[EFFECT OF VOLUNTARY BREATH-HOLDING AND COGNITIVE LOADS ON REGIONAL CEREBRAL BLOOD FLOW AND BIOELECTRIC ACTIVITY OF THE BRAIN].

Cerebral blood flow and bioelectric activity were studied in 10 normal volunteers in order to assess cerebrovascular reactivity during different types of functional testing. The transcranial Doppler was used to measure linear blood velocity (LBV) in the middle cerebral artery (MCA) during maximal voluntary breath-holding (apnea), controlled verbal association test and tactile memory test. Simultaneous electroencephalography (EEG) registered the bioelectric activity of the brain cortex.

[Scatological investigations during 105-day isolation].

Dynamics of the gastrointestinal functioning was reconstructed by analysis of the scatological data from volunteered subjects before, on days 16, 35, 45, 60, 90 and after completion of 105-day isolation experiment. The analysis showed that scatological investigations performed in the conditions imitating life in an exploration vehicle environment are instrumental in detecting deviations in the GI function indicative of pancreas excretory and hepar biliary excretion and synthetic hypofunction that can be responsible for intestinal dysfunction. Normalization of scatological parameters following the experiment witnesses to functional genesis of the changes observed during the exploration mission simulation.

[The influence of extended exposure in artificial hypercapnic environments on the function of external respiration and gas exchange].

Effects of artificial hypercapnic atmosphere were studied in a series of ten 40-d experiments with participation of 42 volunteers aged from 20 to 61 years. Partial pressure of carbon dioxide was maintained at 27 +/- 2 mm Hg (3.4-3.

[Sensitivity of the respiratory center to carbon dioxide during prolonged exposure of humans to gas environment with unchanging level of hypercapnia].

Effects of moderate CO2 concentrations (2.2-3.2%) on external respiration were studied in a series of extended (30-d) continuous tests with volunteered human subjects.