The goal of the study was to determine whether exercise may serve as a preventive measure and/or countermeasure to the adverse effects of microgravity on the central nervous system using a microgravity analog design. This overarching goal was subdivided into four sub-aims: 1) Investigate exercise as a preventive and/or countermeasure to mitigate the effects of microgravity on motor behavior and cognition; 2) Investigate exercise as a preventive and/or countermeasure to mitigate the effects of microgravity on central nervous system (CNS) plasticity and function objectified with structural and functional neuroimaging techniques; 3) Investigate the potentially mediating role of exercise on the relationship between changes in behavior and CNS plasticity and function; and 4) Identify if physical health markers on the single subject level can predict behavioral adaptability to a microgravity environment.
To further explain any effects of bed rest and exercise, data was leveraged from a normative control study. For this study a group of NASA ground personnel completed the same neurocognitive and sensorimotor measures and MRI protocol as the bed rest subjects. These assessments were repeated three times over a time course that matches up with the time course of the bed rest measurements. This allowed a comparison of the effects of bed rest and exercise in supine position during bed rest to the time course of these outcome measures in normative healthy control subjects.
Long-duration bed rest results in water redistribution in areas that are largely overlapping with those areas in which gray matter changes are observed. Gray matter decreases co-occurred with water increases and vice versa. This indicates that during the study the gray matter changes observed on the T1 MRI largely reflects water redistribution. No significant differences were observed in changes in focal cerebral water contact or white matter microstructure between the bed rest exercise group and the bed rest control group, neither during bed rest or during the post bed rest recovery period. Bed rest was associated with functional connectivity changes between several sensorimotor and vestibular brain regions. Investigators also observed significant group by time interaction effects in changes in functional connectivity during bed rest and during the period post bed rest. During bed rest there was an increase in connectivity between the right premotor cortex and a large cluster in the superior frontal gyrus in bed rest exercise subjects while at the same time bed rest control subjects showed a decrease in functional connectivity between these regions. In addition, post bed rest there was an increase in connectivity between the right posterior parietal cortex and a cluster in the left postcentral gyrus in bed rest exercise subjects while at the same time bed rest control subjects showed a slight decrease in functional connectivity between these regions. These results indicate that aerobic and resistance exercise during bed rest can at least partially mitigate the effects of bed rest on the functional connectivity between sensory and motor brain regions and on recovery post bed rest.
|Mission||Launch/Start Date||Landing/End Date||Duration|