory input in determining orientation is altered. It is anticipated that similar changes will take place during prolonged microgravity and then again another re-balancing between vestibular and somatosensory input will occur on return to a 1-g environment. This laboratory is the only laboratory that has initiated a direct investigation of the changes in the straight-ahead direction in astronauts.

    We measure the subjective straight-ahead by psychophysical tests requiring verbal responses and oculomotor responses. In a typical psychophysical test the subjects is asked to indicate when a spot crosses their perceived straight-ahead or to return the gaze to the straight-ahead position from various off-center positions. In a typical oculomotor task the subject will be required to look straight ahead during a period of darkness in order to determine where gaze shifts, and eye position will be measured using videooculography.

    The Off-Vertical Axis Rotator allows investigators to study eye movements and motion perception while continuously changing the orientation of the subject relative to gravity. This device is currently being used to examine adaptive changes in otolith-mediated responses following short-duration Shuttle flights (DSO 499), as well as examining vestibular-autonomic interactions.

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