Vestibular experiments in space.
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Animals↗
Biomedical subjects
Inessa B Kozlovskaya
Publications and source records attributed to Inessa B Kozlovskaya.
Electromyographic activity in the Rhesus monkey forelimb muscles during a goal directed movement and locomotion before, during and after spaceflight.
The aim of the present study was to analyse the effects of microgravity on i) the achievement of goal-directed arm movements and ii) the quadrupedal non-human primate locomotion. A reaching movement in weightlessness would require less muscle contraction since there is no need to oppose gravity. Consequently the electromyographic (EMG) activity of the monkey forelimb muscles should be changed during or after spaceflight. EMG activity of the biceps and triceps muscles during goal-directed arm movements were studied in Rhesus monkeys before, during and after 14 days of spaceflight and flight simulation at normal gravity. The EMG activity was also recorded during treadmill locomotion before and after spaceflight. When performing arm motor tasks, the delay values of the EMG bursts were unchanged during the flight. On the contrary, mean EMG was significantly decreased during the flight comparatively to the pre- and post-flight values, which were very similar. Compared with flight animals, the control ground monkey showed no change in the burst durations and mean EMG. After spaceflight, quadrupedal locomotion was modified. The animals had some difficulty in moving, and abnormal steps were numerous. The integrated area of triceps bursts was increased for the stance phase during locomotion. Taken together these data showed that spaceflight induces a dual adaptative process: first, the discharge of the motor pools of the forelimb musculature was modified during exposure to microgravity, and then upon return to Earth, monkeys changed their new motor strategy and re-adapt to normal gravity.
Adaptation, Physiological↗
The correlation between aerobic fitness and motion sickness susceptibility.
Susceptibility to motion sickness has been linked to aerobic fitness in several studies, however, these studies have not elucidated the underlying physiological mechanism by which increased aerobic fitness is related to a decreased ability to tolerate motion sickness stimuli. This pilot study provides further evidence of a relationship between aerobic fitness and motion sickness susceptibility. It also suggests that aerobic capacity is more specifically linked to signs and symptoms of vasomotor origin including stomach discomfort, nausea and/or vomiting, headache, and diaphoresis. By independently correlating vasomotor susceptibility and neurogenic susceptibility to maximum oxygen uptake, we find that vasomotor symptoms in particular are significantly increased in aerobically fit individuals. Larger studies should be conducted to confirm this relationship.
Adult↗
Smooth pursuit deficits in space flights of variable length.
The maintenance of stable vision is a primary function of the neurovestibular and sensory-motor systems. There is, however, strong evidence suggesting that space flight results in a modification of the central nervous system and subsequent control of ocular-motor responses. These changes effect those neural mechanisms which are responsible for holding images steady on the retina during brief, self-initiated, head rotations or during the voluntary pursuit of moving targets. Recent studies have shown significant saccadic intrusions in both of these experimental paradigms, including an inability to null the vestibulo-ocular reflex (VOR) during the head/eye pursuit task. The maintenance of vision, while not entirely stable, both inflight and immediately postflight is now believed to be due to neural strategies that evolve for the purpose of assisting in directing the moving target onto the retina.
NASA Center JSC↗
Countermeasures for long-term space flights, lessons learned from the Russian space program.
Physical exercises (PE) constitute the most important part of the Russian countermeasure system which is proved to be highly successful in fighting negative effects of weightlessness on the physiological systems of the body. To control the intensity and volume of the workload and also specific features of the regimens used by cosmonauts during SF there were provided monthly 3-days recordings of cosmonaut training sessions with the subsequent downlinking of the obtained information to the ground control center. Additionally once a month cosmonauts performed a fitness test that was composed of 11 minutes of locomotion on the passive treadmill including slow, middle range and maximal running. The results of 3-days recordings and fitness test allowed to evaluate correctly effectiveness of PE protocols used by cosmonauts and to form recommendations for their corrections. The effectiveness of the onboard exercise program after SF was evaluated based on results of detailed studies of alterations that were recorded in different parts of sensory-motor system.
Journal Article↗
Russian system of countermeasures on board of the International Space Station (ISS): the first results.
The system of countermeasures used by Russian cosmonauts in space flights on board of International Space Station (ISS) was based on the developed and tested in flights on board of Russian space stations. It included as primary components: physical methods aimed to maintain the distribution of fluids at levels close to those experienced on Earth; physical exercises and loading suits aimed to load the musculoskeletal and the cardiovascular systems; measures that prevent the loss of fluids, mainly, water-salt additives which aid to maintain orthostatic tolerance and endurance to gravitational overloads during the return to Earth; well-balanced diet and medications directed to correct possible negative reactions of the body to weightlessness. Fulfillment of countermeasure's protocols inflight was thoroughly controlled. Efficacy of countermeasures used were assessed both in- and postflight. The results of studies showed that degrees of alterations recorded in different physiological systems after ISS space flights in Russian cosmonauts were significantly higher than those recorded after flights on the Russian space stations. This phenomenon was caused by the failure of the ISS crews to execute fully the prescribed countermeasures' protocols which was as a rule excused by technical imperfectness of exercise facilities, treadmill TVIS particularly.
Aerospace Medicine↗
Some approaches to medical support for Martian expedition.
Medical support in a Martian expedition will be within the scope of crew responsibilities and maximally autonomous. Requirements to the system of diagnostics in this mission include considerable use of means and methods of visualization of the main physiological parameters, telemedicine, broad usage of biochemical analyses (including "dry" chemistry), computerized collection, measurement, analysis and storage of medical information. The countermeasure system will be based on objective methods of crew fitness and working ability evaluation, individual selection of training regimens, and intensive use of computer controlled training. Implementation of the above principles implies modernization and refinement of the countermeasures currently used by space crews of long-term missions (LTM), and increases of the assortment of active and passive training devices, among them a short-arm centrifuge. The system of medical care with the functions of prevention, clinical diagnostics and timely treatment will be autonomous, too. The general requirements to medical care during the future mission are the following: availability of conditions and means for autonomous urgent and special medical aid and treatment of the most possible states and diseases, "a hospital", and assignment to the crew of one or two doctors. To ensure independence of medical support and medical care in an expedition to Mars an automated expert system needs to be designed and constructed to control the medical situation as a whole.
Adaptation, Physiological↗