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Neuroadaptation to Space Conditions-3

Neuroplasticity and Brain Health

Neuroadaptation 5

Image-1. Neuroplasticity and Brain Health (Created by AI)

Space Flight-Induced Neuroplasticity in Humans and Measurement with MRI

A study investigating changes in functional brain connectivity following prolonged spaceflight using functional MRI (fMRI) focused on changes in brain connectivity patterns following space missions and provided data on how the brain’s functional networks adapt to the challenges of spaceflight.

Using fMRI researchers were able to detect neural connectivity changes associated with space travel and shed light on the neuroplastic changes that occur in astronauts’ brains during and after space missions.

Neuroplasticity During Space Flight

  • Structural Changes : MRI studies have shown significant structural changes in the brains of astronauts after space missions. These include changes in cortical thickness ventricular enlargement and changes in brain position due to fluid redistribution.
  • Functional Changes : Functional MRI (fMRI) has revealed changes in brain activity patterns particularly in areas associated with sensory-motor functions and spatial orientation. These changes reflect the brain’s adaptation to microgravity conditions.
  • White Matter Integrity : Diffusion tensor imaging (DTI) a type of MRI has detected microstructural changes in white matter tracts. These changes suggest alterations in connectivity and communication between different brain regions.

Measurement with MRI

  • Cortical Thickness : By measuring the thickness of the cerebral cortex with MRI scans we provide information on structural changes over time. Spaceflight-induced cortical thinning or thickening may be indicative of neuroplastic adaptation to microgravity.
  • Ventricular Volume : MRI can measure changes in ventricular volume which is usually increased due to fluid changes in microgravity. Enlarged ventricles are indicative of altered CSF dynamics and intracranial pressure.
  • Brain Position : Structural MRI can detect changes in brain position within the skull a common adaptation to fluid redistribution in space.
    Importance of Understanding the Impact of Long Duration Spaceflight on Spatial Cognition and Neural Circuits

Impact on Spatial Cognition

  • Navigation and Orientation: Microgravity disrupts the vestibular system which is crucial for balance and spatial orientation. Astronauts often experience disorientation and difficulties in spatial navigation affecting their ability to move efficiently within the spacecraft.
  • Memory and Learning : Prolonged exposure to space conditions can impair spatial memory and learning. Studies have shown that astronauts may have difficulty with tasks that require the recall of spatial information and the creation of new spatial memories.

Nerve Circuit Changes

  • Hippocampal Plasticity : The hippocampus a brain region integral to spatial memory and navigation undergoes significant changes during spaceflight. Structural MRI studies have observed hippocampal volume changes that may be associated with altered spatial cognition.
  • Functional Connectivity : fMRI studies reveal changes in functional connectivity between brain regions involved in spatial processing. These changes suggest that the brain reorganizes neural networks to adapt to changing sensory inputs in microgravity.

Importance for Space Missions

  • Mission Performance : Understanding how spaceflight affects spatial cognition is crucial for mission success. Impairment of spatial abilities can hinder astronauts’ performance in navigation docking procedures and off-board activities.
  • Education and Countermeasures : Data on neuroplasticity and spatial cognition can inform the development of training programs and countermeasures. Cognitive training virtual reality simulations and neurofeedback techniques can help mitigate the negative effects of microgravity on spatial abilities.
  • Health and Safety : Maintaining optimal brain health is vital to the overall well-being of astronauts. Addressing the cognitive and neural effects of spaceflight ensures that astronauts can perform their missions effectively and return to Earth without long-term cognitive impairments.

Future Research Directions and Mitigation Strategies

FIG. 6-CREATED BY AI – Future Research Directions and Mitigation Strategies

Expert Consensus on Future Research Directions

A team of experts on the effects of the spaceflight environment on the brain and eye (Spaceflight-Associated Neuro-ocular Syndrome-SANS) was convened by NASA and ESA to review spaceflight-induced structural and functional changes in the human brain and eye and the interactions between the two; and to identify critical future research directions in this area to help define risk and identify possible countermeasures and strategies to mitigate spaceflight-induced brain and eye changes. Aiming to identify risks and develop mitigation strategies for spaceflight-induced neuro-structural changes the team achieved a broad expert consensus on future research focuses. Key areas of focus include:

Longitudinal Studies

  • Conducting long-term studies following astronauts before during and after space missions to understand the progression and persistence of neurostructural changes.
  • Using advanced neuroimaging techniques to track changes in brain structure and function over long periods of time.

