[BEHAVIORAL AND FUNCTIONAL VESTIBULAR DISTURBANCES AFTER SPACE FLIGHT. 2. FISHES, AMPHIBIANS AND BIRDS]

Area of Science:

• Vestibulogy
• Space Biology
• Comparative Physiology

Context:

• Understanding the effects of microgravity on biological systems is crucial for long-duration space missions.
• The otolith system, responsible for balance and spatial orientation, is particularly sensitive to gravitational changes.

Purpose:

• To review the impact of weightlessness on the otolith system and associated functional shifts in various vertebrate species.
• To compare vestibular responses across fishes, amphibians, birds, and mammals under simulated or actual spaceflight conditions.

Summary:

• Weightlessness does not significantly impair otolith system development in embryonic vertebrates; in some cases, it may even be beneficial.
• Post-flight, both lower vertebrates (fish, amphibians) and mammals (including humans) exhibit similar vestibular and motor function alterations, such as changes in vestibulo-ocular reflex and coordination.
• Unusual motor behaviors, like looping in tadpoles, may stem from altered otolith stimulation, mirroring sensory illusions in astronauts.

Impact:

• Provides insights into the fundamental mechanisms of vestibular adaptation and habituation to altered gravity.
• Highlights the potential of using animal models for studying spaceflight-induced vestibular changes due to physiological similarities and experimental tractability.
• Informs strategies for mitigating space adaptation syndrome and ensuring astronaut health and performance during space exploration.