Cerebral hemodynamics and cognition during simulated microgravity
LE3 .A278 2020
2020
Mekary, Saïd
Acadia University
Bachelor of Kinesiology
Honours
Kinesiology
Microgravity has been shown to be a significant stressor on many physiological systems in the body due to the redistribution of fluids that occurs in the absence of gravitational force. The cardiovascular, endocrine, and musculoskeletal systems have all been proved to undergo significant alterations because of this stressful environment, but there is scarce literature surrounding the effects of microgravity on cerebral hemodynamics and cognition. Therefore, this study aims to determine if the altered levels of blood and oxygen reaching the brain during simulated microgravity has an effect on cognitive performance.A total of 39 participants aged 22.1±5.95 years participated in the study. Each participant took part in a single 2-hour testing session. Each participant completed an hour and a half of simulated microgravity using the head-down- tilt (HDT) method by laying still on a table angled at -6°. Two cognitive tasks were completed during the testing session; one at the beginning of the session and one following the simulation of microgravity to measure any differences in cognitive performance. Cerebral oxygenation was monitored throughout the testing session using near-infrared spectroscopy (NIRS). Cerebral oxygenation was found to be significantly higher during the simulation of microgravity compared to the upright seated position and horizontal seated position (p<0.05). Non-executive task performance remained stable, but executive task performance significantly improved after the HDT as reaction time significantly decreased from 1058±195 msec to 950±158 msec (p<0.05). Cerebral oxygenation was found to remain stable during the non-executive tasks, but was found to be significantly heightened during the executive task post HDT (p<0.05). Acute microgravity was found to significantly alter the levels of cerebral oxygenation. These alterations were also correlated with differences in cognitive performance. As the race for Mars intensifies, more deep-space missions occur, and commercial spaceflight approaches reality, it is necessary that we have a complete understanding of physiological response to microgravity to ensure safety and efficiency for these missions, as well to ensure feasibility for this industry.
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https://scholar.acadiau.ca/islandora/object/theses:3365