Individual Variability

  • Investigating individual differences in susceptibility to neuro-structural changes and cognitive impairment. This includes the study of genetic physiological and psychological factors that may influence an astronaut’s endurance or sensitivity.
  • Development of personalized countermeasures according to individual needs based on specific risk profiles.

Neuroprotective Interventions

  • Investigating pharmacological and non-pharmacological interventions that can protect the brain from the adverse effects of microgravity. This includes investigating the effectiveness of neuroprotective drugs cognitive training programs and physical exercise regimes.
  • Investigating the potential benefits of artificial gravity environments or intermittent exposure to gravitational forces as a means of mitigating neurostructural changes.

Sensory Motor Function

  • Investigating the effects of microgravity on sensory-motor function and developing strategies to improve motor control and spatial orientation. This includes the study of the vestibular system and its adaptation to the space environment.
  • Implementation of training programs that simulate space conditions to improve astronauts’ ability to adapt to and recover from sensory-motor disruptions.

Multidisciplinary Approaches

  • Foster collaborative research efforts that combine neuroscience psychology medicine and engineering to develop comprehensive solutions to the challenges posed by spaceflight.
  • Using the latest technologies such as virtual reality robotics and neuro feedback to create innovative training and rehabilitation tools.

There is a Need for Continued Research Using Blood-Based Biomarkers!

Ongoing research using blood-based biomarkers to identify the neurological consequences of spaceflight is growing in importance. Blood biomarkers can provide valuable insights into the biological processes underlying neuro-structural changes and cognitive disorders.

Biomarker Discovery

  • Identifying specific biomarkers that reflect changes in brain health and cognitive function during and after space missions. This includes markers of inflammation oxidative stress neurodegeneration and neuroplasticity.
    Develop sensitive and specific assays to measure these biomarkers in blood samples collected from astronauts.

Monitoring Brain Health

  • Using biomarkers to monitor the impact of spaceflight on brain health in real time. This allows early detection of potential problems and timely intervention to prevent long-term damage.
  • Correlate biomarker levels with neuroimaging findings and cognitive performance tests to verify their relevance and accuracy.

Predictive Models

  • Building predictive models that use biomarker data to assess the risk of neuro-structural changes and cognitive impairment. These models can help identify astronauts at higher risk and guide the development of personalized countermeasures.
  • Integrating biomarker data with other physiological and environmental variables to create comprehensive risk assessment tools.

Therapeutic Objectives

  • Investigating biomarkers as potential therapeutic targets for neuroprotection and cognitive enhancement. This includes examining the effects of interventions on biomarker levels and associated outcomes.
  • Investigating the use of biomarkers to evaluate the efficacy of neuroprotective strategies and optimize treatment protocols.

Conclusion

Neuroadaptation to spaceflight is a complex and dynamic process involving the brain’s ability to adapt to the challenges of the space environment. Through the synthesis of research findings several important points about neuroadaptation emerge:

    • Neuroplasticity : The brain exhibits extraordinary neuroplasticity in response to microgravity undergoing structural functional and neurochemical changes to adapt to the absence of gravitational cues. These adaptations include changes in brain structure connectivity neurotransmitter systems and cognitive functions.
    • Structural Changes : Neuroimaging studies reveal changes in brain position changes in gray and white matter volumes changes in cortical thickness and enlargement of the ventricles due to fluid redistribution. These structural changes reflect the brain’s adaptive response to microgravity-induced changes in sensory inputs and fluid dynamics.
    • Functional Changes : Changes in brain activity patterns particularly in regions related to sensory-motor processing spatial cognition attention and memory highlight the brain’s efforts to rewire neural circuits to optimize performance in the space environment.
    • Cognitive Effects : Spaceflight-induced neuroadaptation can lead to cognitive changes including decreases in working memory attention visual-motor coordination and spatial cognition. These cognitive effects emphasize the importance of understanding the neural mechanisms underlying cognitive performance in space.

