Neuroimaging findings have revealed structural brain changes in response to spaceflight, including an upward shift of the brain, redistribution of cerebrospinal fluid, ventricular volume decreases, and widespread decreases in gray matter volume (Jillings et al.
2020; Roberts et al.
2017; Van Ombergen et al.
2018,
2019). These findings seem to stand in contrast to data on cognitive performance, revealing only minor impairments in response to spaceflight (Strangman et al.
2014). Whether and to what extent these changes lead to operational impairments and adverse behavioral conditions is currently not well understood. Retrospective analyses investigating the relationships between changes in cognitive performance using NASA’s cognitive test battery
WinSCAT (Kane et al.
2005) and whole-brain structural analyses are inconclusive. Higher total ventricular volume was associated with reduced accuracy on a symbol substitution task (“Code Substitution” test), and faster response speed in an n-back paradigm (“Running Memory Continuous Performance” test) (Roberts et al.
2019). Other findings from standard 6-month ISS missions have shown significant decrements in manual dexterity, dual-tasking, motion perception, and a considerable degradation of a virtual navigation, i.e., car driving task immediately after return from space (Moore et al.
2019). Whereas these effects are expected to be relatively short-lived, i.e., minutes up to several days, they are considered a substantial risk for exploratory space missions, which involve transitions between gravitational levels (Harm et al.
2015). Data from a 1-year mission using NASA’s
Cognition battery (Basner et al.
2015), assessing the cognitive performance of ten neuropsychological tests, suggests that adverse cognitive effects can persist up to 6 months postflight (Garrett-Bakelman et al.
2019). According to a review of studies that were performed during space missions, current data do not support cognitive deficits in low Earth orbit (Strangman et al.
2014). However, because of different approaches, methodologies, study durations, and small sizes, the effects of spaceflight on cognitive functions remain to be determined. However, because of different approaches, methodologies, study durations, and small sizes, the effects of spaceflight on cognitive functions remain to be determined (Mammarella
2020). Together, these data raise several key questions: (1) Could more complex cognitive and operational tasks be more sensitive to changes of inflight performance? (2) Is the neural circuitry underlying these tasks affected by spaceflight? (3) What are the long-term consequences of spaceflight on these tasks?