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Tays GD, Hupfeld KE, McGregor HR, Beltran NE, De Dios YE, Mulder E, Bloomberg JJ, Mulavara AP, Wood SJ, Seidler RD. Daily artificial gravity partially mitigates vestibular processing changes associated with head-down tilt bedrest. NPJ Microgravity 2024; 10:27. [PMID: 38472244 PMCID: PMC10933323 DOI: 10.1038/s41526-024-00367-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
Microgravity alters vestibular signaling and reduces body loading, driving sensory reweighting. The unloading effects can be modelled using head-down tilt bedrest (HDT). Artificial gravity (AG) has been hypothesized to serve as an integrated countermeasure for the declines associated with HDT and spaceflight. Here, we examined the efficacy of 30 min of daily AG to counteract brain and behavior changes from 60 days of HDT. Two groups received 30 min of AG delivered via short-arm centrifuge daily (n = 8 per condition), either in one continuous bout, or in 6 bouts of 5 min. To improve statistical power, we combined these groups (AG; n = 16). Another group served as controls in HDT with no AG (CTRL; n = 8). We examined how HDT and AG affect vestibular processing by collecting fMRI scans during vestibular stimulation. We collected these data prior to, during, and post-HDT. We assessed brain activation initially in 12 regions of interest (ROIs) and then conducted an exploratory whole brain analysis. The AG group showed no changes in activation during vestibular stimulation in a cerebellar ROI, whereas the CTRL group showed decreased activation specific to HDT. Those that received AG and showed little pre- to post-HDT changes in left vestibular cortex activation had better post-HDT balance performance. Whole brain analyses identified increased pre- to during-HDT activation in CTRLs in the right precentral gyrus and right inferior frontal gyrus, whereas AG maintained pre-HDT activation levels. These results indicate that AG could mitigate activation changes in vestibular processing that is associated with better balance performance.
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Affiliation(s)
- G D Tays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - K E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - H R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | | | | | - E Mulder
- German Aerospace Center (DLR), Cologne, Germany
| | | | | | - S J Wood
- NASA Johnson Space Center, Houston, TX, USA
| | - R D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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Seidler R, Tays G, Hupfeld K, McGregor H, Beltran N, de Dios Y, Mulder E, Bloomberg J, Mulavara A, Wood S. Daily Artificial Gravity Partially Mitigates Vestibular Processing Changes Associated with Head-down Tilt Bedrest. RESEARCH SQUARE 2023:rs.3.rs-3157785. [PMID: 37502989 PMCID: PMC10371135 DOI: 10.21203/rs.3.rs-3157785/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Microgravity alters vestibular signaling and reduces body loading, driving sensory reweighting and adaptation. The unloading effects can be modelled using head down tilt bedrest (HDT). Artificial gravity (AG) has been hypothesized to serve as an integrated countermeasure for the physiological declines associated with HDT and spaceflight. Here, we examined the efficacy of 30 minutes of daily AG to counteract brain and behavior changes that arise from 60 days of HDT. One group of participants received 30 minutes of AG daily (AG; n = 16) while in HDT, and another group served as controls, spending 60 days in HDT bedrest with no AG (CTRL; n = 8). We examined how HDT and AG affect vestibular processing by collecting fMRI scans from participants as they received vestibular stimulation. We collected these data prior to, during (2x), and post HDT. We assessed brain activation initially in 10 regions of interest (ROIs) and then conducted an exploratory whole brain analysis. The AG group showed no changes in brain activation during vestibular stimulation in a cerebellar ROI, whereas the CTRL group showed decreased cerebellar activation specific to the HDT phase. Additionally, those that received AG and showed little pre- to post-bed rest changes in left OP2 activation during HDT had better post-HDT balance performance. Exploratory whole brain analyses identified increased pre- to during-HDT activation in the CTRL group in the right precentral gyrus and the right inferior frontal gyrus specific to HDT, where the AG group maintained pre-HDT activation levels. Together, these results indicate that AG could mitigate brain activation changes in vestibular processing in a manner that is associated with better balance performance after HDT.
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3
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Tays GD, Hupfeld KE, McGregor HR, Beltran NE, Kofman IS, De Dios YE, Mulder ER, Bloomberg JJ, Mulavara AP, Wood SJ, Seidler RD. Daily artificial gravity is associated with greater neural efficiency during sensorimotor adaptation. Cereb Cortex 2023; 33:8011-8023. [PMID: 36958815 PMCID: PMC10267627 DOI: 10.1093/cercor/bhad094] [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: 10/27/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/25/2023] Open
Abstract
Altered vestibular signaling and body unloading in microgravity results in sensory reweighting and adaptation. Microgravity effects are well-replicated in head-down tilt bed rest (HDBR). Artificial gravity (AG) is a potential countermeasure to mitigate the effects of microgravity on human physiology and performance. We examined the effectiveness of daily AG for mitigating brain and/or behavioral changes in 60 days of HDBR. One group received AG for 30 minutes daily (AG; n = 16) and a control group spent the same time in HDBR but received no AG (CTRL; n = 8). All participants performed a sensorimotor adaptation task five times during fMRI scanning: twice prior to HDBR, twice during HDBR, and once following HDBR. The AG group showed similar behavioral adaptation effects compared with the CTRLs. We identified decreased brain activation in the AG group from pre to late HDBR in the cerebellum for the task baseline portion and in the thalamus, calcarine, cuneus, premotor cortices, and superior frontal gyrus in the AG group during the early adaptation phase. The two groups also exhibited differential brain-behavior correlations. Together, these results suggest that AG may result in a reduced recruitment of brain activity for basic motor processes and sensorimotor adaptation. These effects may stem from the somatosensory and vestibular stimulation that occur with AG.
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Affiliation(s)
- Grant D Tays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32603, USA
| | - Kathleen E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32603, USA
| | - Heather R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32603, USA
| | | | | | | | | | | | | | - Scott J Wood
- NASA Johnson Space Center, Houston, TX 77058, USA
| | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32603, USA
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32603, USA
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Barkaszi I, Ehmann B, Tölgyesi B, Balázs L, Altbäcker A. Are head-down tilt bedrest studies capturing the true nature of spaceflight-induced cognitive changes? A review. Front Physiol 2022; 13:1008508. [PMID: 36582360 PMCID: PMC9792854 DOI: 10.3389/fphys.2022.1008508] [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: 07/31/2022] [Accepted: 10/26/2022] [Indexed: 12/15/2022] Open
Abstract
Although a number of studies have examined cognitive functions in space, the reasons behind the observed changes described by space research and anecdotal reports have not yet been elucidated. A potential source of cognitive changes is the cephalad fluid shift in the body caused by the lack of hydrostatic pressure under microgravity. These alterations can be modeled under terrestrial conditions using ground-based studies, such as head-down tilt bedrest (HDBR). In this review, we compare the results of the space and HDBR cognitive research. Results for baseline and in-flight/in-HDBR comparisons, and for baseline and post-flight/post-HDBR comparisons are detailed regarding sensorimotor skills, time estimation, attention, psychomotor speed, memory, executive functions, reasoning, mathematical processing, and cognitive processing of emotional stimuli. Beyond behavioral performance, results regarding brain electrical activity during simulated and real microgravity environments are also discussed. Finally, we highlight the research gaps and suggest future directions.
