RESUMO
Effects of support deprivation on gaze fixation were studied in Macacas mulatta immersed up to the sternum (two animals) and the neck (one animal) with the use of electrooculography and measurement of head motion velocity. Deterioration of gaze fixation parameters after five hours of sternum-high immersion was similar to what had been observed in experiments aboard the biosatellites, i.e. increased saccade amplitude and VOR gain, and decreased maximal head velocity. Five-hour neck-high immersion had a more pronounced effect on the head velocity and, besides, altered the pattern of head movement toward target. It can be surmised that support deprivation is one of the spaceflight factors impacting time and precision of gaze fixation. Water immersion of primates is an adequate model for studying mechanisms of the microgravity effects on coordination of eye and head movements toward gaze fixation.
