Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study
Astronauts return to Earth from spaceflight missions with impaired mobility and balance; recovery can last weeks postflight. This is due in large part to the altered vestibular signaling and sensory reweighting that occurs in microgravity. The neural mechanisms of spaceflight-induced vestibular chan...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-01-01
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| Series: | Frontiers in Systems Neuroscience |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fnsys.2019.00080/full |
| _version_ | 1818217291253284864 |
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| author | Kathleen E. Hupfeld Jessica K. Lee Nichole E. Gadd Igor S. Kofman Yiri E. De Dios Jacob J. Bloomberg Ajitkumar P. Mulavara Rachael D. Seidler Rachael D. Seidler |
| author_facet | Kathleen E. Hupfeld Jessica K. Lee Nichole E. Gadd Igor S. Kofman Yiri E. De Dios Jacob J. Bloomberg Ajitkumar P. Mulavara Rachael D. Seidler Rachael D. Seidler |
| author_sort | Kathleen E. Hupfeld |
| collection | DOAJ |
| description | Astronauts return to Earth from spaceflight missions with impaired mobility and balance; recovery can last weeks postflight. This is due in large part to the altered vestibular signaling and sensory reweighting that occurs in microgravity. The neural mechanisms of spaceflight-induced vestibular changes are not well understood. Head-down-tilt bed rest (HDBR) is a common spaceflight analog environment that allows for study of body unloading, fluid shifts, and other consequences of spaceflight. Subjects in this context still show vestibular changes despite being in Earth’s gravitational environment, potentially due to sensory reweighting. Previously, we found evidence of sensory reweighting and reduced neural efficiency for vestibular processing in subjects who underwent a 70-day HDBR intervention. Here we extend this work by evaluating the impact of HDBR paired with elevated carbon dioxide (CO2) to mimic International Space Station conditions on vestibular neural processing. Eleven participants (6 males, 34 ± 8 years) completed 30 days of HDBR combined with 0.5% atmospheric CO2 (HDBR + CO2). Participants underwent six functional magnetic resonance imaging (fMRI) sessions pre-, during, and post- HDBR + CO2 while we measured brain activity in response to pneumatic skull taps (a validated method of vestibular stimulation). We also measured mobility and balance performance several times before and after the intervention. We found support for adaptive neural changes within the vestibular system during bed rest that subsequently recovered in several cortical and cerebellar regions. Further, there were multiple brain regions where greater pre- to post- deactivation was associated with reduced pre- to post- balance declines. That is, increased deactivation of certain brain regions associated with better balance post-HDBR + CO2. We also found that, compared to HDBR alone (n = 13 males; 29 ± 3 years) HDBR + CO2 is associated with greater increases in activation of multiple frontal, parietal, and temporal regions during vestibular stimulation. This suggests interactive or additive effects of bed rest and elevated CO2. Finally, we found stronger correlations between pre- to post- HDBR + CO2 brain changes and dependence on the visual system during balance for subjects who developed signs of Spaceflight-Associated Neuro-ocular Syndrome (SANS). Together, these findings have clear implications for understanding the neural mechanisms of bed rest and spaceflight-related changes in vestibular processing, as well as adaptation to altered sensory inputs. |
| first_indexed | 2024-12-12T07:05:32Z |
| format | Article |
| id | doaj.art-83b04955f2b74586a2c520c7d5ab1c8c |
| institution | Directory Open Access Journal |
| issn | 1662-5137 |
| language | English |
| last_indexed | 2024-12-12T07:05:32Z |
| publishDate | 2020-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Systems Neuroscience |
