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Mackenzie SW, Smith CP, Tremblay MF, Day BL, Reynolds RF. Bed rest impairs the vestibular control of balance. J Physiol 2024. [PMID: 38766932 DOI: 10.1113/jp285834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 04/18/2024] [Indexed: 05/22/2024] Open
Abstract
Prolonged bed rest impairs standing balance but the underlying mechanisms are uncertain. Previous research suggests strength loss is not the cause, leaving impaired sensorimotor control as an alternative. Here we examine vestibular control of posture in 18 male volunteers before and after 60 days of bed rest. Stochastic vestibular stimulation (SVS) was used to evoke sway responses before, 1 and 6 days after bed rest under different head yaw orientations. The directional accuracy and precision of these responses were calculated from ground reaction force vectors. Bed rest caused up to 63% increases in spontaneous standing sway and 31% reductions in leg strength, changes which were uncorrelated. The increase in sway was exacerbated when the eyes were closed. Mean directions of SVS-evoked sway responses were unaffected, being directed towards the anodal ear and rotating in line with head orientation in the same way before and after bed rest. However, individual trial analysis revealed 25%-30% increases in directional variability, which were significantly correlated with the increase in spontaneous sway (r = 0.48-0.71; P ≤ 0.044) and were still elevated on day 6 post-bed rest. This reveals that individual sway responses may be inappropriately oriented, a finding masked by the averaging process. Our results confirm that impaired balance following prolonged bedrest is not related to loss of strength. Rather, they demonstrate that the sensorimotor transformation process which converts vestibular feedback into appropriately directed balance responses is impaired. KEY POINTS: Prolonged inactivity impairs balance but previous research suggests this is not caused by loss of strength. Here we investigated vestibular control of balance before and after 60 days of bed rest using electrical vestibular stimulation (EVS) to evoke sway responses. Spontaneous sway significantly increased and muscle strength reduced following bed rest, but, in keeping with previous research, these two effects were not correlated. While the overall accuracy of EVS-evoked sway responses was unaffected, their directional variability significantly increased following bed rest, and this was correlated with the increases in spontaneous sway. We have shown that the ability to transform head-centred vestibular feedback into an appropriately directed body sway response is negatively affected by prolonged inactivity; this may contribute to the impaired balance commonly observed following bed rest.
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Affiliation(s)
- Stuart W Mackenzie
- School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Craig P Smith
- School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Malcom F Tremblay
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Brian L Day
- Department of Clinical and Movement Neurosciences, University College London, London, UK
| | - Raymond F Reynolds
- School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
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2
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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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3
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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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4
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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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5
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Salazar AP, McGregor HR, Hupfeld KE, Beltran NE, Kofman IS, De Dios YE, Riascos RF, Reuter-Lorenz PA, Bloomberg JJ, Mulavara AP, Wood SJ, Seidler R. Changes in working memory brain activity and task-based connectivity after long-duration spaceflight. Cereb Cortex 2023; 33:2641-2654. [PMID: 35704860 PMCID: PMC10016051 DOI: 10.1093/cercor/bhac232] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
We studied the longitudinal effects of approximately 6 months of spaceflight on brain activity and task-based connectivity during a spatial working memory (SWM) task. We further investigated whether any brain changes correlated with changes in SWM performance from pre- to post-flight. Brain activity was measured using functional magnetic resonance imaging while astronauts (n = 15) performed a SWM task. Data were collected twice pre-flight and 4 times post-flight. No significant effects on SWM performance or brain activity were found due to spaceflight; however, significant pre- to post-flight changes in brain connectivity were evident. Superior occipital gyrus showed pre- to post-flight reductions in task-based connectivity with the rest of the brain. There was also decreased connectivity between the left middle occipital gyrus and the left parahippocampal gyrus, left cerebellum, and left lateral occipital cortex during SWM performance. These results may reflect increased visual network modularity with spaceflight. Further, increased visual and visuomotor connectivity were correlated with improved SWM performance from pre- to post-flight, while decreased visual and visual-frontal cortical connectivity were associated with poorer performance post-flight. These results suggest that while SWM performance remains consistent from pre- to post-flight, underlying changes in connectivity among supporting networks suggest both disruptive and compensatory alterations due to spaceflight.
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Affiliation(s)
| | - Heather R McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Kathleen E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | | | - Igor S Kofman
- KBR, 601 Jefferson Street, Houston, TX 77002, United States
| | - Yiri E De Dios
- KBR, 601 Jefferson Street, Houston, TX 77002, United States
| | - Roy F Riascos
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States
| | - Patricia A Reuter-Lorenz
- Department of Psychology, University of Michigan, 530 Church St., Ann Arbor, MI 48109, United States
| | - Jacob J Bloomberg
- NASA Johnson Space Center, 2101 E NASA Parkway, Houston, TX 77058, United States
| | | | - Scott J Wood
- NASA Johnson Space Center, 2101 E NASA Parkway, Houston, TX 77058, United States
| | - RachaelD Seidler
- Corresponding author: Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
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6
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Saveko A, Bekreneva M, Ponomarev I, Zelenskaya I, Riabova A, Shigueva T, Kitov V, Abu Sheli N, Nosikova I, Rukavishnikov I, Sayenko D, Tomilovskaya E. Impact of different ground-based microgravity models on human sensorimotor system. Front Physiol 2023; 14:1085545. [PMID: 36875039 PMCID: PMC9974674 DOI: 10.3389/fphys.2023.1085545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
This review includes current and updated information about various ground-based microgravity models and their impact on the human sensorimotor system. All known models of microgravity are imperfect in a simulation of the physiological effects of microgravity but have their advantages and disadvantages. This review points out that understanding the role of gravity in motion control requires consideration of data from different environments and in various contexts. The compiled information can be helpful to researchers to effectively plan experiments using ground-based models of the effects of space flight, depending on the problem posed.