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Affiliation(s)
- Irén Barkaszi
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
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5
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Seidler RD, Stern C, Basner M, Stahn AC, Wuyts FL, zu Eulenburg P. 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. Front Neural Circuits 2022; 16:876789. [PMID: 35991346 PMCID: PMC9387435 DOI: 10.3389/fncir.2022.876789] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
A team of experts on the effects of the spaceflight environment on the brain and eye (SANS: Spaceflight-Associated Neuro-ocular Syndrome) was convened by NASA and ESA to (1) review spaceflight-associated structural and functional changes of the human brain and eye, and any interactions between the two; and (2) identify critical future research directions in this area to help characterize the risk and identify possible countermeasures and strategies to mitigate the spaceflight-induced brain and eye alterations. The experts identified 14 critical future research directions that would substantially advance our knowledge of the effects of spending prolonged periods of time in the spaceflight environment on SANS, as well as brain structure and function. They used a paired comparison approach to rank the relative importance of these 14 recommendations, which are discussed in detail in the main report and are summarized briefly below.
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Affiliation(s)
- Rachael D. Seidler
- Department of Applied Physiology & Kinesiology, Health and Human Performance, University of Florida, Gainesville, FL, United States
| | - Claudia Stern
- Department of Clinical Aerospace Medicine, German Aerospace Center (DLR) and ISS Operations and Astronauts Group, European Astronaut Centre, European Space Agency (ESA), Cologne, Germany
- *Correspondence: Claudia Stern,
| | - Mathias Basner
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Alexander C. Stahn
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Floris L. Wuyts
- Department of Physics, University of Antwerp, Antwerp, Belgium
- Laboratory for Equilibrium Investigations and Aerospace (LEIA), Antwerp, Belgium
| | - Peter zu Eulenburg
- German Vertigo and Balance Center, University Hospital, Ludwig-Maximilians-Universität München (LMU), Munich, Germany
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Koppelmans V, Mulavara AP, Seidler RD, De Dios YE, Bloomberg JJ, Wood SJ. Cortical thickness of primary motor and vestibular brain regions predicts recovery from fall and balance directly after spaceflight. Brain Struct Funct 2022; 227:2073-2086. [PMID: 35469104 DOI: 10.1007/s00429-022-02492-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/30/2022] [Indexed: 01/02/2023]
Abstract
Motor adaptations to the microgravity environment during spaceflight allow astronauts to perform adequately in this unique environment. Upon return to Earth, this adaptation is no longer appropriate and can be disruptive for mission critical tasks. Here, we measured if metrics derived from MRI scans collected from astronauts can predict motor performance post-flight. Structural and diffusion MRI scans from 14 astronauts collected before launch, and motor measures (balance performance, speed of recovery from fall, and tandem walk step accuracy) collected pre-flight and post-flight were analyzed. Regional measures of gray matter volume (motor cortex, paracentral lobule, cerebellum), myelin density (motor cortex, paracentral lobule, corticospinal tract), and white matter microstructure (corticospinal tract) were derived as a-priori predictors. Additional whole-brain analyses of cortical thickness, cerebellar gray matter, and cortical myelin were also tested for associations with post-flight and pre-to-post-flight motor performance. The pre-selected regional measures were not significantly associated with motor behavior. However, whole-brain analyses showed that paracentral and precentral gyri thickness significantly predicted recovery from fall post-spaceflight. Thickness of vestibular and sensorimotor regions, including the posterior insula and the superior temporal gyrus, predicted balance performance post-flight and pre-to-post-flight decrements. Greater cortical thickness pre-flight predicted better performance post-flight. Regional thickness of somatosensory, motor, and vestibular brain regions has some predictive value for post-flight motor performance in astronauts, which may be used for the identification of training and countermeasure strategies targeted for maintaining operational task performance.
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Affiliation(s)
| | | | - Rachael D Seidler
- Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | | | - Jacob J Bloomberg
- National Aeronautics and Space Administration Johnson Space Center, Houston, TX, USA
| | - Scott J Wood
- National Aeronautics and Space Administration Johnson Space Center, Houston, TX, USA
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7
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Nosikova I, Riabova A, Amirova L, Kitov V, Tomilovskaya E. NAIAD-2020: Characteristics of Motor Evoked Potentials After 3-Day Exposure to Dry Immersion in Women. Front Hum Neurosci 2021; 15:753259. [PMID: 34924980 PMCID: PMC8671694 DOI: 10.3389/fnhum.2021.753259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
As female astronauts participate in space flight more and more frequently, there is a demand for research on how the female body adapts to the microgravity environment. In particular, there is very little research on how the neuromuscular system reacts to gravitational unloading in women. We aimed to estimate changes in motor evoked potentials (MEPs) in the lower leg muscles in women after 3-day exposure to Dry Immersion (DI), which is one of the most widely used ground models of microgravity. Six healthy female volunteers (mean age 30.17 ± 5.5 years) with a natural menstrual cycle participated in this experiment. MEPs were recorded from the gastrocnemius and soleus muscles twice before DI, on the day of DI completion, and 3 days after DI, during the recovery period. To evoke motor responses, transcranial and trans-spinal magnetic stimulation was applied. We showed that changes in MEP characteristics after DI exposure were different depending on the stimulation site, but were similar for both muscles. For trans-spinal stimulation, MEP thresholds decreased compared to baseline values, and amplitudes, on the contrary, increased, resembling the phenomenon of hypogravitational hyperreflexia. This finding is in line with data observed in other experiments on both male and female participants. MEPs to transcranial stimulation had an opposing dynamic, which may have resulted from the small group size and large inter-subject variability, or from hormonal fluctuations during the menstrual cycle. Central motor conduction time remained unchanged, suggesting that pyramidal tract conductibility was not affected by DI exposure. More research is needed to explore the underlying mechanisms.
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8
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Mhatre SD, Iyer J, Puukila S, Paul AM, Tahimic CGT, Rubinstein L, Lowe M, Alwood JS, Sowa MB, Bhattacharya S, Globus RK, Ronca AE. Neuro-consequences of the spaceflight environment. Neurosci Biobehav Rev 2021; 132:908-935. [PMID: 34767877 DOI: 10.1016/j.neubiorev.2021.09.055] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 08/03/2021] [Accepted: 09/28/2021] [Indexed: 12/17/2022]
Abstract
As human space exploration advances to establish a permanent presence beyond the Low Earth Orbit (LEO) with NASA's Artemis mission, researchers are striving to understand and address the health challenges of living and working in the spaceflight environment. Exposure to ionizing radiation, microgravity, isolation and other spaceflight hazards pose significant risks to astronauts. Determining neurobiological and neurobehavioral responses, understanding physiological responses under Central Nervous System (CNS) control, and identifying putative mechanisms to inform countermeasure development are critically important to ensuring brain and behavioral health of crew on long duration missions. Here we provide a detailed and comprehensive review of the effects of spaceflight and of ground-based spaceflight analogs, including simulated weightlessness, social isolation, and ionizing radiation on humans and animals. Further, we discuss dietary and non-dietary countermeasures including artificial gravity and antioxidants, among others. Significant future work is needed to ensure that neural, sensorimotor, cognitive and other physiological functions are maintained during extended deep space missions to avoid potentially catastrophic health and safety outcomes.
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Affiliation(s)
- Siddhita D Mhatre
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; KBR, Houston, TX, 77002, USA; COSMIAC Research Center, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Janani Iyer
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Universities Space Research Association, Columbia, MD, 21046, USA
| | - Stephanie Puukila
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Universities Space Research Association, Columbia, MD, 21046, USA; Flinders University, Adelaide, Australia
| | - Amber M Paul
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Universities Space Research Association, Columbia, MD, 21046, USA
| | - Candice G T Tahimic
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; KBR, Houston, TX, 77002, USA; Department of Biology, University of North Florida, Jacksonville, FL, 32224, USA
| | - Linda Rubinstein
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Universities Space Research Association, Columbia, MD, 21046, USA
| | - Moniece Lowe
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Blue Marble Space Institute of Science, Seattle, WA, 98154, USA
| | - Joshua S Alwood
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Marianne B Sowa
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Sharmila Bhattacharya
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - Ruth K Globus
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA
| | - April E Ronca
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, 94035, USA; Wake Forest Medical School, Winston-Salem, NC, 27101, USA.
