With NASA preparing to send manned mission into deep space in the coming years, agency scientists have started to explore the effects of long-term stay in a zero-gravity environment on human health, particularly on the brain.
In previous space missions, NASA astronauts have reported that they suffered from balance issues and even experienced perceptual illusions while they were in microgravity onboard the International Space Station (ISS).
A new study conducted by the University of Michigan (UM) and funded by NASA examined how weightless environments affect both the structure and function of the brain in order to find out how long it would take for an astronaut to recover after returning to Earth.
Rachael D. Seidler, director of the Neuromotor Behavior Laboratory in Michigan, led team researchers in carrying out brain imaging and behavioral assessments on a group of astronauts.
The researchers asked the astronauts to finish timed obstacle courses and examined their ability to picture and manipulate a three-dimensional object mentally before and after going on space missions.
The mental manipulation of the 3D object, also known as spatial memory test, was also performed while the astronauts are onboard the ISS. This was combined with tests on their sensory motor adaptation as well as computer-aided exercises that required them to think and move simultaneously.
The tests in space were conducted shortly after the astronauts arrived on the ISS, mid-way through their stay on the orbital facility and toward the end of their six-month spaceflight.
The brains of the NASA astronauts were examined using functional and structural magnetic resonance imaging (MRI) before and after their mission on the ISS.
Seidler said what they are looking at is the volume of different brain structures and whether these structures change in shape or size while the astronauts are in zero gravity.
According to the researchers, the brain imaging and the behavioral assessments were both vital allowing them to determine the link between physical changes in the astronauts' brains and those in their behavior.
"On Earth, your vestibular - or balance - system tells you how our head moves relative to gravity, but in space, the gravity reference is gone," Seidler pointed out.
Seidler added that this absence of gravity is what causes the perceptual illusions that astronauts typically experience, as well as their difficulty in coordinating the movement of their heads and eyes.
The researchers noted that such issues could result in severe consequences for space travelers, particularly during their transition from one gravitational environment to another.
In situations such as landing on the red planet Mars, astronauts will have to perform tasks, including using tools and maneuvering a rover, without impairments to their senses and movement.
Photo: NASA Goddard Space Flight Center | Flickr