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Affiliation(s)
- Alina Saveko
- Russian Federation State Scientific Center—Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russia
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7
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Xiong Z, Tian Y, Wang X, Wei K, Bi Y. Gravity matters for the neural representations of action semantics. Cereb Cortex 2023:6995384. [PMID: 36682884 DOI: 10.1093/cercor/bhad006] [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: 11/28/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/24/2023] Open
Abstract
The dynamic relationship between the neural representation of action word semantics and specific sensorimotor experience remains controversial. Here, we temporarily altered human subjects' sensorimotor experience in a 15-day head-down tilt bed rest setting, a ground-based analog of microgravity that disproportionally affects sensorimotor experiences of the lower limbs, and examined whether such effector-dependent activity deprivation specifically affected the neural processes of comprehending verbs of lower-limb actions (e.g. to kick) relative to upper-limb ones (e.g. to pinch). Using functional magnetic resonance imaging, we compared the multivoxel neural patterns for such action words prior to and after bed rest. We found an effector-specific (lower vs. upper limb) experience modulation in subcortical sensorimotor-related and anterior temporal regions. The neural action semantic representations in other effector-specific verb semantic regions (e.g. left lateral posterior temporal cortex) and motor execution regions were robust against such experience alterations. These effector-specific, sensorimotor-experience-sensitive and experience-independent patterns of verb neural representation highlight the multidimensional and dynamic nature of semantic neural representation, and the broad influence of microgravity (hence gravity) environment on cognition.
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Affiliation(s)
- Ziyi Xiong
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing 100875, China
| | - Yu Tian
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China.,School of Psychological and Cognitive Sciences, Peking University, Beijing 100871, China
| | - Xiaosha Wang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing 100875, China
| | - Kunlin Wei
- School of Psychological and Cognitive Sciences, Peking University, Beijing 100871, China.,Beijing Key Laboratory of Behavior and Mental Health, Beijing 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yanchao Bi
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China.,Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing 100875, China.,Chinese Institute for Brain Research, Beijing 102206, China
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8
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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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9
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Cerebrocortical activation following unilateral labyrinthectomy in mice characterized by whole-brain clearing: implications for sensory reweighting. Sci Rep 2022; 12:15424. [PMID: 36104440 PMCID: PMC9474865 DOI: 10.1038/s41598-022-19678-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 09/01/2022] [Indexed: 11/21/2022] Open
Abstract
Posture and gait are maintained by sensory inputs from the vestibular, visual, and somatosensory systems and motor outputs. Upon vestibular damage, the visual and/or somatosensory systems functionally substitute by cortical mechanisms called “sensory reweighting”. We investigated the cerebrocortical mechanisms underlying sensory reweighting after unilateral labyrinthectomy (UL) in mice. Arc-dVenus transgenic mice, in which the gene encoding the fluorescent protein dVenus is transcribed under the control of the promoter of the immediate early gene Arc, were used in combination with whole-brain three-dimensional (3D) imaging. Performance on the rotarod was measured as a behavioral correlate of sensory reweighting. Following left UL, all mice showed the head roll-tilt until UL10, indicating the vestibular periphery damage. The rotarod performance worsened in the UL mice from UL1 to UL3, which rapidly recovered. Whole-brain 3D imaging revealed that the number of activated neurons in S1, but not in V1, in UL7 was higher than that in sham-treated mice. At UL7, medial prefrontal cortex (mPFC) and agranular insular cortex (AIC) activation was also observed. Therefore, sensory reweighting to the somatosensory system could compensate for vestibular dysfunction following UL; further, mPFC and AIC contribute to the integration of sensory and motor functions to restore balance.
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10
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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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11
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Monitoring the Impact of Spaceflight on the Human Brain. LIFE (BASEL, SWITZERLAND) 2022; 12:life12071060. [PMID: 35888147 PMCID: PMC9323314 DOI: 10.3390/life12071060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/04/2022] [Accepted: 07/07/2022] [Indexed: 11/17/2022]
Abstract
Extended exposure to radiation, microgravity, and isolation during space exploration has significant physiological, structural, and psychosocial effects on astronauts, and particularly their central nervous system. To date, the use of brain monitoring techniques adopted on Earth in pre/post-spaceflight experimental protocols has proven to be valuable for investigating the effects of space travel on the brain. However, future (longer) deep space travel would require some brain function monitoring equipment to be also available for evaluating and monitoring brain health during spaceflight. Here, we describe the impact of spaceflight on the brain, the basic principles behind six brain function analysis technologies, their current use associated with spaceflight, and their potential for utilization during deep space exploration. We suggest that, while the use of magnetic resonance imaging (MRI), positron emission tomography (PET), and computerized tomography (CT) is limited to analog and pre/post-spaceflight studies on Earth, electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and ultrasound are good candidates to be adapted for utilization in the context of deep space exploration.
