Changes of brain response induced by simulated weightlessness.

Area of Science:

• Neuroscience
• Human Physiology
• Aerospace Medicine

Background:

• Understanding the effects of altered gravity on the human brain is crucial for space exploration.
• Previous studies have indicated physiological changes during simulated weightlessness, but brain response modifications require further investigation.

Purpose of the Study:

• To investigate the changes in brain responses, including EEG power spectra and event-related potentials (ERPs), under simulated weightlessness conditions.
• To compare brain activity during 15-degree head-down tilt (HDT) with 45-degree head-up tilt (HUT).

Main Methods:

• Electroencephalogram (EEG) power spectra analysis at rest and during mental arithmetic.
• Measurement of event-related potentials (ERPs) for somatosensory, selective attention, and mental arithmetic tasks.
• Comparison of brain responses between head-down tilt (HDT) and head-up tilt (HUT) conditions.

Main Results:

• Head-down tilt (HDT) revealed a notable inhibition of brain function.
• The '40Hz' activity increment observed during HUT mental arithmetic was significantly reduced during HDT.
• HDT induced a positive potential effect across all measured ERPs, with an elongation of the slow negative wave associated with mental arithmetic and memory.

Conclusions:

• Simulated weightlessness profoundly affects brain function, as evidenced by changes in EEG and ERPs.
• The observed brain inhibition and altered processing dynamics suggest significant neural adaptations to altered gravity.
• Systematic study of brain function changes during actual space flight is warranted to understand these profound effects.