The main objective of this experiment is to evaluate the alterations in brain cortical activity induced by micro- and hypergravity conditions.

A secondary objective is to correlate changes in brain cortical activity and brain oxygenation level with neurocognitive performance.

Another secondary objective is to differentiate between the influences of hemodynamic and electro cortical changes and the influence of stress on cognitive performance alterations

Inclusion Criteria:

• Healthy volunteers (men or women)
• Aged from 18 to 65
• Affiliated to a Social Security system and, for non-French resident, holding a European Health Insurance Card (EHIC)
• Who accepted to take part in the study
• Who have given their written stated consent
• Who has passed a medical examination similar to a standard aviation medical examination for private pilot aptitude (JAR FCL3 Class 2 medical examination). There will be no additional test performed for subject selection.

Subjects will be staff member of the team or of other teams participating in the parabolic flight campaign

Exclusion Criteria:

• Person who took part in a previous biomedical research protocol, of which exclusion period is not terminated
• Persons with prior serious injuries to their head
• Persons who take any medication or drugs influencing their central nervous system or cognitive performance
• Pregnant women