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Sarma MS, Shelhamer M. The human biology of spaceflight. Am J Hum Biol 2024; 36:e24048. [PMID: 38337152 PMCID: PMC10940193 DOI: 10.1002/ajhb.24048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
To expand the human exploration footprint and reach Mars in the 2030s, we must explore how humans survive and thrive in demanding, unusual, and novel ecologies (i.e., extreme environments). In the extreme conditions encountered during human spaceflight, there is a need to understand human functioning and response in a more rigorous theoretically informed way. Current models of human performance in space-relevant environments and human space science are often operationally focused, with emphasis on acute physiological or behavioral outcomes. However, integrating current perspectives in human biology allows for a more holistic and complete understanding of how humans function over a range of time in an extreme environment. Here, we show how the use of evolution-informed frameworks (i.e., models of life history theory to organize the adaptive pressures of spaceflight and biocultural perspectives) coupled with the use of mixed-methodological toolkits can shape models that better encompass the scope of biobehavioral human adjustment to long-duration space travel and extra-terrestrial habitation. Further, we discuss how we can marry human biology perspectives with the rigorous programmatic structures developed for spaceflight to model other unknown and nascent extremes.
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Affiliation(s)
- Mallika S. Sarma
- Human Spaceflight Lab, Johns Hopkins School of Medicine, Baltimore, MD 21215
| | - Mark Shelhamer
- Human Spaceflight Lab, Johns Hopkins School of Medicine, Baltimore, MD 21215
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Li Z, Wu J, Zhao T, Wei Y, Xu Y, Liu Z, Li X, Chen X. Microglial activation in spaceflight and microgravity: potential risk of cognitive dysfunction and poor neural health. Front Cell Neurosci 2024; 18:1296205. [PMID: 38425432 PMCID: PMC10902453 DOI: 10.3389/fncel.2024.1296205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
Due to the increased crewed spaceflights in recent years, it is vital to understand how the space environment affects human health. A lack of gravitational force is known to risk multiple physiological functions of astronauts, particularly damage to the central nervous system (CNS). As innate immune cells of the CNS, microglia can transition from a quiescent state to a pathological state, releasing pro-inflammatory cytokines that contribute to neuroinflammation. There are reports indicating that microglia can be activated by simulating microgravity or exposure to galactic cosmic rays (GCR). Consequently, microglia may play a role in the development of neuroinflammation during spaceflight. Prolonged spaceflight sessions raise concerns about the chronic activation of microglia, which could give rise to various neurological disorders, posing concealed risks to the neural health of astronauts. This review summarizes the risks associated with neural health owing to microglial activation and explores the stressors that trigger microglial activation in the space environment. These stressors include GCR, microgravity, and exposure to isolation and stress. Of particular focus is the activation of microglia under microgravity conditions, along with the proposal of a potential mechanism.
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Affiliation(s)
- Zihan Li
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Jiarui Wu
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Tianyuan Zhao
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Yiyun Wei
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Yajing Xu
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Zongjian Liu
- Department of Rehabilitation, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Xiaoqiong Li
- School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Xuechai Chen
- Beijing International Science and Technology Cooperation Base for Antiviral Drugs, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
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Dontre AJ. Weighing the impact of microgravity on vestibular and visual functions. LIFE SCIENCES IN SPACE RESEARCH 2024; 40:51-61. [PMID: 38245348 DOI: 10.1016/j.lssr.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/03/2023] [Accepted: 12/27/2023] [Indexed: 01/22/2024]
Abstract
Numerous technological challenges have been overcome to realize human space exploration. As mission durations gradually lengthen, the next obstacle is a set of physical limitations. Extended exposure to microgravity poses multiple threats to various bodily systems. Two of these systems are of particular concern for the success of future space missions. The vestibular system includes the otolith organs, which are stimulated in gravity but unloaded in microgravity. This impairs perception, posture, and coordination, all of which are relevant to mission success. Similarly, vision is impaired in many space travelers due to possible intracranial pressure changes or fluid shifts in the brain. As humankind prepares for extended missions to Mars and beyond, it is imperative to compensate for these perils in prolonged weightlessness. Possible countermeasures are considered such as exercise regimens, improved nutrition, and artificial gravity achieved with a centrifuge or spacecraft rotation.
