The illusion on the ISS: how weightlessness affects the sensation of astronauts

© Illustration RIA Novosti . A. Polyaninova Alexander Misurkin to the ISSThe illusion on the ISS: how weightlessness affects the sensation of astronauts© Illustration RIA Novosti . A. Polyanina

Already in Ancient Greece philosophers have said that our senses deceive us. They pointed to the refraction of objects in water and distortion dimensions on removal, insisting that truth is capable of showing only the mind. Distorted perception we call an illusion, though for the most part this «deception» does not prevent us to build a picture of the world. In space ordinary earthly illusions acquire new properties. All of these effects are caused by the human body’s response to the lack of gravity.

Perception of space regulates the vestibular apparatus, the organ vosprinimayutsya changes in head position and body in space and the direction of movement of the body. It is located in the inner ear is a complex clumps of cells and calcareous formations.

The vestibular apparatus consists of semicircular canals and statolith apparatus. In the area there are sensitive hair cells immersed in the otolith membrane, topped gelatinous substance. There are ear stones (otoliths) — education, pressure on different parts of the membrane depends on the position of the body in space. But when a person is in weightlessness, these stones pressure is not exerted. Therefore, deprived of a natural way of orientation in space, the astronauts begin to experience different illusions.

the fraud was characterized by the sense of rotation of his own body around, and moving along any axis. At first glance, kinetic illusions seem to be a fun ride, but finish is «riding» on their own is impossible. Such illusions turned in the coordinate: the people felt that their body inclined to the left or right, backward or forward, and is sometimes upside down.

Weightlessness can cause a person to feel literally like the floor was slipping from under his feet and the walls falling. Some astronauts also noted an illusory sense of position of different body parts: «it seems that sitting hunched over, and in fact lie exactly in a sleeping bag», «hands are on top, and it seems that from the bottom,» showed itself proprioceptive illusion.

Along with the illusory responses in 72% of the astronauts had difficulty tracking a moving target and fixing her gaze continued discoordination manifestations — misses when trying to grab objects, hit his head on the panel when floating inside the station. Analysis using the eog and mathematical methods have found a relationship between the orientation illusions and disorders in oculomotor reactions.

«We conduct pre-and post-flight inspection of all crew members to understand the levels at which there is a change in the Central nervous system, — says senior researcher of the laboratory of vestibular physiology, Institute of biomedical problems RAS George Ekimovsky. — To examine how serious are manifested vestibular disorders, we use several methods, including those developed by our laboratory. The complex includes electrooculography with a special set of tests and a unique software, developed for astronauts at the Institute. We also use the method of videophotography, that is supported sensorineural connection between the visual activity of the eye, the condition of the vestibular and nervous systems of the body as a whole.»
© Illustration RIA Novosti . A. Polanicazdroj the trajectory of the eye when the object trackingThe illusion on the ISS: how weightlessness affects the sensation of astronauts© Illustration RIA Novosti . A. Polanicazdroj the trajectory of the eye when tracking an object

The method of eog is based on the detection of a potential difference that occurs when the movement of the eyeball. The eye itself is a dipole in which the cornea is in General electropositive relative to the retina. To register potentials around the eyes set cross the electrodes. If the eyeball is at rest, the electrodes are located at equal distances from the positive and negative poles. If the patient directs attention toward one of the electrodes moves closer to the positive pole and the second to negative. In the result, the latter becomes electronegative and the electropositive. The sign of the potential it is possible to establish the direction of movement of the eyes.

© Illustration RIA Novosti . A. Polyaminates spontaneous eye movementsThe illusion on the ISS: how weightlessness affects the sensation of astronauts© Illustration RIA Novosti . A. Polyaminates spontaneous eye movements
Says George Ekimovsky: «If illusions occur only during the first three days, it’s called adaptation, but if they continue after this time, it is possible to speak about occurrence of space motion sickness. The so-called state in which the violation of the perception of space are added certain symptoms or a syndrome (collection of symptoms) that violate the working life of an astronaut in zero gravity. After returning to Earth the astronauts sometimes also arise illusions, similar to the «space». One of the curious Ostpolitik effects was that some of the astronauts after landing a few days, we were experiencing the movement of the Earth. They are physically «felt», as the planet rushes in outer space.»

The study of the reactions of the astronauts in weightlessness helps to treat imbalance and dizziness ordinary people. There are two options for treatment. The first method includes pharmacotherapy and the second is to conduct a series of training of the vestibular apparatus, similar to those conducted for preflight training of cosmonauts.

In the Institute of biomedical problems of RAS is preparing a new experiment Virtual2 for the study of the reactions of the vestibular apparatus in weightlessness. At the moment the equipment is tested on Earth under conditions simulating weightlessness on the ISS.