PT  - JOURNAL ARTICLE
AU  - Heather R. McGregor
AU  - Kathleen E. Hupfeld
AU  - Ofer Pasternak
AU  - Nichole E. Beltran
AU  - Yiri E. De Dios
AU  - Jacob J. Bloomberg
AU  - Scott J. Wood
AU  - Ajitkumar P. Mulavara
AU  - Roy F. Riascos
AU  - Patricia A. Reuter-Lorenz
AU  - Rachael D. Seidler
TI  - Impacts of Spaceflight Experience on Human Brain Structure
AID  - 10.1101/2022.02.09.479297
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.02.09.479297
4099  - http://biorxiv.org/content/early/2022/02/10/2022.02.09.479297.short
4100  - http://biorxiv.org/content/early/2022/02/10/2022.02.09.479297.full
AB  - Spaceflight induces widespread changes in human brain morphology. It is unclear if these brain changes differ with varying mission durations or one’s history of spaceflight experience (e.g., number of prior missions, time between missions). Here we addressed this issue by quantifying voxelwise post-flight changes in gray matter volume, white matter microstructure, extracellular free water (FW), and ventricular volume in a sample of 28 astronauts. We found that longer missions induced greater ventricular expansion and larger FW displacement at the top of the brain. A greater number of prior missions was associated with white matter microstructure declines in a tract supporting voluntary leg movement. Longer inter-mission intervals were associated with greater ventricle expansion, with compensatory ventricular expansion observed only in those crewmembers with inter-missions intervals of 3 years or longer. Longer missions therefore induce more extensive brain fluid shifts, and the ventricles may require at least 3 years to recover post-flight.Competing Interest StatementYED, NEB, APM are employed by KBR. The other authors declare no competing interest.