Prolonged Microgravity Affects Human Brain Structure and Function

Area of Science:

• Neuroscience
• Space Medicine
• Astronaut Health

Background:

• Spaceflight is known to cause widespread brain structural changes.
• The relationship between these structural changes and functional outcomes remains unclear.

Purpose of the Study:

• To investigate associations between spaceflight-induced brain structural alterations and changes in motor and cognitive function.
• To explore potential links to spaceflight-associated neuro-ocular syndrome.

Main Methods:

• Retrospective analysis of astronaut brain MRI scans (National Aeronautics and Space Administration).
• Quantification of pre- to postflight structural changes using Jacobian determinant.
• Comparison of structural changes with clinical, cognitive, and motor function data.

Main Results:

• Long-duration spaceflights (International Space Station) increased total ventricular volume (10.7%) and brain parenchyma crowding.
• Structural changes in the caudate nucleus correlated with impaired postural control.
• Alterations in motor and white matter regions correlated with cognitive task performance and reaction times.
• Astronauts with spaceflight-associated neuro-ocular syndrome showed smaller ventricular volume changes.

Conclusions:

• Brain structural changes post-spaceflight are associated with altered cognitive and motor performance.
• These findings suggest a link between structural brain changes, functional deficits, and neuro-ocular syndrome development.