VOA科学技术2023--Study: Longer Space Flights Affect Areas in Brain

Study: Longer Space Flights Affect Areas in Brain

A new study has found that areas of the brain containing fluid expand when astronauts are on space missions for six months or longer. The American space agency NASA funded the study.

The brain areas are called cerebral¹ ventricles. They contain cerebrospinal fluid, a clear and watery³ liquid that flows in and around the brain and spinal² cord. The fluid helps protect the brain against sudden impact. The fluid also removes waste products.

Researchers based their research on brain scans of 30 astronauts. They found that it took three years for the ventricles to fully⁴ return to normal size after long space missions. The results mean that astronauts may need to wait at least three years between longer space missions.

Heather McGregor is a University of Florida brain scientist. She was the lead writer of the study, which appeared in the publication Scientific Reports. She told the Reuters news agency that if the ventricles do not have enough time to get back to normal size, they could have less space to expand on a following trip to space. This could affect the brain's ability to deal with the changes in gravity that astronauts face.

Rachael Seidler is a University of Florida professor of applied⁵ physiology⁶ and kinesiology. She was also a writer of the study. She said, "the impact of ventricular expansion is currently not known," and that scientists need to do more studies on the subject.

She added that the expansion likely compresses the area of the brain around the spaces. To compress means to press, squeeze or make smaller.

On Earth, valves in the body's vascular⁷ system prevent fluid from staying at our feet due to gravity. But in space, without gravity, the valves push the fluid more towards the head. Seidler said this is what likely causes the ventricular expansion. As a result, the brain sits higher in the skull⁸.

The study involved 23 male and seven female astronauts from the U.S., Canadian and European space agencies. The average age of the astronauts was 47. Eight of the astronauts traveled on space shuttle missions that lasted about two weeks. Eighteen were on International Space Station (ISS) missions of about six months. The other four took part in ISS missions that lasted about a year.

The astronauts who went on short missions experienced little or no ventricular size change. A size increase occurred in astronauts after missions of six months or longer. There was no difference in those who went on missions for six months compared to those who went on year-long missions.

The fact that enlargement did not worsen after six months could be good news for future Mars missions. Astronauts may spend two years in microgravity during trips to Mars. The study results are also good news for people thinking about going on short space tourism flights, Seidler added.

Low gravity causes other changes in the human body, as well. These include decreases in bone and muscle mass, some changes to the heart and lung system, and issues with the balance system in the inner ear.

Longer space missions might also increase cancer risk because of greater exposure to solar radiation.

Words in This Story

fund -v. to pay for or provide some money for some activity or project

impact -n. a) the action of one object hitting another, or the force with which one object hits another. ; b) the strong effect something has on another thing or person.

physiology -n. the scientific study of how people's and animals' bodies function

kinesiology -n. the scientific study of how people's and animals' bodies move

occur -v. to happen

exposure -n. placement in a situation where dangerous or damaging things can affect you

1 cerebral   

adj.脑的，大脑的；有智力的，理智型的

参考例句：

• Your left cerebral hemisphere controls the right-hand side of your body.你的左半脑控制身体的右半身。
• He is a precise,methodical,cerebral man who carefully chooses his words.他是一个一丝不苟、有条理和理智的人，措辞谨慎。

2 spinal   

adj.针的，尖刺的，尖刺状突起的；adj.脊骨的，脊髓的

参考例句：

• After three days in Japan,the spinal column becomes extraordinarily flexible.在日本三天，就已经使脊椎骨变得富有弹性了。
• Your spinal column is made up of 24 movable vertebrae.你的脊柱由24个活动的脊椎骨构成。

3 watery   

adj.有水的，水汪汪的；湿的，湿润的

参考例句：

• In his watery eyes there is an expression of distrust.他那含泪的眼睛流露出惊惶失措的神情。
• Her eyes became watery because of the smoke.因为烟熏，她的双眼变得泪汪汪的。

4 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

5 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

6 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

7 vascular   

adj.血管的，脉管的

参考例句：

• The mechanism of this anomalous vascular response is unknown.此种不规则的血管反应的机制尚不清楚。
• The vascular changes interfere with diffusion of nutrients from plasma into adjacent perivascular tissue and cells.这些血管变化干扰了营养物质从血浆中向血管周围邻接的组织和细胞扩散。

8 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。