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9
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Macaulay TR, Peters BT, Wood SJ, Clément GR, Oddsson L, Bloomberg JJ. Developing Proprioceptive Countermeasures to Mitigate Postural and Locomotor Control Deficits After Long-Duration Spaceflight. Front Syst Neurosci 2021; 15:658985. [PMID: 33986648 PMCID: PMC8111171 DOI: 10.3389/fnsys.2021.658985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/06/2021] [Indexed: 12/16/2022] Open
Abstract
Astronauts experience post-flight disturbances in postural and locomotor control due to sensorimotor adaptations during spaceflight. These alterations may have adverse consequences if a rapid egress is required after landing. Although current exercise protocols can effectively mitigate cardiovascular and muscular deconditioning, the benefits to post-flight sensorimotor dysfunction are limited. Furthermore, some exercise capabilities like treadmill running are currently not feasible on exploration spaceflight vehicles. Thus, new in-flight operational countermeasures are needed to mitigate postural and locomotor control deficits after exploration missions. Data from spaceflight and from analog studies collectively suggest that body unloading decreases the utilization of proprioceptive input, and this adaptation strongly contributes to balance dysfunction after spaceflight. For example, on return to Earth, an astronaut's vestibular input may be compromised by adaptation to microgravity, but their proprioceptive input is compromised by body unloading. Since proprioceptive and tactile input are important for maintaining postural control, keeping these systems tuned to respond to upright balance challenges during flight may improve functional task performance after flight through dynamic reweighting of sensory input. Novel approaches are needed to compensate for the challenges of balance training in microgravity and must be tested in a body unloading environment such as head down bed rest. Here, we review insights from the literature and provide observations from our laboratory that could inform the development of an in-flight proprioceptive countermeasure.
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Affiliation(s)
| | | | - Scott J. Wood
- NASA Johnson Space Center, Houston, TX, United States
| | | | - Lars Oddsson
- RxFunction Inc., Eden Prairie, MN, United States
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, United States
- Recaniti School for Community Health Professions, Ben Gurion University of the Negev, Beersheba, Israel
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10
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Hupfeld KE, McGregor HR, Reuter-Lorenz PA, Seidler RD. Microgravity effects on the human brain and behavior: Dysfunction and adaptive plasticity. Neurosci Biobehav Rev 2021; 122:176-189. [PMID: 33454290 DOI: 10.1016/j.neubiorev.2020.11.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 09/01/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
Emerging plans for travel to Mars and other deep space destinations make it critical for us to understand how spaceflight affects the human brain and behavior. Research over the past decade has demonstrated two co-occurring patterns of spaceflight effects on the brain and behavior: dysfunction and adaptive plasticity. Evidence indicates the spaceflight environment induces adverse effects on the brain, including intracranial fluid shifts, gray matter changes, and white matter declines. Past work also suggests that the spaceflight environment induces adaptive neural effects such as sensory reweighting and neural compensation. Here, we introduce a new conceptual framework to synthesize spaceflight effects on the brain, Spaceflight Perturbation Adaptation Coupled with Dysfunction (SPACeD). We review the literature implicating neurobehavioral dysfunction and adaptation in response to spaceflight and microgravity analogues, and we consider pre-, during-, and post-flight factors that may interact with these processes. We draw several instructive parallels with the aging literature which also suggests co-occurring neurobehavioral dysfunction and adaptive processes. We close with recommendations for future spaceflight research, including: 1) increased efforts to distinguish between dysfunctional versus adaptive effects by testing brain-behavioral correlations, and 2) greater focus on tracking recovery time courses.
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Affiliation(s)
- K E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - H R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - P A Reuter-Lorenz
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States
| | - R D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States; Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
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11
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Banker LA, Salazar AP, Lee JK, Beltran NE, Kofman IS, De Dios YE, Mulder E, Bloomberg JJ, Mulavara AP, Seidler RD. The effects of a spaceflight analog with elevated CO 2 on sensorimotor adaptation. J Neurophysiol 2020; 125:426-436. [PMID: 33296611 DOI: 10.1152/jn.00306.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Aboard the International Space Station (ISS), astronauts must adapt to altered vestibular and somatosensory inputs due to microgravity. Sensorimotor adaptation on Earth is often studied with a task that introduces visuomotor conflict. Retention of the adaptation process, known as savings, can be measured when subjects are exposed to the same adaptive task multiple times. It is unclear how adaptation demands found on the ISS might interfere with the ability to adapt to other sensory conflict at the same time. In the present study, we investigated the impact of 30 days' head-down tilt bed rest combined with elevated carbon dioxide (HDBR + CO2) as a spaceflight analog on sensorimotor adaptation. Eleven subjects used a joystick to move a cursor to targets presented on a computer screen under veridical cursor feedback and 45° rotated feedback. During this NASA campaign, five individuals presented with optic disk edema, a sign of spaceflight-associated neuro-ocular syndrome (SANS). Thus, we also performed post hoc exploratory analyses between subgroups who did and did not show signs of SANS. HDBR + CO2 had some impact on sensorimotor adaptation, with a lack of savings across the whole group. SANS individuals showed larger, more persistent after-effects, suggesting a shift from relying on cognitive to more implicit processing of adaptive behaviors. Overall, these findings suggest that HDBR + CO2 alters the way in which individuals engage in sensorimotor processing. These findings have important implications for missions and mission training, which require individuals to adapt to altered sensory inputs over long periods in space.NEW & NOTEWORTHY This is the first bed rest campaign examining sensorimotor adaptation and savings in response to the combined effect of HDBR + CO2 and to observe signs of spaceflight-associated neuro-ocular syndrome (SANS) in HDBR participants. Our findings suggest that HDBR + CO2 alters the way that individuals engage in sensorimotor processing. Individuals who developed signs of SANS seem to rely more on implicit rather than cognitive processing of adaptive behaviors than subjects who did not present signs of SANS.
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Affiliation(s)
- Lauren A Banker
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Ana Paula Salazar
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Jessica K Lee
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | | | | | | | - Edwin Mulder
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | | | | | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida.,Department of Neurology, University of Florida, Gainesville, Florida
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12
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McGregor HR, Lee JK, Mulder ER, De Dios YE, Beltran NE, Kofman IS, Bloomberg JJ, Mulavara AP, Seidler RD. Brain connectivity and behavioral changes in a spaceflight analog environment with elevated CO 2. Neuroimage 2020; 225:117450. [PMID: 33075558 DOI: 10.1016/j.neuroimage.2020.117450] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 09/18/2020] [Accepted: 10/08/2020] [Indexed: 12/22/2022] Open
Abstract
Astronauts are exposed to microgravity and elevated CO2 levels onboard the International Space Station. Little is known about how microgravity and elevated CO2 combine to affect the brain and sensorimotor performance during and after spaceflight. Here we examined changes in resting-state functional connectivity (FC) and sensorimotor behavior associated with a spaceflight analog environment. Participants underwent 30 days of strict 6o head-down tilt bed rest with elevated ambient CO2 (HDBR+CO2). Resting-state functional magnetic resonance imaging and sensorimotor assessments were collected 13 and 7 days prior to bed rest, on days 7 and 29 of bed rest, and 0, 5, 12, and 13 days following bed rest. We assessed the time course of FC changes from before, during, to after HDBR+CO2. We then compared the observed connectivity changes with those of a HDBR control group that underwent HDBR in standard ambient air. Moreover, we assessed associations between post-HDBR+CO2 FC changes and alterations in sensorimotor performance. HDBR+CO2 was associated with significant changes in functional connectivity between vestibular, visual, somatosensory and motor brain areas. Several of these sensory and motor regions showed post-HDBR+CO2 FC changes that were significantly associated with alterations in sensorimotor performance. We propose that these FC changes reflect multisensory reweighting associated with adaptation to the HDBR+CO2 microgravity analog environment. This knowledge will further improve HDBR as a model of microgravity exposure and contribute to our knowledge of brain and performance changes during and after spaceflight.