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12
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Arshad I, Ferrè ER. Express: Cognition in Zero Gravity: Effects of Non-Terrestrial Gravity on Human Behaviour. Q J Exp Psychol (Hove) 2022; 76:979-994. [PMID: 35786100 PMCID: PMC10119906 DOI: 10.1177/17470218221113935] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As humanity prepares for deep space exploration, understanding the impact of spaceflight on bodily physiology is critical. While the effects of non-terrestrial gravity on the body are well established, little is known about its impact on human behaviour and cognition. Astronauts often describe dramatic alterations in sensorimotor functioning, including orientation, postural control and balance. Changes in cognitive functioning as well as in socio-affective processing have also been observed. Here we have reviewed the key literature and explored the impact of non-terrestrial gravity across three key functional domains: sensorimotor, cognition, and socio-affective processing. We have proposed a neuroanatomical model to account for the effects of non-terrestrial gravity in these domains. Understanding the impact of non-terrestrial gravity on human behaviour has never been more timely and it will help mitigate against risks in both commercial and non-commercial spaceflight.
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Affiliation(s)
- Iqra Arshad
- Department of Psychology, Royal Holloway University of London, Egham, UK 3162
| | - Elisa Raffaella Ferrè
- Department of Psychological Sciences, Birkbeck University of London, London, UK 3162
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13
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Jiang S, Qian YIM, Jiang Y, Cao ZQ, Xin BM, Wang YC, Wu B. Effects of 15-Days −6° Head-Down Bed Rest on the Attention Bias of Threatening Stimulus. Front Psychol 2022; 13:730820. [PMID: 35832905 PMCID: PMC9272770 DOI: 10.3389/fpsyg.2022.730820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Previous researchers have found that head-down bed rest (HDBR) will affect the emotional state of individuals, and negative emotions such as anxiety are closely related to attention bias. The present study adopted the dot-probe task to evaluate the effects of 15-days of −6° HDBR on the attention bias of threatening stimulus in 17 young men, which was completed before (Pre-HDBR), during (HDBR-1, HDBR-8, HDBR-15), after (Post-HDBR) the bed rest. In addition, self-report inventories (State Anxiety Inventory, SAI; Positive Affect and Negative Affect Scale, PANAS) were conducted to record emotional changes. The results showed that the participants’ negative affect scores on HDBR-8 were significantly lower than the HDBR-1 in PANAS while there was no significant difference on positive affect scores and anxiety scores in SAI. And the results showed that at the Pre-HDBR, HDBT-1, HDBR-15, Post-HDBR, the response speed to threatening stimulus was faster than neutral stimulus, but no statistical significance. However, reaction time of threatening stimulus is significantly longer than neutral stimulus in the HDBR-8, indicating that HDBR may have an effect on the participants’ attention bias, and this effect is manifested as attention avoidance.
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Affiliation(s)
- Shan Jiang
- Department of Psychology, Beijing Sport University, Beijing, China
| | - YI-Ming Qian
- Department of Psychology, Beijing Sport University, Beijing, China
| | - Yuan Jiang
- China Astronaut Research and Training Center, Beijing, China
| | - Zi-Qin Cao
- China Astronaut Research and Training Center, Beijing, China
| | - Bing-Mu Xin
- Engineering Research Center of Human Circadian Rhythm and Sleep, Shenzhen, China
- Space Science and Technology Institute, Shenzhen, China
| | - Ying-Chun Wang
- Department of Psychology, Beijing Sport University, Beijing, China
- *Correspondence: Ying-Chun Wang,
| | - Bin Wu
- China Astronaut Research and Training Center, Beijing, China
- Bin Wu,
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14
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Wang Y, Zhang X, Wang C, Huang W, Xu Q, Liu D, Zhou W, Chen S, Jiang Y. Modulation of biological motion perception in humans by gravity. Nat Commun 2022; 13:2765. [PMID: 35589705 PMCID: PMC9120521 DOI: 10.1038/s41467-022-30347-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 04/26/2022] [Indexed: 12/02/2022] Open
Abstract
The human visual perceptual system is highly sensitive to biological motion (BM) but less sensitive to its inverted counterpart. This perceptual inversion effect may stem from our selective sensitivity to gravity-constrained life motion signals and confer an adaptive advantage to creatures living on Earth. However, to what extent and how such selective sensitivity is shaped by the Earth’s gravitational field is heretofore unexplored. Taking advantage of a spaceflight experiment and its ground-based analog via 6° head-down tilt bed rest (HDTBR), we show that prolonged microgravity/HDTBR reduces the inversion effect in BM perception. No such change occurs for face perception, highlighting the particular role of gravity in regulating kinematic motion analysis. Moreover, the reduced BM inversion effect is associated with attenuated orientation-dependent neural responses to BM rather than general motion cues and correlated with strengthened functional connectivity between cortical regions dedicated to visual BM processing (i.e., pSTS) and vestibular gravity estimation (i.e., insula). These findings suggest that the neural computation of gravity may act as an embodied constraint, presumably implemented through visuo-vestibular interaction, to sustain the human brain’s selective tuning to life motion signals. Utilizing spaceflight and its ground-based analog, the authors show how the Earth’s gravity sustains the human brain’s orientation-dependent sensitivity to biological motion signals based on neural computations of visual and vestibular gravitational cues.
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Affiliation(s)
- Ying Wang
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Xue Zhang
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China.,Institute of Aviation Human Factors and Cognitive Neuroscience, Department of Aviation Psychology, Flight Technology college, Civil Aviation Flight University of China, Guanghan, China
| | - Chunhui Wang
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China
| | - Weifen Huang
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China
| | - Qian Xu
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Dong Liu
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Wen Zhou
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Shanguang Chen
- National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China. .,China Manned Space Agency, Beijing, China.
| | - Yi Jiang
- State Key Laboratory of Brain and Cognitive Sciences, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China. .,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China. .,Chinese Institute for Brain Research, Beijing, China. .,Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China.
