Preliminary analysis of sensory disturbances and behavioral modifications of astronauts in space.

Behavioral modifications of astronauts over time spent in microgravity conditions was investigated according to an ethological approach based on video recordings during the Spacelab-1 mission. The method consisted of a description and a quantification of motor activity of a subject (movement and orientation) while performing working tasks. Each period of observation lasted 20 min, on days 1, 2, 3, 4, 7, 9, and 10. This provided a rather consistent frequency for behavioral sampling. The data were correlated with the findings of physiological experiments performed during the same spaceflight. Results revealed an increase in frequencies of certain motor outputs (e.g., yaw head and body movements, hand gripping, feet anchoring) which favored several specific sensory inputs (visual and tactile information). In addition to the appearance of head-down orientations while manipulating floating objects and during periods of body free-floating, the astronaut developed a new representation of the space and the objects around him in microgravity. These behavioral interpretations are discussed in the light of sensorimotor interactions and cognitive events.