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Affiliation(s)
- Heather R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, 1864 Stadium Rd., Gainesville, FL 32611, United States
| | - Jessica K Lee
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Edwin R Mulder
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | | | | | | | | | | | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, 1864 Stadium Rd., Gainesville, FL 32611, United States.
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13
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Hupfeld KE, Lee JK, Gadd NE, Kofman IS, De Dios YE, Bloomberg JJ, Mulavara AP, Seidler RD. Neural Correlates of Vestibular Processing During a Spaceflight Analog With Elevated Carbon Dioxide (CO 2): A Pilot Study. Front Syst Neurosci 2020; 13:80. [PMID: 31998084 PMCID: PMC6965349 DOI: 10.3389/fnsys.2019.00080] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/09/2019] [Indexed: 11/13/2022] Open
Abstract
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.
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Affiliation(s)
- Kathleen E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Jessica K Lee
- German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany
| | | | | | | | | | | | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States.,Department of Neurology, University of Florida, Gainesville, FL, United States
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14
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The effect of bed rest on balance control in healthy adults: A systematic scoping review. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2020; 20:101-113. [PMID: 32131374 PMCID: PMC7104588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The objective of this study was to determine the effect of bed rest on balance control and the mechanisms responsible for these changes. Searches were conducted in six databases. Studies had to be conducted on healthy adults who were subjected to bed rest (≥5 days), with balance control measures obtained before and after bed rest in order to be included. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After screening 9,785 articles, 18 were included for qualitative synthesis. Fifteen studies found decrements in at least one balance control measure following bed rest, either compared to baseline or controls, with eight studies observing impairments in >50% of their balance control measures. Of the 14 studies that included an intervention, four (mechanical stimuli, lower-body negative pressure, and training targeting strength, balance and/or aerobic capacity) successfully offset the majority of balance control deficits and targeted the musculoskeletal and cardiovascular systems. The findings of this review support bed rest negatively affecting balance control in healthy individuals. In clinical populations, these deficits may be further accentuated due to various comorbidities that impact balance control systems. PROSPERO Registration: CRD42018098887.
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15
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Lee JK, De Dios Y, Kofman I, Mulavara AP, Bloomberg JJ, Seidler RD. Head Down Tilt Bed Rest Plus Elevated CO 2 as a Spaceflight Analog: Effects on Cognitive and Sensorimotor Performance. Front Hum Neurosci 2019; 13:355. [PMID: 31680909 PMCID: PMC6811492 DOI: 10.3389/fnhum.2019.00355] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 09/23/2019] [Indexed: 12/17/2022] Open
Abstract
Long duration head down tilt bed rest (HDBR) has been widely used as a spaceflight analog environment to understand the effects of microgravity on human physiology and performance. Reports have indicated that crewmembers onboard the International Space Station (ISS) experience symptoms of elevated CO2 such as headaches at lower levels of CO2 than levels at which symptoms begin to appear on Earth. This suggests there may be combinatorial effects of elevated CO2 and the other physiological effects of microgravity including headward fluid shifts and body unloading. The purpose of the current study was to investigate these effects by evaluating the impact of 30 days of 6° HDBR and 0.5% CO2 (HDBR + CO2) on mission relevant cognitive and sensorimotor performance. We found a facilitation of processing speed and a decrement in functional mobility for subjects undergoing HDBR + CO2 relative to our previous study of HDBR in ambient air. In addition, nearly half of the participants in this study developed signs of Spaceflight Associated Neuro-ocular Syndrome (SANS), a constellation of ocular structural and functional changes seen in approximately one third of long duration astronauts. This allowed us the unique opportunity to compare the two subgroups. We found that participants who exhibited signs of SANS became more visually dependent and shifted their speed-accuracy tradeoff, such that they were slower but more accurate than those that did not incur ocular changes. These small subgroup findings suggest that SANS may have an impact on mission relevant performance inflight via sensory reweighting.
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Affiliation(s)
- Jessica K Lee
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, United States.,German Aerospace Center, Cologne, Germany
| | | | | | | | | | - Rachael D Seidler
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, United States.,Department of Neurology, University of Florida, Gainesville, FL, United States
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16
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Ritzmann R, Freyler K, Kümmel J, Gruber M, Belavy DL, Felsenberg D, Gollhofer A, Kramer A, Ambrecht G. High Intensity Jump Exercise Preserves Posture Control, Gait, and Functional Mobility During 60 Days of Bed-Rest: An RCT Including 90 Days of Follow-Up. Front Physiol 2018; 9:1713. [PMID: 30559676 PMCID: PMC6287051 DOI: 10.3389/fphys.2018.01713] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/14/2018] [Indexed: 01/01/2023] Open
Abstract
Physical inactivity causes a deconditioning of the human body. Concerns due to chronic bed-rest include deficits in posture and gait control, predisposing individuals to an increased fall and injury risk. This study assessed the efficiency of a high-load jump exercise (JUMP) as a countermeasure to prevent detrimental effects on gait, posture control and functional mobility. In an RCT (23 males), the effect of 60 days bed-rest without training was compared to JUMP. JUMP is characterized by plyometric executed as a high intensity interval training. Typical trainings session consisted of 4 × 10 countermovement jumps and 2 × 10 hops in a sledge jump system. We assessed sway path and muscle activity in monopedal stance, spatiotemporal, kinematic, and variability characteristics in gait, functional mobility with repeated chair-rises and Timed Up and Go (TUG). Results revealed: The JUMP group showed no significant changes after bed-rest, whereas the control group exhibited substantial deteriorations: an increased sway path (+104%, p < 0.05) was accompanied by increased co-contractions of antagonistic muscles encompassing the ankle (+32%, p < 0.05) and knee joint (45%, p < 0.05). A reduced locomotor speed (−22%, p < 0.05) was found concomitant with pathological gait rhythmicity (p < 0.05), reduced joint excursions (ankle −8%, knee −29%, p < 0.05) and an increased gait variability (p < 0.05). Chair-rising was slowed (+28%, p < 0.05) with reduced peak power (+18%, p < 0.05), and more time was needed to accomplish TUG (+39%, p < 0.05). The effects persisted for a period of 1 month after bed-rest. Increases in sway path were correlated to decreases in gait speed. The JUMP effectively preserved the neuromuscular system's ability to safely control postural equilibrium and perform complex locomotor movements, including fast bipedal gait with turns and rises. We therefore recommend JUMP as an appropriate strategy combatting functional deconditioning.
