What happens to the brain in weightlessness?

02.12.2018 - NASA, Space
What happens to the brain in weightlessness?

For anybody not a secret that NASA took on an impossible task: to send humans to Mars by 2030. Why? Because it is enough to understand that a typical trip would take from three to six months, and the crew will have to stay on the planet up to two years before the alignment of the planets will allow him to return home. This means that astronauts have to live in conditions of reduced (micro) gravity for three years at least — this greatly exceeds the current record for continuous stay in space, the Russian cosmonaut Valeriy Polyakov: 438 days.

In the early days of space travel, scientists worked hard to figure out how to overcome the force of gravity so that the rocket could like from a catapult to launch into space and to land people on the moon. Today gravity also remains on the agenda of science, but this time we are more interested in how reduced gravity affects the health of astronauts, especially their brains. In the end, we evolved to exist in earth’s gravity (1 g), but not in the weightlessness of space (0 g) or microgravity to Mars (0.3 g).

“Brain in a VAT”

So how does the brain cope with the microgravity environment? In short, very bad — however, information is limited. We know that astronauts face redden and swell in weightlessness is a phenomenon affectionately called “effect Charlie brown”. This happens mostly because the fluid, consisting mainly of the blood (cells and plasma) and cerebrospinal fluid shifting to the head, causing the face to become puffy and rounded, and his legs are thin.

These fluid shifts are also associated with “disease space” (similar to sea), headaches and nausea. Recently they were also associated with blurred vision because of pressure rise while increasing blood flow; the brain floats in the upper part of the skull, exerting pressure on him. Despite the fact that NASA believes the impairment and displacement of the brain the main risk to the health of any person on Mars, find out what causes it and how to prevent it, has not yet happened.

Professor of physiology and biochemistry Damien Bailey of the University of South Wales believes that certain parts of the brain end up with too much blood, because the blood accumulates nitric oxide is an invisible molecule that is usually there. The arteries that supply blood to the brain, relax, therefore, revealed stronger. As a result of this rise in blood flow blood brain barrier “shock” the brain becomes overloaded. The water slowly accumulates, the brain swells, pressure increases.

What happens to the brain in weightlessness?

Imagine if the river overflows its banks. The most important thing in all this is that in some parts of the brain not getting enough oxygen. This is a big problem, which may explain the blurred vision and other effects that manifest themselves on the abilities of the astronauts to think, concentrate, reason and move.

A trip on the “vomit comet”

To test the idea, scientists must implement it in practice. But instead of asking NASA trip to the moon, they just decided to break free from the shackles of earth’s gravity, modeled weightlessness on a special plane called “the vomit comet”, the “vomit comet”.

Lifting into the air and then descending, the aircraft to carry up to 30 parabolic shapes per flight to simulate the feeling of weightlessness. The free fall lasts only 30 seconds, but the face manages to swell and in those half a minute.

Safely securing all equipment, the scientists measured among the eight volunteers, each of which made one trip each day for four days. They measured blood flow in different arteries, supporting brain, using a portable Doppler ultrasound makes high frequency sound waves bounce off circulating red blood cells. Also measured the level of nitric oxide in blood samples taken from veins of the forearm, as well as other molecules, including free radicals and specific brain proteins (which reflect structural brain damage) — they could tell whether you open the blood brain barrier by force.

Initial findings have confirmed exactly what was expected. The levels of nitrogen oxides increased after repeated “attacks” of weightlessness, and this coincided with the increase in blood flow, especially in arteries supplying the back part of the brain. The blood-brain barrier was opened, although no evidence of structural brain damage was not.

Now scientists plan to continue these studies with more detailed assessments of changes in blood and fluid in the brain using imaging techniques like magnetic resonance to confirm the results. They also want to consider the possibility of introducing countermeasures such as rubber pants, which create a negative pressure in the lower part of the body and help “pump” blood out of the brain of the astronaut — as well as drugs counteracting the increase nitric oxide. The results of such works can not only improve the health of astronauts in space travel, but also provide valuable information on why “gravity” is useful for the brain.

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