| spelling | doaj.art-83b04955f2b74586a2c520c7d5ab1c8c2022-12-22T00:33:44ZengFrontiers Media S.A.Frontiers in Systems Neuroscience1662-51372020-01-011310.3389/fnsys.2019.00080498855Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot StudyKathleen E. Hupfeld0Jessica K. Lee1Nichole E. Gadd2Igor S. Kofman3Yiri E. De Dios4Jacob J. Bloomberg5Ajitkumar P. Mulavara6Rachael D. Seidler7Rachael D. Seidler8Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United StatesGerman Aerospace Center, Institute of Aerospace Medicine, Cologne, GermanyKBR, Houston, TX, United StatesKBR, Houston, TX, United StatesKBR, Houston, TX, United StatesNASA Johnson Space Center, Houston, TX, United StatesKBR, Houston, TX, United StatesDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United StatesDepartment of Neurology, University of Florida, Gainesville, FL, United StatesAstronauts return to Earth from spaceflight missions with impaired mobility and balance; recovery can last weeks postflight. This is due in large part to the altered vestibular signaling and sensory reweighting that occurs in microgravity. The neural mechanisms of spaceflight-induced vestibular changes are not well understood. Head-down-tilt bed rest (HDBR) is a common spaceflight analog environment that allows for study of body unloading, fluid shifts, and other consequences of spaceflight. Subjects in this context still show vestibular changes despite being in Earth’s gravitational environment, potentially due to sensory reweighting. Previously, we found evidence of sensory reweighting and reduced neural efficiency for vestibular processing in subjects who underwent a 70-day HDBR intervention. Here we extend this work by evaluating the impact of HDBR paired with elevated carbon dioxide (CO2) to mimic International Space Station conditions on vestibular neural processing. Eleven participants (6 males, 34 ± 8 years) completed 30 days of HDBR combined with 0.5% atmospheric CO2 (HDBR + CO2). Participants underwent six functional magnetic resonance imaging (fMRI) sessions pre-, during, and post- HDBR + CO2 while we measured brain activity in response to pneumatic skull taps (a validated method of vestibular stimulation). We also measured mobility and balance performance several times before and after the intervention. We found support for adaptive neural changes within the vestibular system during bed rest that subsequently recovered in several cortical and cerebellar regions. Further, there were multiple brain regions where greater pre- to post- deactivation was associated with reduced pre- to post- balance declines. That is, increased deactivation of certain brain regions associated with better balance post-HDBR + CO2. We also found that, compared to HDBR alone (n = 13 males; 29 ± 3 years) HDBR + CO2 is associated with greater increases in activation of multiple frontal, parietal, and temporal regions during vestibular stimulation. This suggests interactive or additive effects of bed rest and elevated CO2. Finally, we found stronger correlations between pre- to post- HDBR + CO2 brain changes and dependence on the visual system during balance for subjects who developed signs of Spaceflight-Associated Neuro-ocular Syndrome (SANS). Together, these findings have clear implications for understanding the neural mechanisms of bed rest and spaceflight-related changes in vestibular processing, as well as adaptation to altered sensory inputs.https://www.frontiersin.org/article/10.3389/fnsys.2019.00080/fullvestibularfMRIhead-down-tilt bed rest (HDBR)carbon dioxide (CO2)spaceflight |
| spellingShingle | Kathleen E. Hupfeld Jessica K. Lee Nichole E. Gadd Igor S. Kofman Yiri E. De Dios Jacob J. Bloomberg Ajitkumar P. Mulavara Rachael D. Seidler Rachael D. Seidler Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study Frontiers in Systems Neuroscience vestibular fMRI head-down-tilt bed rest (HDBR) carbon dioxide (CO2) spaceflight |
| title | Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study |
| title_full | Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study |
| title_fullStr | Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study |
| title_full_unstemmed | Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study |
| title_short | Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study |
| title_sort | neural correlates of vestibular processing during a spaceflight analog with elevated carbon dioxide co2 a pilot study |
| topic | vestibular fMRI head-down-tilt bed rest (HDBR) carbon dioxide (CO2) spaceflight |
| url | https://www.frontiersin.org/article/10.3389/fnsys.2019.00080/full |
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