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| NASA tests human brains in zero gravity |
There are several tests and tasks an astronaut has to perform before taking a ride to space such as obstacle courses to test their physical fitness and agility, test of spatial memory, which is the ability to visualise a three-dimensional picture. The astronauts undergo these tests thrice - before, mid-way and at the end of a standard six-month spaceflight.
According to Dr Rachael D Seidler, principal investigator and director at the University of Michigan's neuromotor behaviour laboratory, both the behavioural assessment and brain imaging are important for identifying the link between the brain's physical changes and those in behaviour.
Here are five out-of-the-world facts about human body zero gravity:
1. Growing tall is a common phenomenon in space. In zero gravity, the spine expands freely, causing the person grow in height. An average person can grow up to 3 percent of his or her current height in space.
2. Distribution of blood changes in space. Due to Earth's gravity, blood runs more to the lower extremities of human body. But in space, the process changes and astronauts have puffier faces and thinner legs according to blood flow.
3. Astronauts often face difficulty in remembering the fact that Earth has gravity once they come back. Dropping things and breaking them is very common among them.
4. Muscle mass, that gives you the strength to lift your body and move around, reduces in amount in space. This happens as the body starts shedding muscle mass because it does not need much to operate in zero gravity. Same thing happens to bone density. Astronauts have to work out for at least two hours a day to keep their muscle mass and bone density in proper shape.
5. In space, it's hard to sleep. Astronauts have reported seeing bright flashes of light while they were trying to rest. These flashes are actually cosmic rays that travel in space. They make it difficult to get some shut-eye!
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The US space agency is examining changes in both brain structure and function in astronauts on board the International Space Station (ISS) to determine how long it takes for them to recover after returning from space.
Previous research and first-hand reports suggest that humans have a harder time controlling physical movement and completing mental tasks in microgravity.
Astronauts have experienced problems with balance and perceptual illusions - feeling as if, for example, they are switching back and forth between right-side-up and upside down.
NASA researchers are using both behavioural assessments and brain imaging.
Astronauts complete timed obstacle courses and tests of their spatial memory, or the ability to mentally picture and manipulate a three-dimensional shape, before and after spaceflight.
The spatial memory test also is performed aboard the ISS, along with sensory motor adaptation tests and computerised exercises requiring them to move and think simultaneously.
Astronauts are tested shortly after arriving aboard the station, mid-way through and near the end of a six-month flight.
"We are looking at the volume of different structures in the brain and whether they change in size or shape during spaceflight,” said principal investigator Rachael D Seidler, director of University of Michigan’s neuromotor behaviour laboratory in a statement.
Functional MRIs involve astronauts completing a task during the imaging which will show researchers which parts of the brain they rely on to do so.
According to Seidler, both the behavioural assessment and brain imaging are important to help identify the relationship between physical changes in the brain and those in behaviour.
"On Earth, vestibular - or balance - system tells how head moves relative to gravity but in space, the gravity reference is gone,”
"That causes these perceptual illusions, as well as difficulty coordinating movement of the eyes and head.”
These difficulties could have serious consequences for astronauts, especially when changing between gravitational environments, such as landing on Mars.
In those cases, astronauts will need to be able to perform tasks such as using tools and driving a rover, and they must be capable of escape in a landing emergency.
Identifying the physical mechanisms behind changes in behaviour and how much time it takes to adapt will help researchers determine how best to help space explorers compensate.
The results could also reveal whether astronauts return to “normal” post-flight because the brain changes back, or if the brain instead learns to compensate for the changes that happened in space.
Ref:
http://www.newindianexpress.com/world