Ongoing research to understand and mitigate the effects of spaceflight on the human brain is crucial for several reasons:

  • Mission Success and Safety : Ensuring the cognitive health and performance of astronauts is essential for mission success and safety. Cognitive impairments in space can compromise astronauts’ ability to perform critical tasks potentially jeopardizing mission objectives and crew well-being.
  • Long-Term Health: Addressing the neurological consequences of spaceflight is vital to protecting the long-term brain health of astronauts. Prolonged exposure to microgravity can pose a risk for neurodegeneration cognitive decline and mental health disorders and requires proactive measures to mitigate these effects.
  • Countermeasure Development : Ongoing research is facilitating the development of effective countermeasures to protect against neurostructural changes and cognitive impairments in space. This includes exploration of pharmacological interventions cognitive training programs sensory stimulation techniques and personalized approaches tailored to the needs of individual astronauts.
  • Advancing Neuroscience: Space exploration serves as a unique opportunity to deepen our understanding of brain function and neuroplasticity in extreme environments. Insights from spaceflight neuroadaptation studies could have broader implications for terrestrial applications including rehabilitation therapies neurorehabilitation and aging-related cognitive decline.

 

In our next article we will look at the details of the studies that inspired this article and are driving space neuroscience data. Until our next meeting take care of your ‘nerves’!

Sections:

References

  • Jillings, S., Ombergen, A., Tomilovskaya, E., Rumshiskaya, A., Litvinova, L., Nosikova, I., … & Jeurissen, B. (2020). Macro- and microstructural changes in cosmonauts’ brains after long-duration spaceflight. Science Advances, 6(36). https://doi.org/10.1126/sciadv.aaz9488
  • Roy-O’Reilly, M., Mulavara, A., & Williams, T. (2021). A review of alterations to the brain during spaceflight and the potential relevance to crew in long-duration space exploration. NPJ Microgravity, 7(1). https://doi.org/10.1038/s41526-021-00133-z
  • Lee, J., Koppelmans, V., Riascos, R., Hasan, K., Pasternak, O., Mulavara, A., … & Seidler, R. (2019). Spaceflight-associated brain white matter microstructural changes and intracranial fluid redistribution. Jama Neurology, 76(4), 412. https://doi.org/10.1001/jamaneurol.2018.4882
  • Salazar, A., Hupfeld, K., Lee, J., Beltran, N., Kofman, I., Dios, Y., … & Seidler, R. (2020). Neural working memory changes during a spaceflight analog with elevated carbon dioxide: a pilot study. Frontiers in Systems Neuroscience, 14. https://doi.org/10.3389/fnsys.2020.00048
  • Peng, Y., Koppelmans, V., Reuter‐Lorenz, P., Dios, Y., Gadd, N., Wood, S., … & Seidler, R. (2016). Increased brain activation for dual tasking with 70-days head-down bed rest. Frontiers in Systems Neuroscience, 10. https://doi.org/10.3389/fnsys.2016.00071
  • Ombergen, A., Laureys, S., Sunaert, S., Tomilovskaya, E., Parizel, P., & Wuyts, F. (2017). Spaceflight-induced neuroplasticity in humans as measured by mri: what do we know so far?. NPJ Microgravity, 3(1). https://doi.org/10.1038/s41526-016-0010-8
  • Stahn, A. and Kühn, S. (2021). Brains in space: the importance of understanding the impact of long-duration spaceflight on spatial cognition and its neural circuitry. Cognitive Processing, 22(S1), 105-114. https://doi.org/10.1007/s10339-021-01050-5
  • Seidler, R., Stern, C., Basner, M., Stahn, A., Wuyts, F., & Eulenburg, P. (2022). Future research directions to identify risks and mitigation strategies for neurostructural, ocular, and behavioral changes induced by human spaceflight: a nasa-esa expert group consensus report. Frontiers in Neural Circuits, 16.
  • https://doi.org/10.3389/fncir.2022.876789
  • Eulenburg, P. (2022). Blood biomarkers may have found a new frontier in spaceflight—reply. Jama Neurology, 79(6), 632.
  • https://doi.org/10.1001/jamaneurol.2022.0673

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Doktor, MoEP Uzay Nörobilim Takımı (NEUR-PACE) üyesi ve yazarı. (Doctor - MoEP Space Neuroscience Team - NEUR-PACE crew and author)

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