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Affiliation(s)
- Ramona Ritzmann
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Kathrin Freyler
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Jakob Kümmel
- Sensorimotor Performance Lab and Human Performance Research Centre, University of Konstanz, Konstanz, Germany
| | - Markus Gruber
- Sensorimotor Performance Lab and Human Performance Research Centre, University of Konstanz, Konstanz, Germany
| | - Daniel L Belavy
- Centre of Muscle and Bone Research, Charité University Medicine Berlin, Berlin, Germany.,Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Dieter Felsenberg
- Centre of Muscle and Bone Research, Charité University Medicine Berlin, Berlin, Germany
| | - Albert Gollhofer
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Andreas Kramer
- Sensorimotor Performance Lab and Human Performance Research Centre, University of Konstanz, Konstanz, Germany
| | - Gabriele Ambrecht
- Centre of Muscle and Bone Research, Charité University Medicine Berlin, Berlin, Germany
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17
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Koppelmans V, Scott JM, Downs ME, Cassady KE, Yuan P, Pasternak O, Wood SJ, De Dios YE, Gadd NE, Kofman I, Riascos R, Reuter-Lorenz PA, Bloomberg JJ, Mulavara AP, Ploutz-Snyder LL, Seidler RD. Exercise effects on bed rest-induced brain changes. PLoS One 2018; 13:e0205515. [PMID: 30308004 PMCID: PMC6181401 DOI: 10.1371/journal.pone.0205515] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 09/26/2018] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Spaceflight negatively affects sensorimotor behavior; exercise mitigates some of these effects. Head down tilt bed rest (HDBR) induces body unloading and fluid shifts, and is often used to investigate spaceflight effects. Here, we examined whether exercise mitigates effects of 70 days HDBR on the brain and if fitness and brain changes with HDBR are related. METHODS HDBR subjects were randomized to no-exercise (n = 5) or traditional aerobic and resistance exercise (n = 5). Additionally, a flywheel exercise group was included (n = 8). Exercise protocols for exercise groups were similar in intensity, therefore these groups were pooled in statistical analyses. Pre and post-HDBR MRI (structure and structural/functional connectivity) and physical fitness measures (lower body strength, muscle cross sectional area, VO2 max, body composition) were collected. Voxel-wise permutation analyses were used to test group differences in brain changes, and their associations with fitness changes. RESULTS Comparisons of exercisers to controls revealed that exercise led to smaller fitness deterioration with HDBR but did not affect brain volume or connectivity. Group comparisons showed that exercise modulated post-HDBR recovery of brain connectivity in somatosensory regions. Posthoc analysis showed that this was related to functional connectivity decrease with HDBR in non-exercisers but not in exercisers. Correlational analyses between fitness and brain changes showed that fitness decreases were associated with functional connectivity and volumetric increases (all r >.74), potentially reflecting compensation. Modest brain changes or even decreases in connectivity and volume were observed in subjects who maintained or showed small fitness gains. These results did not survive Bonferroni correction, but can be considered meaningful because of the large effect sizes. CONCLUSION Exercise performed during HDBR mitigates declines in fitness and strength. Associations between fitness and brain connectivity and volume changes, although unadjusted for multiple comparisons in this small sample, suggest that supine exercise reduces compensatory HDBR-induced brain changes.
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Affiliation(s)
- Vincent Koppelmans
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Psychiatry, University of Utah, Salt Lake City, Utah, United States of America
| | - Jessica M. Scott
- Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
- Universities Space Research Association, NASA Johnson Space Center, Houston, Texas, United States of America
| | | | - Kaitlin E. Cassady
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peng Yuan
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ofer Pasternak
- Department of Psychiatry and Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Scott J. Wood
- NASA Johnson Space Center, Houston, Texas, United States of America
| | | | | | - Igor Kofman
- KBRwyle, Houston, Texas, United States of America
| | - Roy Riascos
- The University of Texas Health Science Center, Houston, Texas, United States of America
| | - Patricia A. Reuter-Lorenz
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neuroscience Program, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | | | - Lori L. Ploutz-Snyder
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Universities Space Research Association, NASA Johnson Space Center, Houston, Texas, United States of America
| | - Rachael D. Seidler
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, Florida, United States of America
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18
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Yuan P, Koppelmans V, Reuter-Lorenz P, De Dios Y, Gadd N, Wood S, Riascos R, Kofman I, Bloomberg J, Mulavara A, Seidler R. Vestibular brain changes within 70 days of head down bed rest. Hum Brain Mapp 2018. [PMID: 29528169 DOI: 10.1002/hbm.24037] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Head-down-tilt bed rest (HDBR) is frequently utilized as a spaceflight analog research environment to study the effects of axial body unloading and fluid shifts that are associated with spaceflight in the absence of gravitational modifications. HDBR has been shown to result in balance changes, presumably due to sensory reweighting and adaptation processes. Here, we examined whether HDBR results in changes in the neural correlates of vestibular processing. Thirteen men participated in a 70-day HDBR intervention; we measured balance, functional mobility, and functional brain activity in response to vestibular stimulation at 7 time points before, during, and after HDBR. Vestibular stimulation was administered by means of skull taps, resulting in activation of the vestibular cortex and deactivation of the cerebellar, motor, and somatosensory cortices. Activation in the bilateral insular cortex, part of the vestibular network, gradually increased across the course of HDBR, suggesting an upregulation of vestibular inputs in response to the reduced somatosensory inputs experienced during bed rest. Furthermore, greater increase of activation in multiple frontal, parietal, and occipital regions in response to vestibular stimulation during HDBR was associated with greater decrements in balance and mobility from before to after HDBR, suggesting reduced neural efficiency. These findings shed light on neuroplastic changes occurring with conditions of altered sensory inputs, and reveal the potential for central vestibular-somatosensory convergence and reweighting with bed rest.
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Affiliation(s)
- Peng Yuan
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan
| | | | | | - Yiri De Dios
- Wyle Science, Technology & Engineering Group, Houston, Texas
| | - Nichole Gadd
- Wyle Science, Technology & Engineering Group, Houston, Texas
| | - Scott Wood
- Department of Psychology, Azusa Pacific University, Azusa, California
| | - Roy Riascos
- The University of Texas Health Science Center, Houston, Texas
| | - Igor Kofman
- Wyle Science, Technology & Engineering Group, Houston, Texas
| | | | - Ajitkumar Mulavara
- NASA Johnson Space Center, Houston, Texas.,Universities Space Research Association, Houston, Texas
| | - Rachael Seidler
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,Department of Applied Physiology & Kinesiology, University of Florida, Gainesville, Florida
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19
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Yuan P, Koppelmans V, Reuter-Lorenz P, De Dios Y, Gadd N, Riascos R, Kofman I, Bloomberg J, Mulavara A, Seidler RD. Change of cortical foot activation following 70 days of head-down bed rest. J Neurophysiol 2018; 119:2145-2152. [PMID: 29488843 DOI: 10.1152/jn.00693.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Head-down tilt bed rest (HDBR) has been used as a spaceflight analog to study some of the effects of microgravity on human physiology, cognition, and sensorimotor functions. Previous studies have reported declines in balance control and functional mobility after spaceflight and HDBR. In this study we investigated how the brain activation for foot movement changed with HDBR. Eighteen healthy men participated in the current HDBR study. They were in a 6° head-down tilt position continuously for 70 days. Functional MRI scans were acquired to estimate brain activation for foot movement before, during, and after HDBR. Another 11 healthy men who did not undergo HDBR participated as control subjects and were scanned at four time points. In the HDBR subjects, the cerebellum, fusiform gyrus, hippocampus, and middle occipital gyrus exhibited HDBR-related increases in activation for foot tapping, whereas no HDBR-associated activation decreases were found. For the control subjects, activation for foot tapping decreased across sessions in a couple of cerebellar regions, whereas no activation increase with session was found. Furthermore, we observed that less HDBR-related decline in functional mobility and balance control was associated with greater pre-to-post HDBR increases in brain activation for foot movement in several cerebral and cerebellar regions. Our results suggest that more neural control is needed for foot movement as a result of HDBR. NEW & NOTEWORTHY Long-duration head-down bed rest serves as a spaceflight analog research environment. We show that brain activity in the cerebellum and visual areas during foot movement increases from pre- to post-bed rest and then shows subsequent recovery. Greater increases were seen for individuals who exhibited less decline in functional mobility and balance control, suggestive of adaptive changes in neural control with long-duration bed rest.
