Dynamics of Brain Potentials in Volunteers for Modeled Head-to-Pelvis G-Loads (+gz) on a Short-Arm Human Centrifuge

A series of +Gz runs on a short-arm human centrifuge (SAHC) was performed in support of the proposal to design a centrifuge as a source of gravity aboard piloted exploration vehicles. Nine male volunteers participated in a 3-stage experiment with exposure to 2.1 g, 2.41 g and 2.92 g. The runs were accompanied by electroencephalography monitoring (EEG). Classic visual EEG analysis revealed characteristic and individual changes in the brain bioelectrical activity. Spectral analysis provided information about relative powers (RP) of the EEG bands: delta-2 (2–4 Hz), tetha (4–8 Hz), alpha (8–13 Hz) and beta-1 (13–24 Hz) in 19 leads total. The body of RP changes made it possible to trace dynamics of the brain functional response to different g-loads. The greatest tetha RP decay (up to 15.5 %) with the simultaneous beta RP rise up to 8.4 % at 2.92 g pointed to activation of the cortex of cerebral hemispheres due to attenuation of the inhibitory effect of the nonspecific brain system. The neurophysiological individual typological patterns and absence of alpha RP changes implied a reasonably good CNS adaptation to all SAHC g-loads.