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15
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Tays GD, McGregor HR, Lee JK, Beltran N, Kofman IS, De Dios YE, Mulder E, Bloomberg JJ, Mulavara AP, Wood SJ, Seidler RD. The Effects of 30 Minutes of Artificial Gravity on Cognitive and Sensorimotor Performance in a Spaceflight Analog Environment. Front Neural Circuits 2022; 16:784280. [PMID: 35310547 PMCID: PMC8924040 DOI: 10.3389/fncir.2022.784280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/24/2022] [Indexed: 11/30/2022] Open
Abstract
The altered vestibular signaling and somatosensory unloading of microgravity result in sensory reweighting and adaptation to conflicting sensory inputs. Aftereffects of these adaptive changes are evident postflight as impairments in behaviors such as balance and gait. Microgravity also induces fluid shifts toward the head and an upward shift of the brain within the skull; these changes are well-replicated in strict head-down tilt bed rest (HDBR), a spaceflight analog environment. Artificial gravity (AG) is a potential countermeasure to mitigate these effects of microgravity. A previous study demonstrated that intermittent (six, 5-mins bouts per day) daily AG sessions were more efficacious at counteracting orthostatic intolerance in a 5 day HDBR study than continuous daily AG. Here we examined whether intermittent daily AG was also more effective than continuous dosing for mitigating brain and behavioral changes in response to 60 days of HDBR. Participants (n = 24) were split evenly between three groups. The first received 30 mins of continuous AG daily (cAG). The second received 30 mins of intermittent AG daily (6 bouts of 5 mins; iAG). The third received no AG (Ctrl). We collected a broad range of sensorimotor, cognitive, and brain structural and functional assessments before, during, and after the 60 days of HDBR. We observed no significant differences between the three groups in terms of HDBR-associated changes in cognition, balance, and functional mobility. Interestingly, the intermittent AG group reported less severe motion sickness symptoms than the continuous group during centrifugation; iAG motion sickness levels were not elevated above those of controls who did not undergo AG. They also had a shorter duration of post-AG illusory motion than cAG. Moreover, the two AG groups performed the paced auditory serial addition test weekly while undergoing AG; their performance was more accurate than that of controls, who performed the test while in HDBR. Although AG did not counteract HDBR-induced gait and balance declines, iAG did not cause motion sickness and was associated with better self-motion perception during AG ramp-down. Additionally, both AG groups had superior cognitive performance while undergoing AG relative to controls; this may reflect attention or motivation differences between the groups.
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Affiliation(s)
- Grant D. Tays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Heather R. McGregor
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | | | | | | | | | | | | | | | - Scott J. Wood
- NASA Johnson Space Center, Houston, TX, United States
| | - Rachael 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
- *Correspondence: Rachael D. Seidler,
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16
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Russo M, Ozeri-Engelhard N, Hupfeld K, Nettekoven C, Thibault S, Sedaghat-Nejad E, Buchwald D, Xing D, Zobeiri O, Kilteni K, Albert ST, Ariani G. Highlights from the 30th Annual Meeting of the Society for the Neural Control of Movement. J Neurophysiol 2021; 126:967-975. [PMID: 34406885 PMCID: PMC8560412 DOI: 10.1152/jn.00334.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 11/22/2022] Open
Affiliation(s)
- Marta Russo
- Department of Neurology, Tor Vergata Polyclinic, Rome, Italy
- Department of Biology, Northeastern University, Boston, Massachusetts
| | - Nofar Ozeri-Engelhard
- WM Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Kathleen Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Caroline Nettekoven
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Department of Psychiatry, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Simon Thibault
- ImpAct team, Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR5292, University of Lyon 1, Lyon, France
| | - Ehsan Sedaghat-Nejad
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Daniela Buchwald
- Ottobock SE & Co. KGaA, Software & Electronics Engineering, Duderstadt, Germany
| | - David Xing
- Department of Neurobiology, Northwestern University, Evanston, Illinois
| | - Omid Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | | | - Scott T Albert
- Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Giacomo Ariani
- The Brain and Mind Institute, Western University, London, Ontario, Canada
- Department of Computer Science, Western University, London, Ontario, Canada
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17
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Mahadevan AD, Hupfeld KE, Lee JK, De Dios YE, Kofman IS, Beltran NE, Mulder E, Bloomberg JJ, Mulavara AP, Seidler RD. Head-Down-Tilt Bed Rest With Elevated CO 2: Effects of a Pilot Spaceflight Analog on Neural Function and Performance During a Cognitive-Motor Dual Task. Front Physiol 2021; 12:654906. [PMID: 34512371 PMCID: PMC8424013 DOI: 10.3389/fphys.2021.654906] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 07/08/2021] [Indexed: 11/16/2022] Open
Abstract
Spaceflight has widespread effects on human performance, including on the ability to dual task. Here, we examine how a spaceflight analog comprising 30 days of head-down-tilt bed rest (HDBR) combined with 0.5% ambient CO2 (HDBR + CO2) influences performance and functional activity of the brain during single and dual tasking of a cognitive and a motor task. The addition of CO2 to HDBR is thought to better mimic the conditions aboard the International Space Station. Participants completed three tasks: (1) COUNT: counting the number of times an oddball stimulus was presented among distractors; (2) TAP: tapping one of two buttons in response to a visual cue; and (3) DUAL: performing both tasks concurrently. Eleven participants (six males) underwent functional MRI (fMRI) while performing these tasks at six time points: twice before HDBR + CO2, twice during HDBR + CO2, and twice after HDBR + CO2. Behavioral measures included reaction time, standard error of reaction time, and tapping accuracy during the TAP and DUAL tasks, and the dual task cost (DTCost) of each of these measures. We also quantified DTCost of fMRI brain activation. In our previous HDBR study of 13 participants (with atmospheric CO2), subjects experienced TAP accuracy improvements during bed rest, whereas TAP accuracy declined while in the current study of HDBR + CO2. In the HDBR + CO2 subjects, we identified a region in the superior frontal gyrus that showed decreased DTCost of brain activation while in HDBR + CO2, and recovered back to baseline levels before the completion of bed rest. Compared to HDBR alone, we found different patterns of brain activation change with HDBR + CO2. HDBR + CO2 subjects had increased DTCost in the middle temporal gyrus whereas HDBR subjects had decreased DTCost in the same area. Five of the HDBR + CO2 subjects developed signs of spaceflight-associated neuro-ocular syndrome (SANS). These subjects exhibited lower baseline dual task activation and higher slopes of change during HDBR + CO2 than subjects with no signs of SANS. Collectively, this pilot study provides insight into the additional and/or interactive effects of CO2 levels during HDBR, and information regarding the impacts of this spaceflight analog environment on the neural correlates of dual tasking.
