Short-term microgravity effects simulation does not affect fNIRS measures of cerebral oxygenation changes induced by...

Area of Science:

• Neuroscience
• Space Medicine
• Human Physiology

Background:

• Space exploration, particularly to Mars, is increasing.
• Long-duration missions pose cognitive challenges due to microgravity effects like fluid shifts.
• Functional near-infrared spectroscopy (fNIRS) monitors brain activity but needs validation in microgravity.

Purpose of the Study:

• To investigate the impact of simulated microgravity on cerebral oxygenation measured by fNIRS during cognitive tasks.
• To determine if fNIRS requires adjustments for cephalic fluid shifts in microgravity.

Main Methods:

• Simulated microgravity using head-down tilt at various inclinations.
• Cognitive assessment using the Toulouse N-back Task with varying difficulty.
• Cerebral oxygenation monitoring via fNIRS (measuring HbO and HbR).

Main Results:

• Cognitive task difficulty increased, leading to reduced accuracy and longer response times.
• Head-down tilt inclination did not significantly impact task performance.
• Increased cognitive load correlated with higher HbO and lower HbR, independent of tilt angle.

Conclusions:

• fNIRS measurements of cognitive load are robust under simulated microgravity conditions.
• No correction for fluid shifts is needed when using fNIRS for cognitive monitoring in space.