CHANGES IN COMPENSATORY EYE-MOVEMENTS ASSOCIATED WITH SIMULATED STIMULUS CONDITIONS OF SPACEFLIGHT

Compensatory vertical eye movement gain (CVEMG) was recorded during pi tch oscillation in darkness before, during and immediately after expos ures to the stimulus rearrangement produced by the Preflight Adaptatio n Trainer (PAT) Tilt-Translation Device (TTD). The TTD is designed to elicit adaptive responses that are similar to those observed in microg ravity-adapted astronauts. The data from Experiment 1 yielded a statis tically significant CVEMG decrease following 15 min of exposure to a s timulus rearrangement condition where the phase angle between subject pitch tilt and visual scene translation was 270-degrees, statistically significant gain decreases were not observed following exposures eith er to a condition where the phase angle between subject pitch and scen e translation was 90-degrees or to a no-stimulus-rearrangement conditi on. Experiment 2 replicated the 270-degrees-phase condition from Exper iment 1 and extended the exposure duration from 30 to 45 min. Statisti cally significant additional changes in CVEMG associated with the incr eased exposure duration were not observed. The adaptation time constan t estimated from the combined data from Experiments 1 and 2 was 29 min .