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Affiliation(s)
- Aditya D. Mahadevan
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
- College of Medicine, University of Florida, Gainesville, FL, United States
| | - Kathleen E. Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - 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, FL, United States
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
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18
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Hupfeld KE, McGregor HR, Koppelmans V, Beltran NE, Kofman IS, De Dios YE, Riascos RF, Reuter-Lorenz PA, Wood SJ, Bloomberg JJ, Mulavara AP, Seidler RD. Brain and Behavioral Evidence for Reweighting of Vestibular Inputs with Long-Duration Spaceflight. Cereb Cortex 2021; 32:755-769. [PMID: 34416764 DOI: 10.1093/cercor/bhab239] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/14/2022] Open
Abstract
Microgravity alters vestibular signaling. In-flight adaptation to altered vestibular afferents is reflected in post-spaceflight aftereffects, evidenced by declines in vestibularly mediated behaviors (e.g., walking/standing balance), until readaptation to Earth's 1G environment occurs. Here we examine how spaceflight affects neural processing of applied vestibular stimulation. We used fMRI to measure brain activity in response to vestibular stimulation in 15 astronauts pre- and post-spaceflight. We also measured vestibularly-mediated behaviors, including balance, mobility, and rod-and-frame test performance. Data were collected twice preflight and four times postflight. As expected, vestibular stimulation at the preflight sessions elicited activation of the parietal opercular area ("vestibular cortex") and deactivation of somatosensory and visual cortices. Pre- to postflight, we found widespread reductions in this somatosensory and visual cortical deactivation, supporting sensory compensation and reweighting with spaceflight. These pre- to postflight changes in brain activity correlated with changes in eyes closed standing balance, and greater pre- to postflight reductions in deactivation of the visual cortices associated with less postflight balance decline. The observed brain changes recovered to baseline values by 3 months postflight. Together, these findings provide evidence for sensory reweighting and adaptive cortical neuroplasticity with spaceflight. These results have implications for better understanding compensation and adaptation to vestibular functional disruption.
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Affiliation(s)
- 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
| | - V Koppelmans
- Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
| | | | | | | | - R F Riascos
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - P A Reuter-Lorenz
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - 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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19
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Salazar AP, Hupfeld KE, Lee JK, Banker LA, Tays GD, Beltran NE, Kofman IS, De Dios YE, Mulder E, Bloomberg JJ, Mulavara AP, Seidler RD. Visuomotor Adaptation Brain Changes During a Spaceflight Analog With Elevated Carbon Dioxide (CO 2): A Pilot Study. Front Neural Circuits 2021; 15:659557. [PMID: 34163332 PMCID: PMC8215599 DOI: 10.3389/fncir.2021.659557] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/11/2021] [Indexed: 12/28/2022] Open
Abstract
Astronauts on board the International Space Station (ISS) must adapt to several environmental challenges including microgravity, elevated carbon dioxide (CO2), and isolation while performing highly controlled movements with complex equipment. Head down tilt bed rest (HDBR) is an analog used to study spaceflight factors including body unloading and headward fluid shifts. We recently reported how HDBR with elevated CO2 (HDBR+CO2) affects visuomotor adaptation. Here we expand upon this work and examine the effects of HDBR+CO2 on brain activity during visuomotor adaptation. Eleven participants (34 ± 8 years) completed six functional MRI (fMRI) sessions pre-, during, and post-HDBR+CO2. During fMRI, participants completed a visuomotor adaptation task, divided into baseline, early, late and de-adaptation. Additionally, we compare brain activity between this NASA campaign (30-day HDBR+CO2) and a different campaign with a separate set of participants (60-day HDBR with normal atmospheric CO2 levels, n = 8; 34.25 ± 7.9 years) to characterize the specific effects of CO2. Participants were included by convenience. During early adaptation across the HDBR+CO2 intervention, participants showed decreasing activation in temporal and subcortical brain regions, followed by post- HDBR+CO2 recovery. During late adaptation, participants showed increasing activation in the right fusiform gyrus and right caudate nucleus during HDBR+CO2; this activation normalized to baseline levels after bed rest. There were no correlations between brain changes and adaptation performance changes from pre- to post HDBR+CO2. Also, there were no statistically significant differences between the HDBR+CO2 group and the HDBR controls, suggesting that changes in brain activity were due primarily to bed rest rather than elevated CO2. Five HDBR+CO2 participants presented with optic disc edema, a sign of Spaceflight Associated Neuro-ocular Syndrome (SANS). An exploratory analysis of HDBR+CO2 participants with and without signs of SANS revealed no group differences in brain activity during any phase of the adaptation task. Overall, these findings have implications for spaceflight missions and training, as ISS missions require individuals to adapt to altered sensory inputs over long periods in space. Further, this is the first study to verify the HDBR and elevated CO2 effects on the neural correlates of visuomotor adaptation.
