The influence of microgravity on cerebral blood flow and electrocortical activity
Changes in gravity conditions have previously been reported to influence brain hemodynamics as well as neuronal activity. This paper attempts to identify a possible link between changes in brain blood flow and neuronal activity during microgravity. Middle cerebral artery flow velocity (MCAv) was measured using Doppler ultrasound. Brain cortical activity (i.e., cortical current density) was measured using electroencephalography. Finger blood pressure was recorded and exported to generate beat-by-beat systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), and cerebrovascular conductance index (CVCi). Seventeen participants were evaluated under normal gravity conditions and microgravity conditions, during 15 bouts of 22-s intervals of weightlessness during a parabolic flight. Although MAP decreased and CO increased, MCAv remained unchanged in the microgravity condition. CVCi as the quotient of MCAv and MAP increased in microgravity. Cortical current density showed a global decrease. Our data support earlier data reporting a decrease in the amplitude of event-related potentials recorded during microgravity. However, the general decrease in neural excitability in microgravity seems not to be dependent on hemodynamic changes.
KeywordsParabolic flight EEG Transcranial Doppler ultrasound MCA
We would like to thank each of our participants for delivering 100% of data although their world was turned upside down! We would like to thank Brain Products and ADInstruments and MedCat (The Netherlands) for renting out equipment that made our life much easier in these extreme conditions. It is a pleasure working with you and we are extremely thankful for your support. And of course, for the brilliant hardware you deliver! Finally, we would like to thank two unknown reviewers for their valuable comments, which improved the quality of the paper.
Compliance with ethical standards
Conflict of interest
All authors have approved the final article. This study was made possible by a grant from German Space Agency (50WB1561). Beside all authors declare no conflict of interest.
- Bock O, Howard IP, Money KE, Arnold KE (1992) Accuracy of aimed arm movements in changed gravity. Aviat Space Environ Med 63:994–998Google Scholar
- Bock O, Fowler B, Comfort D (2001) Human sensorimotor coordination during spaceflight: an analysis of pointing and tracking responses during the “Neurolab” space shuttle mission. Aviat Space Environ Med 72:877–883Google Scholar
- Bock O, Abeele S, Eversheim U (2003) Sensorimotor performance and computational demand during short-term exposure to microgravity. Aviat Space Environ Med 74:1256–1262Google Scholar
- Fowler B, Manzey D (2000) Summary of research issues in monitoring of mental and perceptual-motor performance and stress in space. Aviat Space Environ Med 71:A76–A77Google Scholar
- Griffiths PD (2008) Vascular supply of the brain. In: Standring S (ed) Gray’s anatomy, 40 edn. Elsevier, Churchill LivingstoneGoogle Scholar
- Jüngling S, Bock O, Girgenrath M (2002) Speed-accuracy trade-off of grasping movements during microgravity. Aviat Space Environ Med 73:430–435Google Scholar
- Saradjian AH, Paleressompoulle D, Louber D, Coyle T, Blouin J, Mouchnino L (2014) Do gravity-related sensory information enable the enhancement of cortical proprioceptive inputs when planning a step in microgravity? PLoS One 9:e108636. https://doi.org/10.1371/journal.pone.0108636 CrossRefGoogle Scholar
- Schneider S, Askew CD, Brummer V, Kleinert J, Guardiera S, Abel T, Struder HK (2009) The effect of parabolic flight on perceived physical, motivational and psychological state in men and women: correlation with neuroendocrine stress parameters and electrocortical activity. Stress 12:336–349. https://doi.org/10.1080/10253890802499175 CrossRefGoogle Scholar