Gu Jianwen, Wang Tao, Shi Tiejun, Nie Chuang, Yang Yuan, Gao Junfeng, Zhang Li, Liu Xin, Wang Yuan, Strategic Support Force Characteristic Medical Center, Neurosurgery, Aerospace Clinical Medicine, Manned Space Medical Team, and Special Service Medicine
In long-term spaceflight, factors such as weightlessness, vibration, noise, radiation, electromagnetic fields, small cockpit environment, and changes in circadian rhythms may cause changes in the central nervous system of the human body, which may have an impact on human physiology, ergonomics, psychology and cognition. For example, weightlessness may affect brain function by reducing the blood supply to the brain, vibrations and noise may affect the brain's ability to perceive and react, radiation and electromagnetic fields may cause damage to the nervous system, and a small cabin environment and changes in circadian rhythms may cause sleep disturbances and mood problems.
In addition, long-term spaceflight may also cause structural and functional changes in the central nervous system, for example, the gray matter volume of the brain may decrease, the number and connections of neurons may change, and the release and absorption of neurotransmitters may be affected. These changes may lead to clinical manifestations such as cognitive decline, mood problems, sleep disturbances, etc.
Long-term space flight may have the following effects on the brain:
- Changes in cognitive function: including changes in attention, memory, decision-making ability, etc.
- Structural changes in the brain: may cause changes in gray and white matter.
- Neurological problems: such as neurotransmitter imbalances, etc.
- Radiation exposure: Increases the risk of damage to brain cells.
- Stress and fatigue: Psychological stress and physical fatigue caused by long-term exposure to special environments.
- Sleep disorders: Affect the normal recovery and function of the brain.
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Microgravity effects: have an effect on blood circulation and neuronal activity in the brain.
To reduce these effects, astronauts take a range of measures during space missions, including cognitive training, monitoring brain function, providing proper nutrition and rest, and more. Upon return to Earth, rehabilitation and evaluation will also be carried out. In order to adapt to long-term spaceflight and interstellar navigation, it is necessary to understand exactly what happens to the central nervous system during long-term space flight, and the physiological, ergonomic, psychological and cognitive effects of these changes. There are many studies on the changes in the central nervous system in long-term aerospace at home and abroad.
南卡罗来纳医科大学的研究人员“The effect of prolonged spaceflight on cerebrospinal fluid and perivascular spaces of astronauts and cosmonauts”的研究论文，发布了一项大型合作研究的结果，该研究涉及长时间太空飞行对大脑的影响。
Human missions to Mars and the construction of lunar outposts are two of the main goals that several space agencies aim to achieve. This requires an understanding of how the human brain adapts to long-term exposure to low gravity. Extensive changes in brain structure and cerebrospinal fluid (CSF) redistribution were observed in MRI after the Space Shuttle flight, including ventricular enlargement without parenchymal atrophy, upward brain displacement with vertex subarachnoid space (VSA) narrowing, and alterations in water diffusivity.
The clinical relevance of these alterations is unknown, but they may be related to spaceflight-associated neuro-ocular syndrome (SANS), a disease characterized by structural changes in the eye that affects 40% to 60% of NASA astronauts on long-term missions internationally to the Space Station (ISS). While visual changes in Roscosmos (ROS) astronauts have been noted after space flights, there are no published reports using the SANS classification developed by NASA to describe them.
The study aims to determine whether spaceflight induces volumetric changes in the perivascular space (PVS), a network of whole-cerebral perivascular channels along which cerebrospinal fluid-interstitial fluid (ISF) exchange occurs. To investigate the relationship between PVS expansion and spaceflight-related alterations in VSA and lateral ventricles (LVs); In addition, since differences in the adoption of microgravity countermeasures may affect the extent of spaceflight-related changes, changes in these compartments were exploratively compared in a joint international study of brain MRI before and after space flight for U.S., European, and Russian crews.