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Affiliation(s)
- Peng Yuan
- School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Vincent Koppelmans
- School of Kinesiology, University of Michigan , Ann Arbor, Michigan.,Department of Psychiatry, University of Utah , Salt Lake City, Utah
| | | | | | | | - Roy Riascos
- The University of Texas Health Science Center , Houston, Texas
| | | | | | | | - Rachael D Seidler
- School of Kinesiology, University of Michigan , Ann Arbor, Michigan.,Department of Applied Physiology & Kinesiology, University of Florida , Gainesville, Florida
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20
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Booth FW, Roberts CK, Thyfault JP, Ruegsegger GN, Toedebusch RG. Role of Inactivity in Chronic Diseases: Evolutionary Insight and Pathophysiological Mechanisms. Physiol Rev 2017; 97:1351-1402. [PMID: 28814614 PMCID: PMC6347102 DOI: 10.1152/physrev.00019.2016] [Citation(s) in RCA: 329] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 12/13/2022] Open
Abstract
This review proposes that physical inactivity could be considered a behavior selected by evolution for resting, and also selected to be reinforcing in life-threatening situations in which exercise would be dangerous. Underlying the notion are human twin studies and animal selective breeding studies, both of which provide indirect evidence for the existence of genes for physical inactivity. Approximately 86% of the 325 million in the United States (U.S.) population achieve less than the U.S. Government and World Health Organization guidelines for daily physical activity for health. Although underappreciated, physical inactivity is an actual contributing cause to at least 35 unhealthy conditions, including the majority of the 10 leading causes of death in the U.S. First, we introduce nine physical inactivity-related themes. Next, characteristics and models of physical inactivity are presented. Following next are individual examples of phenotypes, organ systems, and diseases that are impacted by physical inactivity, including behavior, central nervous system, cardiorespiratory fitness, metabolism, adipose tissue, skeletal muscle, bone, immunity, digestion, and cancer. Importantly, physical inactivity, itself, often plays an independent role as a direct cause of speeding the losses of cardiovascular and strength fitness, shortening of healthspan, and lowering of the age for the onset of the first chronic disease, which in turn decreases quality of life, increases health care costs, and accelerates mortality risk.
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Affiliation(s)
- Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles Healthcare System, Los Angeles, California; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; and Cardiovascular Division, Department of Medicine, University of Missouri, Columbia, Missouri
| | - Christian K Roberts
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles Healthcare System, Los Angeles, California; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; and Cardiovascular Division, Department of Medicine, University of Missouri, Columbia, Missouri
| | - John P Thyfault
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles Healthcare System, Los Angeles, California; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; and Cardiovascular Division, Department of Medicine, University of Missouri, Columbia, Missouri
| | - Gregory N Ruegsegger
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles Healthcare System, Los Angeles, California; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; and Cardiovascular Division, Department of Medicine, University of Missouri, Columbia, Missouri
| | - Ryan G Toedebusch
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles Healthcare System, Los Angeles, California; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas; and Cardiovascular Division, Department of Medicine, University of Missouri, Columbia, Missouri
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21
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Reschke MF, Good EF, Clément GR. Neurovestibular Symptoms in Astronauts Immediately after Space Shuttle and International Space Station Missions. OTO Open 2017; 1:2473974X17738767. [PMID: 30480196 PMCID: PMC6239149 DOI: 10.1177/2473974x17738767] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/22/2017] [Accepted: 10/04/2017] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES (1) To assess vestibular changes and related sensorimotor difficulties, especially instability of posture and gait, among astronauts immediately after they return from space and to compare the effects experienced after short- and long-duration space missions. (2) To determine whether any difficulties experienced were severe enough to impair the astronauts' ability to leave the spacecraft in the event of an emergency. STUDY DESIGN Prospective cohort study. SETTING National Aeronautics and Space Administration's Kennedy Space Center and Johnson Space Center. SUBJECTS AND METHODS Fourteen crewmembers of 3 Space Shuttle missions that lasted about 1 week and 18 crewmembers of 8 International Space Station missions that lasted about 6 months were given brief vestibular examinations 1 to 5 hours after landing. These examinations focused on the presence of vestibular and motor coordination difficulties, as well as motion sickness and motion sensations. Standardized tests included the observation of abnormal eye movements, finger-to-nose pointing, standing up from a seated position, postural stability, and tandem gait. RESULTS Unsteady walking and postural instabilities were observed after short- and long-duration missions. Motion sickness symptoms were observed after long-duration missions but not after short-duration missions. The symptom most frequently reported by the astronauts was an exaggerated perceived motion associated with sudden head movements during reentry and after landing. CONCLUSION The severity of the observed abnormalities would limit the ability of crewmembers during the first 5 hours after landing and increase the time required to leave the spacecraft during this period.
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Affiliation(s)
- Millard F. Reschke
- Neuroscience Laboratories, Johnson Space
Center, National Aeronautics and Space Administration, Houston, Texas, USA
| | - Edward F. Good
- Baylor College of Medicine, University
of Texas Health Science Center, Houston, Texas, USA
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22
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Ruitenberg MFL, De Dios YE, Gadd NE, Wood SJ, Reuter-Lorenz PA, Kofman I, Bloomberg JJ, Mulavara AP, Seidler RD. Multi-day Adaptation and Savings in Manual and Locomotor Tasks. J Mot Behav 2017; 50:517-527. [PMID: 28937868 DOI: 10.1080/00222895.2017.1371110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using an individual differences approach, we evaluated whether manual and locomotor adaptation are associated in terms of adaptation and savings across days, and whether they rely on shared underlying mechanisms involving visuospatial working memory or visual field dependence. Participants performed a manual and a locomotor adaptation task during 4 separate test sessions over a 3-month period. Reliable adaptation and savings were observed for both tasks. It was further found that higher visuospatial working memory performance and lower visual field dependence scores were associated with faster learning in the manual and locomotor tasks, respectively. Moreover, adaptation rates were correlated between the 2 tasks in the final test session, suggesting that people may gradually be learning something generalizable about the adaptation process.