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Affiliation(s)
- Ana Paula Salazar
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Kathleen E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Jessica K Lee
- DLR (Deutsches Zentrum für Luft- und Raumfahrt), Cologne, Germany
| | - Lauren A Banker
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Grant D Tays
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | | | | | | | - Edwin Mulder
- DLR (Deutsches Zentrum für Luft- und Raumfahrt), Cologne, Germany
| | | | | | - Rachael 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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20
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Brauns K, Friedl-Werner A, Gunga HC, Stahn AC. Effects of two months of bed rest and antioxidant supplementation on attentional processing. Cortex 2021; 141:81-93. [PMID: 34044245 DOI: 10.1016/j.cortex.2021.03.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/05/2021] [Accepted: 03/25/2021] [Indexed: 12/18/2022]
Abstract
Physical inactivity across the lifespan is a growing public health concern affecting the cardiovascular, musculoskeletal, and central nervous system. Data on the effects of dietary antioxidants as neuroprotective treatments when physical activity levels are impaired are lacking. In this randomized controlled study, twenty young healthy men underwent 60 days of bed rest. Participants were randomly assigned to a treatment group (n = 10) receiving a daily antioxidant supplement comprising polyphenols, omega-3 fatty acids, vitamin E, and selenium or a control group (n = 10). Event-related potentials (ERPs) and behavioral data from a three-stimulus oddball paradigm were collected eight days before bed rest, after 60 days of immobilization, and after eight days of recovery. After two months of bed rest, we found a significant decrease in task efficiency irrespective of the treatment that was corroborated by lower ERPs in fronto-central and parietal brain regions. Neither behavioral nor electrocortical data returned to baseline values after eight days of recovery. Our results provide support for the adverse and persistent neurobehavioral effects of prolonged bed rest, which could not be mitigated by antioxidant supplementation. These findings raise important implications for situations in which physical activity levels become severely restricted such as medical conditions or sedentary lifestyles.
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Affiliation(s)
- Katharina Brauns
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Physiology, Berlin, Germany
| | - Anika Friedl-Werner
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Physiology, Berlin, Germany; Université de Normandie, INSERM U 1075 COMETE, Caen, France
| | - Hanns-Christian Gunga
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Physiology, Berlin, Germany
| | - Alexander C Stahn
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Institute of Physiology, Berlin, Germany; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19004, USA.
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21
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Lee JK, Koppelmans V, Pasternak O, Beltran NE, Kofman IS, De Dios YE, Mulder ER, Mulavara AP, Bloomberg JJ, Seidler RD. Effects of Spaceflight Stressors on Brain Volume, Microstructure, and Intracranial Fluid Distribution. Cereb Cortex Commun 2021; 2:tgab022. [PMID: 34296167 PMCID: PMC8152913 DOI: 10.1093/texcom/tgab022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/02/2021] [Accepted: 03/26/2021] [Indexed: 11/25/2022] Open
Abstract
Astronauts are exposed to elevated CO2 levels onboard the International Space Station. Here, we investigated structural brain changes in 11 participants following 30-days of head-down tilt bed rest (HDBR) combined with 0.5% ambient CO2 (HDBR + CO2) as a spaceflight analog. We contrasted brain changes observed in the HDBR + CO2 group with those of a previous HDBR sample not exposed to elevated CO2. Both groups exhibited a global upward shift of the brain and concomitant intracranial free water (FW) redistribution. Greater gray matter changes were seen in the HDBR + CO2 group in some regions. The HDBR + CO2 group showed significantly greater FW decrements in the posterior cerebellum and the cerebrum than the HDBR group. In comparison to the HDBR group, the HDBR + CO2 group exhibited greater diffusivity increases. In half of the participants, the HDBR + CO2 intervention resulted in signs of Spaceflight Associated Neuro-ocular Syndrome (SANS), a constellation of ocular structural and functional changes seen in astronauts. We therefore conducted an exploratory comparison compared between subjects that did and did not develop SANS and found asymmetric lateral ventricle enlargement in the SANS group. These results enhance our understanding of the underlying mechanisms of spaceflight-induced brain changes, which is critical for promoting astronaut health and performance.
