Brains on Mars: how space travel affects cognitive function

Who wants to go to Mars? Surprisingly, not so few people. The idea of ​​colonizing the red planet has been circulating in society for more than a year, but so far no one has been growing potatoes on Mars. There are many reasons for this. One of the main ones is the need to calculate all aspects of such a long, dangerous and unpredictable journey, not to mention being on a planet with a very unfriendly environment. Engineers are engaged in spacecraft, planet rovers, dwellings and spacesuits for future colonists. But man is at the center of all this technological wealth, and understanding how his body will feel during long space flights and during life on another planet is a priority. Therefore, scientists from the University of South Carolina decided to conduct a study of the brain, its structure and all the possible cognitive changes that can occur in it, if traveling to Mars. How exactly does the brain change depending on the time spent in space, how does this affect human behavior, and is there any fear for the future mission to colonize Mars? The answers to these questions we learn from the report of the research group. Go.

Study basis

The mysterious and mysterious Mars, which has repeatedly visited the role of the central location of science fiction works, is very close to our home planet Earth, on the scale of the Universe of course. The minimum distance between the planets is 54.6, the maximum is 401, and the average is about 225. And all this in millions of kilometers. For ordinary people, this is a tremendous distance, and for space connoisseurs - a short walk. However, to overcome such distances with the technologies available to us, it will take from 150 to 300 days, depending on the speed of movement, the position of the Earth relative to Mars and the flight path. For many astronauts who visited the ISS, this is not so long, but there is a difference between the orbital station and the space between the planets.



Earlier studies of the brain after being on the ISS have already been conducted. The result of these studies was the identification of vertical brain displacement, the accumulation of eloquent ( Eloquent ) tissues * of the brain in the vertex (crown) and the expansion of the ventricles of the brain.

Eloquent brain tissue * - this term refers to the area of ​​the brain, the removal of which will lead to the loss of linguistic abilities, sensory problems, partial or complete paralysis.

Researchers note that previously obtained data on changes occurring in the body of astronauts during and after being in orbit, although they are known to scientists, are not fully understood. So, for example, the etiology and functional significance of the structural changes in the brain are still unclear. In the work that we are considering today, scientists decided to examine in more detail such anomalies and find out how related are structural changes in the brain before / after flight and the cognitive / motor characteristics of a person.



In addition, scientists decided to link the study of the structure of the brain of astronauts and the already known syndrome associated with space travel. In 2017, it was found that a long stay on the ISS caused some ophthalmological changes in a number of astronauts: changes in visual acuity, “cotton” spots and choroidal folds on the retina (ischemic changes in the retina), swelling of the optic nerve head. NASA gave these changes the common name - SANS ( spaceflight-associated neuro-ocular syndrome ), i.e. neuro-ocular syndrome associated with space travel.



Researchers believe that changes in the brain are directly related to SANS and can affect other aspects of the body's work, including cognitive functions.

Research results

The study of the brain of astronauts was carried out in several stages, during each of which scientists paid attention to a certain indicator. Next, we consider the points of the results of the analyzes and tests.

Analysis of volume by brain tissue segments

No significant changes before and after the flight in the total volume of gray or white matter were detected either by the shuttle astronauts or the astronauts with the ISS.





Table 1: data on changes in the volume of gray and white matter in astronauts before / after the flight on the shuttle and on the ISS.



As expected, a significant increase in the total ventricular volume was found in astronauts after the flight on the ISS, but not on astronauts after the flight on the shuttle (10.7% - ISS and 0% - shuttle, 1A ).





Image No. 1



For ISS astronauts, the percentage change in ventricular volume for the left lateral, right lateral, third and fourth ventricles was: 17.1% ± 6 7.3%, 15.2% ± 6 8.4%, 15.4% ± 6 4.9% and 0.83% ± 6 4.57%, respectively. The value of% ∆VV (percentage change in total ventricular volume) varied before / after the flight depending on its duration ( 1B ). Interestingly, the value of% ∆VV in younger astronauts was higher than in older astronauts ( 1C ).

Assessment of local changes in brain boundaries

Given the previously established fact of brain tissue displacement due to being on the ISS, scientists analyzed the local displacement of brain tissue in the interface between the brain and cerebrospinal fluid. Cosmonauts who underwent long space missions noted significant local changes in the structure of the brain (image below).





Image 2: MRI image of an astronaut’s brain showing the accumulation of eloquent brain tissue in the vertex region (red color) and local tissue displacement (blue color).



During the study, crowding of the parenchymal * brain tissue in the crown was observed, which was accompanied by crowding of the motor, premotor and primary sensorimotor regions. A displacement of brain tissue along the edges of the ventricle was also revealed, which is consistent with previous observations regarding ventricular enlargement.

Parenchyma * - functional brain tissue, consisting of neurons and neuroglia. Injuries to this area of ​​the brain can lead to cognitive impairment and even death.

At the same time, astronauts who experienced short-term space flights (shuttle) showed no deviations.

The relationship between brain structural changes and motor skills

Table 2: test results for astronauts motor skills before / after shuttle flights and before / after being on the ISS.



Motility tests showed that local structural changes in the left caudate nucleus nevertheless led to a decrease in postural * control ( 3A ).

Postural reflex * - a set of reactions and reflexes that ensure the preservation of a certain position of the body or part of the body in space.

Image No. 3: Local changes in the brain parenchyma affecting the results of motor tests.



