Neurocognitive performance is enhanced during short periods of microgravity

In order to maintain and improve space mission safety and success, there has been growing interest in the effects of microgravity on cognitive processing. While findings today are quite inconsistent, those studies reporting a decrement in cognitive performance have not been able to distinguish between the direct influence of microgravity and any associated impact of stress. Furthermore, the currently available findings rely primarily on behavioral observations and there has been no study of the underlying neurophysiological responses.
PURPOSE: To determine the effects of microgravity on neurophysiological processing during a mental arithmetic task (executive function).
METHODS: During the normal- and microgravity phases of a parabolic flight, four levels of a mental arithmetic task were presented on a touchscreen tablet. The latency between the appearance of the problem and the participants’ response was identified as reaction time. In addition visual evoked potentials N1 and P2 were determined using an active EEG-system and analyzed using source localization algorithms.
RESULTS: An increase in reaction time occurred with increasing levels of task difficulty. During the most complex levels, reaction time was significantly reduced during microgravity. This observation was independent of previous parabolic flight experience as well as the use of anti-motion-sickness medication. P2-amplitude in the superior frontal and medial frontal gyrus was significantly reduced in the microgravity condition localized.
CONCLUSION: Cortical processes seem enhanced during microgravity, and previously reported impairments in cognitive performance are attributable to an increased amount of stress rather than weightlessness itself.