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Geometric illusions in astronauts during long-duration spaceflight.
Gilles Clément1, Anna Skinner, Ghislaine Richard
1International Space University, Parc d'Innovation, Illkirch-Graffenstaden, France. clement@isunet.edu
Neuroreport
|September 8, 2012
Summary
Gravitational changes affect visual-spatial cognition. Astronauts in space experienced fewer geometric illusions and perceived vertical lines as shorter, similar to patients with otolith disorders.
Area of Science:
- Neuroscience
- Vestibular System Research
- Space Physiology
Background:
- Previous studies indicated reduced geometric illusions in vestibular patients and tilted healthy observers.
- A connection between vestibular and visual-spatial cognitive functions was hypothesized.
- Otolith disorders and altered gravitational input were implicated in these changes.
Purpose of the Study:
- To investigate the effect of long-duration spaceflight on geometric illusions and spatial perception in astronauts.
- To compare astronaut responses in microgravity (0 g) with ground-based (1 g) conditions.
- To determine if spaceflight-induced changes mirror those seen in otolithic patients.
Main Methods:
- Experiments were conducted with astronauts during long-duration spaceflight.
- The presence of the inverted-T geometric illusion was assessed in microgravity and on Earth.
- Astronauts' drawings of vertical line lengths were measured in orbit and on the ground.
Main Results:
- The inverted-T geometric illusion was less prevalent in astronauts in 0 g compared to 1 g.
- Astronauts in orbit drew vertical lines that were shorter than those drawn on the ground.
- These findings align with observations in otolithic patients, who also perceive vertical lengths as smaller.
Conclusions:
- Impaired processing of gravitational input during long-duration spaceflight affects astronauts' mental representation of verticality.
- Spaceflight-induced alterations in spatial perception are comparable to those in otolithic patients.
- Astronauts demonstrated recovery of baseline spatial perception within one week after returning to Earth.
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