Tests to restore body position after a fall and to maintain a fixed position also showed an effect on local motor changes in the brain parenchyma ( 3B ).



The time spent by astronauts on the tests “walking” and “squatting” ( 3C ) was more than normal, which indicates the influence of local changes in the cingulate cortex, which plays an important role in the implementation of executive functions.



Summing up the intermediate result, changes in the brain caused by a prolonged stay on the ISS (in the context of the study) directly affect a person's ability to perform certain tasks related to motility. These deviations cannot be called critical or negatively affecting everyday or professional tasks, but the fact of their presence indicates the need for further study of this aspect of the human brain.



Scientists also decided to test the relationship between% ∆VV values ​​and motor test results (table below).





Table 3: Correlation between the percentage change in the total ventricular volume and the percentage change in the results of testing the motility of 8 astronauts (7 people - ISS and 1 - shuttle).



Significant correlation was found in tests to restore body position after a fall and to maintain a fixed position. This suggests that subjects with a larger increase in% ∆VV experienced difficulties with postural control due to spaceflight.

The relationship between brain structural changes and cognitive function

All subjects before the study underwent WinSCAT ( Windows Spaceflight Neuro-Cognitive Assessment Tool ) testing, standard for all astronauts, evaluating neurocognitive functions.





Screenshot of an earlier version of WinSCAT (found here ).



This program consists of various questions and tasks (logic, mathematics, etc.).



However, WinSCAT results show no correlation with flight duration. Therefore, as scientists say, this program cannot be taken into account in this study.





Table No. 4: statistics of tests of WinSCAT astronauts before and after flights to the ISS.



After the flight, astronauts showed a significant decrease in the accuracy of performing CDS tests (coded sequences) and training tests. However, there was an improvement in the speed of the CDS test and the attention-saving test.



Then the scientists decided to check the brain volume and cognitive functions, as well as the relationship between them. During this study, 3 sites of white matter were identified that are associated with a change in the response time to CPT (cognitive tasks).





Image No. 4: Local deformation of the brain parenchyma associated with the success of the continuous performance test.



Brain images of astronauts after the flight, in which the reaction time to the test underwent minimal reduction, showed the presence of structural changes in the three regions of white matter, namely, the change in volume.



The ventricular volume, as in the case of the test for decoding encoded sequences, also had a negative correlation with the success of continuous performance tests. Astronauts whose ventricles increased in volume after the flight showed a decrease in the accuracy and speed of the tests.



Of the 12 astronauts who had previously been on the ISS for a long time, there were four who had signs of SANS: three had choroidal folds on the retina, and the fourth showed increased intracranial pressure and swelling of the optic nerve disc through lumbar puncture.



Curiously, the four astronauts with SANS had significantly less changes in the volume of the ventricles of the brain than the eight without SANS: 12.8% versus 6.5%. However, scientists are not ready to consider these observations to be one hundred percent correct and representative with respect to all astronauts who have experienced long space flights, since the number of subjects in the study is too small. But in the future this unusual observation will receive a more detailed study.



If you combine the results of all tests and MRI, then a definite picture emerges of the relationship between space travel and structural changes in the brain.



Firstly, this is a temporary correlation - changes in the brain become more pronounced with an increase in the time spent in space. Secondly, age - the effect of long space travel is more pronounced among young astronauts. Thirdly, cognitive - all found changes in the brain in one way or another affected the cognitive functions of astronauts, the quality of implementation of which decreased after flights.



The study involved 19 astronauts: 6 men and 1 woman (average age 46.7 ± 2.1 years) who flew the shuttle (14.7 ± 1.6 days), as well as 10 men and 2 women (average age 47.5 ± 4.8 years) who stayed on the ISS (162.7 ± 21.8 days). On the one hand, such a number of subjects may not be enough to describe all aspects of the influence of space on changes in the human brain, but this is enough to unequivocally state that there are such changes. Therefore, they must be taken into account when planning long space flights and the possible colonization of Mars.



For a more detailed acquaintance with the nuances of the study, I recommend that you look into the report of scientists and additional materials to it.

Epilogue

In this work, it was found that being in space has a direct effect on changes in the structure of the human brain and, as a consequence, on its cognitive functions. A similar statement could be made without conducting research, however, it was necessary to establish exactly what changes are taking place and how exactly they affect astronauts after long flights.



Tests of motor skills and thought processes showed a decrease in the speed and accuracy of their execution, and MRI made it possible to determine exactly which parts of the brain were affected and are the source of such changes in cognitive functions.



It is also worth considering that the study participants were trained astronauts who spend a lot of time in preparation before flights, affecting not only their physical, but also their mental state. If professionals were affected by the negative correlation between space and cognitive functions, then what can we say about ordinary people.



This is precisely the importance of this study. Since human eagerness to explore space and colonize planets cannot be appeased, it is necessary to be as prepared as possible for such a dangerous and unpredictable occupation.



The authors of our study consider that it is necessary to give priority to the human brain if we want to successfully plow the expanses of the galaxy. First of all, in their opinion, it is necessary to focus on studying the adaptation of the brain to space and to develop new methods that can improve and speed up this process.



Space travel is not an easy task and requires taking into account all the details, all possible options for the development of events, all problems and all solutions. This should concern not only the technical component, because in the center of all these shuttles, rockets, satellites, planet rovers and other amazing equipment there will always be a man - a creature with its own advantages and disadvantages.





Thank you for your attention, stay curious and have a great weekend everyone, guys! :)



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