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Affiliation(s)
- Alexander J Dontre
- School of Psychology, Fielding Graduate University, 2020 De La Vina Street, Santa Barbara, CA 93105, USA; Department of Communications, Behavioral, and Natural Sciences, Franklin University, 201 South Grant Avenue, Columbus, OH 43215, USA.
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4
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Desai RI, Kangas BD, Luc OT, Solakidou E, Smith EC, Dawes MH, Ma X, Makriyannis A, Chatterjee S, Dayeh MA, Muñoz-Jaramillo A, Desai MI, Limoli CL. Complex 33-beam simulated galactic cosmic radiation exposure impacts cognitive function and prefrontal cortex neurotransmitter networks in male mice. Nat Commun 2023; 14:7779. [PMID: 38012180 PMCID: PMC10682413 DOI: 10.1038/s41467-023-42173-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 09/28/2023] [Indexed: 11/29/2023] Open
Abstract
Astronauts will encounter extended exposure to galactic cosmic radiation (GCR) during deep space exploration, which could impair brain function. Here, we report that in male mice, acute or chronic GCR exposure did not modify reward sensitivity but did adversely affect attentional processes and increased reaction times. Potassium (K+)-stimulation in the prefrontal cortex (PFC) elevated dopamine (DA) but abolished temporal DA responsiveness after acute and chronic GCR exposure. Unlike acute GCR, chronic GCR increased levels of all other neurotransmitters, with differences evident between groups after higher K+-stimulation. Correlational and machine learning analysis showed that acute and chronic GCR exposure differentially reorganized the connection strength and causation of DA and other PFC neurotransmitter networks compared to controls which may explain space radiation-induced neurocognitive deficits.
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Affiliation(s)
- Rajeev I Desai
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, USA.
- Behavioral Biology Program, McLean Hospital, Belmont, MA, 02478, USA.
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA.
| | - Brian D Kangas
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, USA
- Behavioral Biology Program, McLean Hospital, Belmont, MA, 02478, USA
| | - Oanh T Luc
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, USA
- Behavioral Biology Program, McLean Hospital, Belmont, MA, 02478, USA
| | - Eleana Solakidou
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
- Medical School, University of Crete, Heraklion, Greece
| | - Evan C Smith
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Monica H Dawes
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, USA
- Behavioral Biology Program, McLean Hospital, Belmont, MA, 02478, USA
| | - Xiaoyu Ma
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | | | - Maher A Dayeh
- Southwest Research Institute, San Antonio, TX, 78238, USA
- University of San Antonio, San Antonio, TX, 78249, USA
| | | | - Mihir I Desai
- Southwest Research Institute, San Antonio, TX, 78238, USA
- University of San Antonio, San Antonio, TX, 78249, USA
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, Orange, CA, 92697, USA
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Yin Y, Liu J, Fan Q, Zhao S, Wu X, Wang J, Liu Y, Li Y, Lu W. Long-term spaceflight composite stress induces depression and cognitive impairment in astronauts-insights from neuroplasticity. Transl Psychiatry 2023; 13:342. [PMID: 37938258 PMCID: PMC10632511 DOI: 10.1038/s41398-023-02638-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 10/08/2023] [Accepted: 10/25/2023] [Indexed: 11/09/2023] Open
Abstract
The environment on the space station is quite unique compared to Earth, which is a composite of multiple stressors, such as microgravity, isolation, confinement, noise, circadian rhythm disturbance, and so on. During prolonged space missions, astronauts have to stay in such extreme environments for long periods, which could induce adverse effects on both their physical and mental health. In some circumstances, this kind of long-term spaceflight composite stress (LSCS) could also induce depression and cognitive impairment in various ways, including dysregulating the neuroplasticity of the brains of astronauts, which should be attached to great importance. Here, we have comprehensively reviewed the impact of individual and combined stressors on depression and cognitive function during long-term spaceflight, explained the underlying mechanisms of those effects from the perspective of neuroplasticity, and current countermeasures for mitigating these challenges. This review provides insights into LSCS and potential neuroplasticity mechanisms, current with potentially great impact for understanding and mitigating the mental health risks and traumas of career astronauts and space tourists.