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Affiliation(s)
- M F L Ruitenberg
- a Neuromotor Behavior Lab, School of Kinesiology , University of Michigan , Ann Arbor.,b Department of Experimental Psychology , Ghent University , Belgium
| | - Y E De Dios
- c Science, Technology, and Engineering Group, KBRwyle Houston , Texas
| | - N E Gadd
- c Science, Technology, and Engineering Group, KBRwyle Houston , Texas
| | - S J Wood
- d NASA Johnson Space Center , Houston , Texas
| | | | - I Kofman
- b Department of Experimental Psychology , Ghent University , Belgium
| | | | | | - R D Seidler
- a Neuromotor Behavior Lab, School of Kinesiology , University of Michigan , Ann Arbor.,e Department of Psychology , University of Michigan , Ann Arbor
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23
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Koppelmans V, Bloomberg JJ, De Dios YE, Wood SJ, Reuter-Lorenz PA, Kofman IS, Riascos R, Mulavara AP, Seidler RD. Brain plasticity and sensorimotor deterioration as a function of 70 days head down tilt bed rest. PLoS One 2017; 12:e0182236. [PMID: 28767698 PMCID: PMC5540603 DOI: 10.1371/journal.pone.0182236] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 07/15/2017] [Indexed: 12/18/2022] Open
Abstract
Background Adverse effects of spaceflight on sensorimotor function have been linked to altered somatosensory and vestibular inputs in the microgravity environment. Whether these spaceflight sequelae have a central nervous system component is unknown. However, experimental studies have shown spaceflight-induced brain structural changes in rodents’ sensorimotor brain regions. Understanding the neural correlates of spaceflight-related motor performance changes is important to ultimately develop tailored countermeasures that ensure mission success and astronauts’ health. Method Head down-tilt bed rest (HDBR) can serve as a microgravity analog because it mimics body unloading and headward fluid shifts of microgravity. We conducted a 70-day 6° HDBR study with 18 right-handed males to investigate how microgravity affects focal gray matter (GM) brain volume. MRI data were collected at 7 time points before, during and post-HDBR. Standing balance and functional mobility were measured pre and post-HDBR. The same metrics were obtained at 4 time points over ~90 days from 12 control subjects, serving as reference data. Results HDBR resulted in widespread increases GM in posterior parietal regions and decreases in frontal areas; recovery was not yet complete by 12 days post-HDBR. Additionally, HDBR led to balance and locomotor performance declines. Increases in a cluster comprising the precuneus, precentral and postcentral gyrus GM correlated with less deterioration or even improvement in standing balance. This association did not survive Bonferroni correction and should therefore be interpreted with caution. No brain or behavior changes were observed in control subjects. Conclusions Our results parallel the sensorimotor deficits that astronauts experience post-flight. The widespread GM changes could reflect fluid redistribution. Additionally, the association between focal GM increase and balance changes suggests that HDBR also may result in neuroplastic adaptation. Future studies are warranted to determine causality and underlying mechanisms.
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Affiliation(s)
- Vincent Koppelmans
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | | | - Scott J. Wood
- NASA Johnson Space Center, Houston, TX, United States of America
| | | | | | - Roy Riascos
- The University of Texas Health Science Center, Houston, TX, United States of America
| | | | - Rachael D. Seidler
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neuroscience Program, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Koppelmans V, Pasternak O, Bloomberg JJ, Dios YED, Wood SJ, Riascos R, Reuter-Lorenz PA, Kofman IS, Mulavara AP, Seidler RD. Intracranial Fluid Redistribution But No White Matter Microstructural Changes During a Spaceflight Analog. Sci Rep 2017; 7:3154. [PMID: 28600534 PMCID: PMC5466616 DOI: 10.1038/s41598-017-03311-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/25/2017] [Indexed: 01/01/2023] Open
Abstract
The neural correlates of spaceflight-induced sensorimotor impairments are unknown. Head down-tilt bed rest (HDBR) serves as a microgravity analog because it mimics the headward fluid shift and axial body unloading of spaceflight. We investigated focal brain white matter (WM) changes and fluid shifts during 70 days of 6° HDBR in 16 subjects who were assessed pre (2x), during (3x), and post-HDBR (2x). Changes over time were compared to those in control subjects (n = 12) assessed four times over 90 days. Diffusion MRI was used to assess WM microstructure and fluid shifts. Free-Water Imaging was used to quantify distribution of intracranial extracellular free water (FW). Additionally, we tested whether WM and FW changes correlated with changes in functional mobility and balance measures. HDBR resulted in FW increases in fronto-temporal regions and decreases in posterior-parietal regions that largely recovered by two weeks post-HDBR. WM microstructure was unaffected by HDBR. FW decreases in the post-central gyrus and precuneus correlated negatively with balance changes. We previously reported that gray matter increases in these regions were associated with less HDBR-induced balance impairment, suggesting adaptive structural neuroplasticity. Future studies are warranted to determine causality and underlying mechanisms.
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Affiliation(s)
- Vincent Koppelmans
- School of Kinesiology, University of Michigan, Ann Arbor, MI, United States
| | - Ofer Pasternak
- Departments of Psychiatry and Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | | | | | - Scott J Wood
- NASA Johnson Space Center, Houston, TX, United States
- Azusa Pacific University, Azusa, CA, United States
| | - Roy Riascos
- The University of Texas Health Science Center, Houston, TX, United States
| | | | | | | | - Rachael D Seidler
- School of Kinesiology, University of Michigan, Ann Arbor, MI, United States.
- Department of Psychology, University of Michigan, Ann Arbor, MI, United States.
- Neuroscience Program, University of Michigan, Ann Arbor, MI, United States.
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Koppelmans V, Bloomberg JJ, Mulavara AP, Seidler RD. Brain structural plasticity with spaceflight. NPJ Microgravity 2016; 2:2. [PMID: 28649622 PMCID: PMC5460234 DOI: 10.1038/s41526-016-0001-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 09/08/2016] [Accepted: 10/27/2016] [Indexed: 11/30/2022] Open
Abstract
Humans undergo extensive sensorimotor adaptation during spaceflight due to altered vestibular inputs and body unloading. No studies have yet evaluated the effects of spaceflight on human brain structure despite the fact that recently reported optic nerve structural changes are hypothesized to occur due to increased intracranial pressure occurring with microgravity. This is the first report on human brain structural changes with spaceflight. We evaluated retrospective longitudinal T2-weighted MRI scans and balance data from 27 astronauts (thirteen ~2-week shuttle crew members and fourteen ~6-month International Space Station crew members) to determine spaceflight effects on brain structure, and whether any pre to postflight brain changes are associated with balance changes. Data were obtained from the NASA Lifetime Surveillance of Astronaut Health. Brain scans were segmented into gray matter maps and normalized into MNI space using a stepwise approach through subject specific templates. Non-parametric permutation testing was used to analyze pre to postflight volumetric gray matter changes. We found extensive volumetric gray matter decreases, including large areas covering the temporal and frontal poles and around the orbits. This effect was larger in International Space Station versus shuttle crew members in some regions. There were bilateral focal gray matter increases within the medial primary somatosensory and motor cortex; i.e., the cerebral areas where the lower limbs are represented. These intriguing findings are observed in a retrospective data set; future prospective studies should probe the underlying mechanisms and behavioral consequences.
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Affiliation(s)
- Vincent Koppelmans
- School of Kinesiology, University of Michigan, 401 Washtenaw Ave., Ann Arbor, MI 48109-2214 USA
| | | | | | - Rachael D Seidler
- School of Kinesiology, University of Michigan, 401 Washtenaw Ave., Ann Arbor, MI 48109-2214 USA
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109 USA
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Marusic U, Giordani B, Moffat SD, Petrič M, Dolenc P, Pišot R, Kavcic V. Computerized cognitive training during physical inactivity improves executive functioning in older adults. AGING NEUROPSYCHOLOGY AND COGNITION 2016; 25:49-69. [PMID: 27937138 DOI: 10.1080/13825585.2016.1263724] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The hippocampus is closely tied to spatial navigation, a central component in cognitive functioning, and critically involved in age-associated cognitive decline and dementia. This study evaluated a novel, cognitive computerized spatial navigation training (CSNT) program targeting the hippocampus, with expectation of mitigating possible cognitive decline with bed rest (BR). During a 14-day BR study with 16 healthy, older men (mean age = 60 ± 3, range = 55-65 years), half received CSNT for 12 days in 50-min sessions and half were controls (watching documentaries). This design uniquely controlled diet, sleep, and other personal and environmental activities. Although there were no cognitive declines in controls post-BR, CSNT participants demonstrated significant increases in executive/attention ability and processing speed, and continued spatial navigation testing showed improvement to 400 days post-BR. This intervention may prove useful to mitigate cognitive declines known to occur in long periods of immobilization and could have broader implications in protecting against age-related cognitive decline.