MRI was used to analyze the changes in the perivascular space (PVS) of astronauts from NASA and the European Space Agency and Roscosmos astronauts after a 6-month space flight on the International Space Station (ISS). An increase in the volume of basal ganglia PVS and white matter PVS (WM-PVS) was found after space flight, which was more prominent among NASA crew members than among Roscosmos crew members. In addition, both staff members showed a similar degree of lateral ventricular enlargement and reduced subarachnoid space at the apex, which correlated with WM-PVS enlargement. Since all crew members experience the same environment on the ISS, the difference in WM-PVS expansion may be due to factors such as the use of countermeasures and differences in high-resistance movement patterns, which may affect cerebral fluid redistribution. In addition, the NASA astronauts who developed SANS had a larger WM-PVS volume before and after the flight than the unaffected astronauts. These results provide evidence for a potential link between WM-PVS fluids and SANS.
Research on brain function on the space station
In 2015, an in-depth study of the human brain was conducted on the International Space Station (ISS).
Space navigation has a special effect on the central nervous system of astronauts, and scientists have conducted a series of experiments in the microgravity environment on the space station to study these effects, so as to reduce the risk of future astronauts on missions to asteroids, Mars, and even more distant deep space.
During a year-long mission to the International Space Station (ISS) astronauts Scott Kelly and Russian cosmonaut Mikhail Kornienko, NASA astronauts conducted a group of research that would give researchers a deeper understanding of the cognitive and psychological effects of long-term spaceflight on astronauts. In the study, the researchers looked at loneliness, fatigue, and the effects of the alternating day-night cycle and microgravity on astronauts when they were awake. The study, which is twice as long as typical NASA studies, will give researchers a deeper understanding of the cognitive and psychological effects of long-term space travel on astronauts. At the same time, researchers are able to obtain a large amount of health data about humans.
Some of these studies include:
"Real-time Flight Fatigue Assessment Tool for Individual Neurocognition" (Cognitive Experiment)
This is a series of tests that study how changes in physical conditions (e.g., microgravity effects, lack of sleep) affect the brain during space flights. These 10 are computer-tested and measure many aspects of an astronaut's cognitive function and provide real-time feedback.
"Mental vigilance self-test (reflexivity self-test)"
This is an assessment test that allows all astronauts to track their fatigue levels and takes 5 minutes. Astronauts sometimes experience sleepiness from taking sleeping pills and shifts, and this tiredness changes their biological clocks. In addition, changes in sleep cycles and extravehicular activities can potentially adversely affect astronauts' work effectiveness and resilience.
Research on the Neurocognitive Effects of Space Navigation: Degree, Lifespan, Neural Basis (Neural Networks)
The "neural network" test is dedicated to studying the changes in the structure and function of the brain caused by space travel, including muscle control and vision. The study will examine the structural and functional changes in the astronauts' brains through magnetic resonance imaging (MRI) after their return.
"Sleep Actiography and Light Exposure Detector" (Sleep Experiment on the International Space Station)
This set of instruments is used to monitor the light exposure and astronauts' activities, and plays a pivotal role in ensuring the quality of astronauts' sleep. The astronauts' sleep is monitored by a "sleep log" and a wearable electronic device called "Actiwatches". The "sleep log" is turned on for 15 minutes a day for seven days and is monitored every three weeks, while the "Actiwatches" are worn by the astronauts throughout the mission. In addition to this, the researchers will also focus on subjective evaluations of astronauts' reaction sensitivity.
Research on Behavioral Issues Related to Loneliness and Claustrophobia (Astronaut Diary Analysis)
Astronaut diaries were studied using the "Astronaut Diary Review Analysis" to analyze their mood and physical health. The results of this research will help in the preparation of future space missions to the space station, Mars and beyond.
A study on the effects of long-term exposure to microgravity on fine motor fine motor skills
This one-year program examines hand-eye coordination. In this project, the astronauts were asked to perform a series of interactive activities on a touch-screen writing board. This is the first study of human fine motor skills in microgravity for long periods of time, adaptation to microgravity at different stages, and rehabilitation after returning to Earth.
Study on the Habitability Assessment of the International Space Station".
The study focused on collecting observations of the habitable area of astronauts on the space station. The design of the space station is important because it is the only living and working space for the two astronauts (NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko on this mission) for a year. Therefore, the researchers gathered the above relevant information in order to design a more comfortable space station in the future.
The series of studies conducted this and others on the space station will help researchers better understand how the human brain survives in weightlessness after leaving Earth, and these studies will also have a positive impact on the field of neuroscience. Stay tuned for more information on this and other research this month, which will lead to a clearer understanding of the human brain living in space.