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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 32611, USA
| | - Vincent Koppelmans
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA
| | - Ofer Pasternak
- Deparments of Psychiatry and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | - Edwin R Mulder
- Institute of Aerospace Medicine, 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 32611, USA
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22
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Brauns K, Friedl-Werner A, Maggioni MA, Gunga HC, Stahn AC. Head-Down Tilt Position, but Not the Duration of Bed Rest Affects Resting State Electrocortical Activity. Front Physiol 2021; 12:638669. [PMID: 33716785 PMCID: PMC7951060 DOI: 10.3389/fphys.2021.638669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/28/2021] [Indexed: 11/13/2022] Open
Abstract
Adverse cognitive and behavioral conditions and psychiatric disorders are considered a critical and unmitigated risk during future long-duration space missions (LDSM). Monitoring and mitigating crew health and performance risks during these missions will require tools and technologies that allow to reliably assess cognitive performance and mental well-being. Electroencephalography (EEG) has the potential to meet the technical requirements for the non-invasive and objective monitoring of neurobehavioral conditions during LDSM. Weightlessness is associated with fluid and brain shifts, and these effects could potentially challenge the interpretation of resting state EEG recordings. Head-down tilt bed rest (HDBR) provides a unique spaceflight analog to study these effects on Earth. Here, we present data from two long-duration HDBR experiments, which were used to systematically investigate the time course of resting state electrocortical activity during prolonged HDBR. EEG spectral power significantly reduced within the delta, theta, alpha, and beta frequency bands. Likewise, EEG source localization revealed significantly lower activity in a broad range of centroparietal and occipital areas within the alpha and beta frequency domains. These changes were observed shortly after the onset of HDBR, did not change throughout HDBR, and returned to baseline after the cessation of bed rest. EEG resting state functional connectivity was not affected by HDBR. The results provide evidence for a postural effect on resting state brain activity that persists throughout long-duration HDBR, indicating that immobilization and inactivity per se do not affect resting state electrocortical activity during HDBR. Our findings raise an important issue on the validity of EEG to identify the time course of changes in brain function during prolonged HBDR, and highlight the importance to maintain a consistent body posture during all testing sessions, including data collections at baseline and recovery.
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Affiliation(s)
- Katharina Brauns
- Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany
| | - Anika Friedl-Werner
- Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany.,INSERM U 1075 COMETE, Université de Normandie, Caen, France
| | - Martina A Maggioni
- Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany.,Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Hanns-Christian Gunga
- Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany
| | - Alexander C Stahn
- Charité - Universitätsmedizin Berlin, a corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Physiology, Berlin, Germany.,Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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23
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Roy-O'Reilly M, Mulavara A, Williams T. A review of alterations to the brain during spaceflight and the potential relevance to crew in long-duration space exploration. NPJ Microgravity 2021; 7:5. [PMID: 33594073 PMCID: PMC7887220 DOI: 10.1038/s41526-021-00133-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
During spaceflight, the central nervous system (CNS) is exposed to a complex array of environmental stressors. However, the effects of long-duration spaceflight on the CNS and the resulting impact to crew health and operational performance remain largely unknown. In this review, we summarize the current knowledge regarding spaceflight-associated changes to the brain as measured by magnetic resonance imaging, particularly as they relate to mission duration. Numerous studies have reported macrostructural changes to the brain after spaceflight, including alterations in brain position, tissue volumes and cerebrospinal fluid distribution and dynamics. Changes in brain tissue microstructure and connectivity were also described, involving regions related to vestibular, cerebellar, visual, motor, somatosensory and cognitive function. Several alterations were also associated with exposure to analogs of spaceflight, providing evidence that brain changes likely result from cumulative exposure to multiple independent environmental stressors. Whereas several studies noted that changes to the brain become more pronounced with increasing mission duration, it remains unclear if these changes represent compensatory phenomena or maladaptive dysregulations. Future work is needed to understand how spaceflight-associated changes to the brain affect crew health and performance, with the goal of developing comprehensive monitoring and countermeasure strategies for future long-duration space exploration.
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Affiliation(s)
- Meaghan Roy-O'Reilly
- Department of Neurology, University of Texas Health Science Center, Houston, TX, USA.
- Department of Medicine, Stanford University Medical Center, Stanford, CA, USA.
| | | | - Thomas Williams
- National Aeronautics and Space Administration, Johnson Space Center, Houston, TX, USA
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24
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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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25
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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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26
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Ralston JD, Raina A, Benson BW, Peters RM, Roper JM, Ralston AB. Physiological Vibration Acceleration (Phybrata) Sensor Assessment of Multi-System Physiological Impairments and Sensory Reweighting Following Concussion. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2020; 13:411-438. [PMID: 33324120 PMCID: PMC7733539 DOI: 10.2147/mder.s279521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/02/2020] [Indexed: 11/23/2022] Open
Abstract
Objective To assess the utility of a head-mounted wearable inertial motion unit (IMU)-based physiological vibration acceleration (“phybrata”) sensor to support the clinical diagnosis of concussion, classify and quantify specific concussion-induced physiological system impairments and sensory reweighting, and track individual patient recovery trajectories. Methods Data were analyzed from 175 patients over a 12-month period at three clinical sites. Comprehensive clinical concussion assessments were first completed for all patients, followed by testing with the phybrata sensor. Phybrata time series data and spatial scatter plots, eyes open (Eo) and eyes closed (Ec) phybrata powers, average power (Eo+Ec)/2, Ec/Eo phybrata power ratio, time-resolved phybrata spectral density (TRPSD) distributions, and receiver operating characteristic (ROC) curves are compared for individuals with no objective impairments and those clinically diagnosed with concussions and accompanying vestibular impairment, other neurological impairment, or both vestibular and neurological impairments. Finally, pre- and post-injury phybrata case report results are presented for a participant who was diagnosed with a concussion and subsequently monitored during treatment, rehabilitation, and return-to-activity clearance. Results Phybrata data demonstrate distinct features and patterns for individuals with no discernable clinical impairments, diagnosed vestibular pathology, and diagnosed neurological pathology. ROC curves indicate that the average power (Eo+Ec)/2 may be utilized to support clinical diagnosis of concussion, while Eo and Ec/Eo may be utilized as independent measures to confirm accompanying neurological and vestibular impairments, respectively. All 3 measures demonstrate area under the curve (AUC), sensitivity, and specificity above 90% for their respective diagnoses. Phybrata spectral analyses demonstrate utility for quantifying the severity of concussion-induced physiological impairments, sensory reweighting, and subsequent monitoring of improvements throughout treatment and rehabilitation. Conclusion Phybrata testing assists with objective concussion diagnosis and provides an important adjunct to standard concussion assessment tools by objectively ascertaining neurological and vestibular impairments, guiding targeted rehabilitation strategies, monitoring recovery, and assisting with return-to-sport/work/learn decision-making.
