[Pattern of spontaneous oculomotor activity in weightlessness and the readaptation period]

The results of one part Spontaneous Oculomotor Activity Study of Soviet-Bulgarian experiment "Labyrinth" conducted with the participation of 5 cosmonauts prior to and after 10- and 241-day flight are presented. Two cosmonauts have also been studied in-flight. The experiment was conducted with the use of automated data controlling and processing system "Zora" developed by the Bulgarian specialists on a personal computer basis. The horizontal and vertical electrooculograms were recorded in the subjects with eyes closed, open and open but shaded by opaque glasses with the gaze directed forward and in extreme left, right, up and down directions of the gaze. It is found that in the first 3 day of space flight especially when locking visual input, there is an increase in spontaneous activity of "swimming" and saccadic nature or spontaneous nystagmus mainly in the vertical direction. There have been sharp decreases in the rate of eye movement and increase of an amplitude when placing the eyes in the extreme positions (especially in up-down directions) accompanied by correcting saccades or adaptive nystagmus. The post- and inflight changes in the severity and pattern of spontaneous oculomotor responses were similar.