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Affiliation(s)
- Yishu Yin
- School of Medicine and Health, Harbin Institute of Technology, Harbin, 150001, China
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, Harbin, 150001, China
| | - Junlian Liu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Quanchun Fan
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shuang Zhao
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xiaorui Wu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Jiaping Wang
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Yu Liu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Yongzhi Li
- China Astronaut Research and Training Center, Beijing, 100094, China.
| | - Weihong Lu
- School of Medicine and Health, Harbin Institute of Technology, Harbin, 150001, China.
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, Harbin, 150001, China.
- The Intelligent Equipment Research Center for the Exploitation of Characteristic Food & Medicine Resources, Chongqing Research Institute, Harbin Institute of Technology, Chongqing, 401135, China.
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Desorgher L, Stabilini A, Rostomyan T, Reggiani D, Hajdas W, Marcinkowski RM, Vozenin MC, Limoli CL, Yukihara EG, Bailat C. Dosimetry of the PIM1 Pion Beam at the Paul Scherrer Institute for Radiobiological Studies of Mice. Radiat Res 2023; 200:357-365. [PMID: 37702413 DOI: 10.1667/rade-23-00029.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/31/2023] [Indexed: 09/14/2023]
Abstract
Significant past work has identified unexpected risks of central nervous system (CNS) exposure to the space radiation environment, where long-lasting functional decrements have been associated with multiple ion species delivered at low doses and dose rates. As shielding is the only established intervention capable of limiting exposure to the dangerous radiation fields in space, the recent discovery that pions, emanating from regions of enhanced shielding, can contribute significantly to the total absorbed dose on a deep space mission poses additional concerns. As a prerequisite to biological studies evaluating pion dose equivalents for various CNS exposure scenarios of mice, a careful dosimetric validation study is required. Within our ultimate goal of evaluating the functional consequences of defined pion exposures to CNS functionality, we report in this article the detailed dosimetry of the PiMI pion beam line at the Paul Scherrer Institute, which was developed in support of radiobiological experiments. Beam profiles and contamination of the beam by protons, electrons, positrons and muons were characterized prior to the mice irradiations. The dose to the back and top of the mice was measured using thermoluminescent dosimeters (TLD) and optically simulated luminescence (OSL) to cross-validate the dosimetry results. Geant4 Monte Carlo simulations of radiation exposure of a mouse phantom in water by charged pions were also performed to quantify the difference between the absorbed dose from the OSL and TLD and the absorbed dose to water, using a simple model of the mouse brain. The absorbed dose measured by the OSL dosimeters and TLDs agreed within 5-10%. A 30% difference between the measured absorbed dose and the dose calculated by Geant4 in the dosimeters was obtained, probably due to the approximated Monte Carlo configuration compared to the experiment. A difference of 15-20% between the calculated absorbed dose to water at a 5 mm depth and in the passive dosimeters was obtained, suggesting the need for a correction factor of the measured dose to obtain the absorbed dose in the mouse brain. Finally, based on the comparison of the experimental data and the Monte Carlo calculations, we consider the dose measurement to be accurate to within 15-20%.
