Psychophysical studies of visuo-vestibular interaction in microgravity

Area of Science:

• Human physiology
• Space medicine
• Neuroscience

Background:

• Spaceflight poses unique challenges to human sensory systems.
• Understanding sensory adaptation is crucial for astronaut health and mission success.
• Vection, the sense of self-motion, is influenced by visual-vestibular interactions.

Purpose of the Study:

• To investigate vertical linear vection in cosmonauts during long-term space flights.
• To compare vection responses between short-term and long-term microgravity exposure.
• To analyze the adaptation phases of sensory-motor systems in space.

Main Methods:

• Sinusoidal velocity profile stimulation was used to induce vertical linear vection.
• Vection responses were measured in two long-term spaceflight cosmonauts and one short-term exposed cosmonaut.
• Eye/hand sensorimotor task performance was assessed concurrently.

Main Results:

• Eye/hand sensorimotor pursuit ability remained stable across all subjects.
• Vertical vection frequency and phase response were altered in the short-term cosmonaut during initial adaptation.
• Vection responses in long-term cosmonauts (tested at 4, 10, and 14 weeks) demonstrated significantly greater stability.

Conclusions:

• Sensory-motor adaptation to microgravity occurs in distinct phases.
• Long-term spaceflight leads to more stable vection responses compared to early adaptation.
• Findings support the hypothesis of phased adaptation to microgravity environments.