What Being in Space Does to Your Brain

TThe human body has no business in space. Without the familiar type of gravitybones can decalcify, muscles can atrophy, blood pressure can dip, heart rate can grow erratic, and fluids can rise and pool in the head, leading to pain, congestion, vision problems, and even kidney stones that less water is washed and excreted. such as urine. Exercise and proper hydration can alleviate some of these problems, but any stay in space can also exact a price, especially the long six- to 12-month shifts that many space station astronauts endure. And that’s just the physical worst. Less studied, but no less worrisome, is what long-duration spaceflight can do the cognitive abilities of an astronaut.

now, a new study published in Frontiers in physiology has some answers – mostly encouraging. While the brain, like the rest of the bodycan take a hit when leaving the planet, the researchers found that the astronauts for the most part keep their intellectual and behavioral intelligence on them, adapting dependably, if sometimes slowly, to their rarefied environments.

The research, led by neuropsychologist Sheena Dev of NASA’s Behavioral Health and Performance Laboratory, was extensive. It involved 25 astronauts who underwent a battery of 10 different cognitive tests before, during and after six-month rotations aboard the International Space Station. The subjects sat for the first series of tests 90 days before leaving Earth. This provided a baseline against which their subsequent performance could be measured. They followed that by repeating the exercises during their first and last months in altitude, and then again ten days and 30 days after returning to Earth.

There were several reasons to expect that the subjects’ performance would suffer because of their time in space. Among the psychological and emotional factors that Dev and his colleagues considered are isolation, confinement, distance from home, excessive work, disruption of circadian rhythms and sleep deprivation.

“Even on Earth, processing speed, working memory and attention are cognitive domains that can show temporary changes when an individual is under stress,” Dev said in a statement accompanying the study’s release. “If you happen to have a really busy day, but you didn’t get much sleep the night before, you may feel like it’s hard to pay attention, or that you need more time to complete tasks.”

Microgravity and exposure to cosmic radiation have also been seen as potential variables contributing to cognitive decline. While Dev and his colleagues did not speculate exactly how these factors could create problems, they did not rule out damage to brain tissue and the central nervous system.

Before starting the cognitive exercises, the astronauts had to report how many hours of sleep they had the night before and what their current level of alertness was on a scale from zero to 10. That would help determine if there are any defects in their performance are due to immediate, transient factors or long-term background stressors. Each of the tests they did later was designed to measure a particular cognitive ability.

In a test called the Visual Object Learning Task, for example, they were shown three-dimensional figures, instructed to memorize them, and then asked to pick them from a larger assortment of shapes later. In the Emotion Recognition Task, they were shown pictures of people showing a variety of emotions and told to identify them as happy, sad, angry, fearful or emotionless. In the Matrix Reasoning Task they were shown a series of shapes that changed according to a predictable pattern, even though a shape was missing somewhere in the middle of the sequence. They were then required to look at a number of other forms and find the one that correctly completed the pattern. In the Balloon Analog Risk Test, they played a video game in which they tried to blow up a balloon on the screen as big as possible without popping it. The more imaginary air pumps they gave it, the more points they would win, unless they overinflated it and it burst. This test was less a measure of the astronauts’ cognitive skills than their willingness to take chances in search of a bigger reward as opposed to playing it safe for a smaller but guaranteed one.

The good news – both for individual subjects and for the larger human enterprise of space travel – is that the abilities of astronauts have not diminished significantly in the months of pre-flight, in-orbit and post- Vol. “The astronaut’s performance was stable throughout the flight,” says Dev. “[There was] no evidence of significant deterioration or neurodegenerative decline.”

But that doesn’t mean space travel hasn’t taken a toll. The astronauts’ processing speed, working memory and attention were all slower in space than they were on Earth – with assigned tasks taking at least a little longer to complete – but no less accurate . Not all faculties were recovered at the same time or to the same extent. Reduced ability to pay attention, for example, was only experienced early in the mission before eventually returning, while processing speed was slightly slower throughout the six months in space before returning to normal. when the astronauts were back on Earth.

Performance on the emotion recognition task improved throughout the mission – a general plus when it comes to living and working with other people in close quarters. Tolerance for risk, as evidenced by the balloon test, has decreased over the six months in space, with astronauts showing less inclination to inflate the balloon to burst – a result, perhaps, of a general tendency towards caution born of living in an inherently dangerous environment. . The performance on the Matrix Reasoning Task – the exercise of completing the model – improved strongly throughout the time in the space.

“Even in areas with observed decay, the astronauts were still able to compensate and effectively complete their tasks,” Dev said in a statement.

Six months, of course, is only a fraction of the time that future crews will spend in space – even less than the minimum eight months it will take to reach Mars, never mind the time spent on the surface and the trip home. But the current results show that a species that has come of age to explore its own planet may still have the temperament and neurological skills to go much further – for much more.

As Dev summarized: “Living and working in space was not associated with widespread cognitive impairment that could suggest significant brain damage.”