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Affiliation(s)
- L Desorgher
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Switzerland
| | - A Stabilini
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - T Rostomyan
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - D Reggiani
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - W Hajdas
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - R M Marcinkowski
- Paul Scherrer Institute (PSI), Villigen, Switzerland
- SE2S GMBH, Boppelsen ZH, Switzerland
| | - M-C Vozenin
- CHUV-Radiation-oncology Laboratory, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - C L Limoli
- Department of Radiation Oncology, University of California, Irvine, California
| | - E G Yukihara
- Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - C Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Switzerland
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Pusil S, Zegarra-Valdivia J, Cuesta P, Laohathai C, Cebolla AM, Haueisen J, Fiedler P, Funke M, Maestú F, Cheron G. Effects of spaceflight on the EEG alpha power and functional connectivity. Sci Rep 2023; 13:9489. [PMID: 37303002 DOI: 10.1038/s41598-023-34744-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/06/2023] [Indexed: 06/13/2023] Open
Abstract
Electroencephalography (EEG) can detect changes in cerebral activity during spaceflight. This study evaluates the effect of spaceflight on brain networks through analysis of the Default Mode Network (DMN)'s alpha frequency band power and functional connectivity (FC), and the persistence of these changes. Five astronauts' resting state EEGs under three conditions were analyzed (pre-flight, in-flight, and post-flight). DMN's alpha band power and FC were computed using eLORETA and phase-locking value. Eyes-opened (EO) and eyes-closed (EC) conditions were differentiated. We found a DMN alpha band power reduction during in-flight (EC: p < 0.001; EO: p < 0.05) and post-flight (EC: p < 0.001; EO: p < 0.01) when compared to pre-flight condition. FC strength decreased during in-flight (EC: p < 0.01; EO: p < 0.01) and post-flight (EC: ns; EO: p < 0.01) compared to pre-flight condition. The DMN alpha band power and FC strength reduction persisted until 20 days after landing. Spaceflight caused electrocerebral alterations that persisted after return to earth. Periodic assessment by EEG-derived DMN analysis has the potential to become a neurophysiologic marker of cerebral functional integrity during exploration missions to space.
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Affiliation(s)
- Sandra Pusil
- Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
| | - Jonathan Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Global Brain Health Institute (GBHI), University of California, San Francisco (UCSF), San Francisco, CA, USA
- Universidad Señor de Sipán, Chiclayo, Peru
| | - Pablo Cuesta
- Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Radiology, Rehabilitation, and Physiotherapy, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Ana Maria Cebolla
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, Brussels, Belgium
| | - Jens Haueisen
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Patrique Fiedler
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Michael Funke
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Fernando Maestú
- Center for Cognitive and Computational Neuroscience, Complutense University of Madrid, Madrid, Spain
- Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Department of Experimental Psychology, Universidad Complutense de Madrid, Madrid, Spain
- Instituto de Investigación Sanitario, Hospital Clínico San Carlos, Madrid, Spain
| | - Guy Cheron
- Laboratory of Neurophysiology and Movement Biomechanics, Université Libre de Bruxelles, Brussels, Belgium.
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Britten RA, Limoli CL. New Radiobiological Principles for the CNS Arising from Space Radiation Research. Life (Basel) 2023; 13:1293. [PMID: 37374076 DOI: 10.3390/life13061293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/17/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Traditionally, the brain has been regarded as a relatively insensitive late-reacting tissue, with radiologically detectable damage not being reported at doses < 60 Gy. When NASA proposed interplanetary exploration missions, it was required to conduct an intensive health and safety evaluation of cancer, cardiovascular, and cognitive risks associated with exposure to deep space radiation (SR). The SR dose that astronauts on a mission to Mars are predicted to receive is ~300 mGy. Even after correcting for the higher RBE of the SR particles, the biologically effective SR dose (<1 Gy) would still be 60-fold lower than the threshold dose for clinically detectable neurological damage. Unexpectedly, the NASA-funded research program has consistently reported that low (<250 mGy) doses of SR induce deficits in multiple cognitive functions. This review will discuss these findings and the radical paradigm shifts in radiobiological principles for the brain that were required in light of these findings. These included a shift from cell killing to loss of function models, an expansion of the critical brain regions for radiation-induced cognitive impediments, and the concept that the neuron may not be the sole critical target for neurocognitive impairment. The accrued information on how SR exposure impacts neurocognitive performance may provide new opportunities to reduce neurocognitive impairment in brain cancer patients.
