[Bioelectric activity of the human brain during 180-day antiorthostatic hypokinesia and during the rehabilitation period].

Cerebral bioelectric activity of 18 healthy test subjects, aged 31-40, was examined during and after their 182-day head-down tilting. The test subjects were divided into a group that performed countermeasures (exercise, muscle stimulation) against hypokinesia-induced disorders and a control group. During the study EEG changes were most pronounced in the controls: alpha-rhythm amplitude, frequency and index decreased, slow wave frequency reduced, whereas index of zonal differences and amplitude of beta- and slow waves increased. Phasic changes in the central nervous system excitability in response to a flickering light of 6-25 cps were found. Typical changes in spontaneous EEG during a 3 min pulmonary hyperventilation test were enhanced. The study gives evidence that the dynamics of spontaneous EEG as well as cerebral bioelectric activity in response to flickering light and pulmonary hyperventilation are important indicators of the cerebral function, especially of the cortical activity decrease.