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Affiliation(s)
- Uros Marusic
- a Institute for Kinesiology Research, Science and Research Centre , University of Primorska , Koper , Slovenia
| | - Bruno Giordani
- b Departments of Psychiatry, Neurology, and Psychology and School of Nursing , University of Michigan , Ann Arbor , MI , USA
| | - Scott D Moffat
- c School of Psychology , Georgia Institute of Technology , Atlanta , GA , USA
| | - Mojca Petrič
- d Faculty of Education , University of Primorska , Koper , Slovenia
| | - Petra Dolenc
- d Faculty of Education , University of Primorska , Koper , Slovenia
| | - Rado Pišot
- a Institute for Kinesiology Research, Science and Research Centre , University of Primorska , Koper , Slovenia
| | - Voyko Kavcic
- e Institute of Gerontology , Wayne State University , Detroit , MI , USA
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Cassady K, Koppelmans V, Reuter-Lorenz P, De Dios Y, Gadd N, Wood S, Castenada RR, Kofman I, Bloomberg J, Mulavara A, Seidler R. Effects of a spaceflight analog environment on brain connectivity and behavior. Neuroimage 2016; 141:18-30. [DOI: 10.1016/j.neuroimage.2016.07.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/22/2016] [Accepted: 07/12/2016] [Indexed: 01/25/2023] Open
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Yuan P, Koppelmans V, Reuter-Lorenz PA, De Dios YE, Gadd NE, Wood SJ, Riascos R, Kofman IS, Bloomberg JJ, Mulavara AP, Seidler RD. Increased Brain Activation for Dual Tasking with 70-Days Head-Down Bed Rest. Front Syst Neurosci 2016; 10:71. [PMID: 27601982 PMCID: PMC4993791 DOI: 10.3389/fnsys.2016.00071] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/05/2016] [Indexed: 01/24/2023] Open
Abstract
Head-down tilt bed rest (HDBR) has been used as a spaceflight analog to simulate the effects of microgravity exposure on human physiology, sensorimotor function, and cognition on Earth. Previous studies have reported that concurrent performance of motor and cognitive tasks can be impaired during space missions. Understanding the consequences of HDBR for neural control of dual tasking may possibly provide insight into neural efficiency during spaceflight. In the current study, we evaluated how dual task performance and the underlying brain activation changed as a function of HDBR. Eighteen healthy men participated in this study. They remained continuously in the 6° head-down tilt position for 70 days. Functional MRI for bimanual finger tapping was acquired during both single task and dual task conditions, and repeated at 7 time points pre-, during- and post-HDBR. Another 12 healthy males participated as controls who did not undergo HDBR. A widely distributed network involving the frontal, parietal, cingulate, temporal, and occipital cortices exhibited increased activation for dual tasking and increased activation differences between dual and single task conditions during HDBR relative to pre- or post-HDBR. This HDBR-related brain activation increase for dual tasking implies that more neurocognitive control is needed for dual task execution during HDBR compared to pre- and post-HDBR. We observed a positive correlation between pre-to-post HDBR changes in dual-task cost of reaction time and pre-to-post HDBR change in dual-task cost of brain activation in several cerebral and cerebellar regions. These findings could be predictive of changes in dual task processing during spaceflight.
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Affiliation(s)
- Peng Yuan
- School of Kinesiology, University of Michigan Ann Arbor, MI, USA
| | | | | | - Yiri E De Dios
- Wyle Science, Technology and Engineering Group Houston, TX, USA
| | - Nichole E Gadd
- Wyle Science, Technology and Engineering Group Houston, TX, USA
| | - Scott J Wood
- Department of Psychology, Azusa Pacific University Azusa, CA, USA
| | - Roy Riascos
- The University of Texas Health Science Center Houston, TX, USA
| | - Igor S Kofman
- Wyle Science, Technology and Engineering Group Houston, TX, USA
| | | | - Ajitkumar P Mulavara
- NASA Johnson Space CenterHouston, TX, USA; Universities Space Research AssociationHouston, TX, USA
| | - Rachael D Seidler
- School of Kinesiology, University of MichiganAnn Arbor, MI, USA; Department of Psychology, University of MichiganAnn Arbor, MI, USA; Neuroscience Program, Medical School, University of MichiganAnn Arbor, MI, USA
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Macaulay TR, Macias BR, Lee SM, Boda WL, Watenpaugh DE, Hargens AR. Treadmill exercise within lower-body negative pressure attenuates simulated spaceflight-induced reductions of balance abilities in men but not women. NPJ Microgravity 2016; 2:16022. [PMID: 28725733 PMCID: PMC5515523 DOI: 10.1038/npjmgrav.2016.22] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 11/09/2022] Open
Abstract
Spaceflight causes sensorimotor adaptations that result in balance deficiencies on return to a gravitational environment. Treadmill exercise within lower-body negative pressure (LBNP) helps protect physiological function during microgravity as simulated by bed rest. Therefore, we hypothesized that treadmill exercise within LBNP would prevent balance losses in both male and female identical twins during 30 days of 6° head-down tilt bed rest. Fifteen (seven female and eight male) identical twin sets participated in this simulation of microgravity. Within each twin pair, one twin was randomly assigned to an exercise group that performed 40 min of supine treadmill exercise within LBNP set to generate 1.0–1.2 body weight, followed by 5 min of static feet-supported LBNP, 6 days per week. Their identical sibling was assigned to a non-exercise control group with all other bed rest conditions equivalent. Before and immediately after bed rest, subjects completed standing and walking rail balance tests with eyes open and eyes closed. In control subjects, standing rail balance times (men: −42%, women: −40%), rail walk distances (men: −44%, women: −32%) and rail walk times (men: −34%, women: −31%) significantly decreased after bed rest. Compared with controls, treadmill exercise within LBNP significantly attenuated losses of standing rail balance time by 63% in men, but the 41% attenuation in women was not significant. Treadmill exercise within LBNP did not affect rail walk abilities in men or women. Treadmill exercise within LBNP during simulated spaceflight attenuates loss of balance control in men but not in women.
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Affiliation(s)
- Timothy R Macaulay
- Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, USA
| | - Brandon R Macias
- Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, USA
| | - Stuart Mc Lee
- Cardiovascular Laboratory, Wyle Science, Technology and Engineering Group, Houston, TX, USA
| | - Wanda L Boda
- Department of Kinesiology, Sonoma State University, Rohnert Park, CA, USA
| | - Donald E Watenpaugh
- Department of Integrated Physiology, University of North Texas, Fort Worth, TX, USA
| | - Alan R Hargens
- Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, USA
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Watenpaugh DE. Analogs of microgravity: head-down tilt and water immersion. J Appl Physiol (1985) 2016; 120:904-14. [DOI: 10.1152/japplphysiol.00986.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/04/2016] [Indexed: 01/26/2023] Open
Abstract
This article briefly reviews the fidelity of ground-based methods used to simulate human existence in weightlessness (spaceflight). These methods include horizontal bed rest (BR), head-down tilt bed rest (HDT), head-out water immersion (WI), and head-out dry immersion (DI; immersion with an impermeable elastic cloth barrier between subject and water). Among these, HDT has become by far the most commonly used method, especially for longer studies. DI is less common but well accepted for long-duration studies. Very few studies exist that attempt to validate a specific simulation mode against actual microgravity. Many fundamental physical, and thus physiological, differences exist between microgravity and our methods to simulate it, and between the different methods. Also, although weightlessness is the salient feature of spaceflight, several ancillary factors of space travel complicate Earth-based simulation. In spite of these discrepancies and complications, the analogs duplicate many responses to 0 G reasonably well. As we learn more about responses to microgravity and spaceflight, investigators will continue to fine-tune simulation methods to optimize accuracy and applicability.
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Affiliation(s)
- Donald E. Watenpaugh
- Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas
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