This study investigated the impact of zero gravity on brain function using transcranial magnetic stimulation (TMS). Researchers measured the resting motor threshold (rMT) in 10 healthy adults at baseline, during zero gravity periods induced by parabolic flight, and post-flight. A significant 12.6% decrease in rMT was observed during weightlessness, suggesting neurophysiological changes occur during brief periods of zero gravity. Potential explanations include brain shift within the skull, increased cortical excitability, changes in intracranial pressure, and neuromuscular system effects. The findings highlight the need for further research on human brain function in altered gravity conditions.

Bashar W. Badran, Kevin A. Caulfield, Claire Cox, James W. Lopez, Jeffrey J. Borckardt, William H. DeVries, Philipp Summers, Suzanne Kerns, Colleen A. Hanlon, Lisa M. McTeague, Mark S. George, Donna R. Roberts