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Affiliation(s)
- Richard A Britten
- EVMS Radiation Oncology, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Charles L Limoli
- Department Radiation Oncology, University of California-Irvine, Irvine, CA 92697, USA
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Faerman A, Clark JB, Sutton JP. Neuropsychological considerations for long-duration deep spaceflight. Front Physiol 2023; 14:1146096. [PMID: 37275233 PMCID: PMC10235498 DOI: 10.3389/fphys.2023.1146096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
The deep space environment far beyond low-Earth orbit (LEO) introduces multiple and simultaneous risks for the functioning and health of the central nervous system (CNS), which may impair astronauts' performance and wellbeing. As future deep space missions to Mars, moons, or asteroids will also exceed current LEO stay durations and are estimated to require up to 3 years, we review recent evidence with contemporary and historic spaceflight case studies addressing implications for long-duration missions. To highlight the need for specific further investigations, we provide neuropsychological considerations integrating cognitive and motor functions, neuroimaging, neurological biomarkers, behavior changes, and mood and affect to construct a multifactorial profile to explain performance variability, subjective experience, and potential risks. We discuss the importance of adopting a neuropsychological approach to long-duration deep spaceflight (LDDS) missions and draw specific recommendations for future research in space neuropsychology.
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Affiliation(s)
- Afik Faerman
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
| | - Jonathan B. Clark
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, United States
- Department of Neurology, Baylor College of Medicine, Houston, TX, United States
| | - Jeffrey P. Sutton
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, United States
- Translational Research Institute for Space Health, Baylor College of Medicine, Houston, TX, United States
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
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Homo sapiens—A Species Not Designed for Space Flight: Health Risks in Low Earth Orbit and Beyond, Including Potential Risks When Traveling beyond the Geomagnetic Field of Earth. Life (Basel) 2023; 13:life13030757. [PMID: 36983912 PMCID: PMC10051707 DOI: 10.3390/life13030757] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/03/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
Homo sapiens and their predecessors evolved in the context of the boundary conditions of Earth, including a 1 g gravity and a geomagnetic field (GMF). These variables, plus others, led to complex organisms that evolved under a defined set of conditions and define how humans will respond to space flight, a circumstance that could not have been anticipated by evolution. Over the past ~60 years, space flight and living in low Earth orbit (LEO) have revealed that astronauts are impacted to varying degrees by such new environments. In addition, it has been noted that astronauts are quite heterogeneous in their response patterns, indicating that such variation is either silent if one remained on Earth, or the heterogeneity unknowingly contributes to disease development during aging or in response to insults. With the planned mission to deep space, humans will now be exposed to further risks from radiation when traveling beyond the influence of the GMF, as well as other potential risks that are associated with the actual loss of the GMF on the astronauts, their microbiomes, and growing food sources. Experimental studies with model systems have revealed that hypogravity conditions can influence a variety biological and physiological systems, and thus the loss of the GMF may have unanticipated consequences to astronauts’ systems, such as those that are electrical in nature (i.e., the cardiovascular system and central neural systems). As astronauts have been shown to be heterogeneous in their responses to LEO, they may require personalized countermeasures, while others may not be good candidates for deep-space missions if effective countermeasures cannot be developed for long-duration missions. This review will discuss several of the physiological and neural systems that are affected and how the emerging variables may influence astronaut health and functioning.
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Towards sustainable human space exploration-priorities for radiation research to quantify and mitigate radiation risks. NPJ Microgravity 2023; 9:8. [PMID: 36707520 PMCID: PMC9883222 DOI: 10.1038/s41526-023-00262-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 01/20/2023] [Indexed: 01/28/2023] Open
Abstract
Human spaceflight is entering a new era of sustainable human space exploration. By 2030 humans will regularly fly to the Moon's orbit, return to the Moon's surface and preparations for crewed Mars missions will intensify. In planning these undertakings, several challenges will need to be addressed in order to ensure the safety of astronauts during their space travels. One of the important challenges to overcome, that could be a major showstopper of the space endeavor, is the exposure to the space radiation environment. There is an urgent need for quantifying, managing and limiting the detrimental health risks and electronics damage induced by space radiation exposure. Such risks raise key priority topics for space research programs. Risk limitation involves obtaining a better understanding of space weather phenomena and the complex radiation environment in spaceflight, as well as developing and applying accurate dosimetric instruments, understanding related short- and long-term health risks, and strategies for effective countermeasures to minimize both exposure to space radiation and the remaining effects post exposure. The ESA/SciSpacE Space Radiation White Paper identifies those topics and underlines priorities for future research and development, to enable safe human and robotic exploration of space beyond Low Earth Orbit.
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