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Affiliation(s)
| | - Ashutosh Raina
- Center of Excellence for Pediatric Neurology, Rocklin, CA 95765, USA.,Concussion Medical Clinic, Rocklin, CA 95765, USA
| | - Brian W Benson
- Benson Concussion Institute, Calgary, Alberta T3B 6B7, Canada.,Canadian Sport Institute Calgary, Calgary, Alberta T3B 5R5, Canada
| | - Ryan M Peters
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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27
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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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28
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Salazar AP, Hupfeld KE, Lee JK, Beltran NE, Kofman IS, De Dios YE, Mulder E, Bloomberg JJ, Mulavara AP, Seidler RD. Neural Working Memory Changes During a Spaceflight Analog With Elevated Carbon Dioxide: A Pilot Study. Front Syst Neurosci 2020; 14:48. [PMID: 32848641 PMCID: PMC7399639 DOI: 10.3389/fnsys.2020.00048] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
Spaceflight missions to the International Space Station (ISS) expose astronauts to microgravity, radiation, isolation, and elevated carbon dioxide (CO2), among other factors. Head down tilt bed rest (HDBR) is an Earth-based analog for spaceflight used to study body unloading, fluid shifts, and other factors unrelated to gravitational changes. While in space, astronauts need to use mental rotation strategies to facilitate their adaptation to the ISS environment. Therefore, spatial working memory is essential for crewmember performance. Although the effects of HDBR on spatial working memory have recently been studied, the results are still inconclusive. Here, we expand upon past work and examine the effects of HDBR with elevated CO2 (HDBR + CO2) on brain activation patterns during spatial working memory performance. In addition, we compare brain activation between 30 days of HDBR + CO2 and 70 days of HDBR to test the isolated effect of CO2. Eleven subjects (6 males, 5 females; mean age = 34 ± 8 years) underwent six functional magnetic resonance imaging (fMRI) sessions pre-, during, and post-HDBR + CO2. During the HDBR + CO2 intervention, we observed decreasing activation in the right middle frontal gyrus and left regions of the cerebellum, followed by post-intervention recovery. We detected several correlations between brain and behavioral slopes of change with the HDBR + CO2 intervention. For example, greater increases in activation in frontal, temporal and parietal regions were associated with larger spatial working memory improvements. Comparing the HDBR + CO2 group to data from our previous 70-day HDBR study, we found greater decreases in activation in the right hippocampus and left inferior temporal gyrus for the HDBR + CO2 group over the course of the intervention. Together, these findings increase our understanding of the neural mechanisms of HDBR, elevated levels of CO2 and spaceflight-related changes in spatial working memory performance.
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Affiliation(s)
- Ana Paula Salazar
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Kathleen E Hupfeld
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - 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, FL, United States.,Department of Neurology, University of Florida, Gainesville, FL, United States
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29
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Helmchen C, Machner B, Rother M, Spliethoff P, Göttlich M, Sprenger A. Effects of galvanic vestibular stimulation on resting state brain activity in patients with bilateral vestibulopathy. Hum Brain Mapp 2020; 41:2527-2547. [PMID: 32103579 PMCID: PMC7267973 DOI: 10.1002/hbm.24963] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 01/04/2023] Open
Abstract
We examined the effect of galvanic vestibular stimulation (GVS) on resting state brain activity using fMRI (rs‐fMRI) in patients with bilateral vestibulopathy. Based on our previous findings, we hypothesized that GVS, which excites the vestibular nerve fibers, (a) increases functional connectivity in temporoparietal regions processing vestibular signals, and (b) alleviates abnormal visual–vestibular interaction. Rs‐fMRI of 26 patients and 26 age‐matched healthy control subjects was compared before and after GVS. The stimulation elicited a motion percept in all participants. Using different analyses (degree centrality, DC; fractional amplitude of low frequency fluctuations [fALFF] and seed‐based functional connectivity, FC), group comparisons revealed smaller rs‐fMRI in the right Rolandic operculum of patients. After GVS, rs‐fMRI increased in the right Rolandic operculum in both groups and in the patients' cerebellar Crus 1 which was related to vestibular hypofunction. GVS elicited a fALFF increase in the visual cortex of patients that was inversely correlated with the patients' rating of perceived dizziness. After GVS, FC between parietoinsular cortex and higher visual areas increased in healthy controls but not in patients. In conclusion, short‐term GVS is able to modulate rs‐fMRI in healthy controls and BV patients. GVS elicits an increase of the reduced rs‐fMRI in the patients' right Rolandic operculum, which may be an important contribution to restore the disturbed visual–vestibular interaction. The GVS‐induced changes in the cerebellum and the visual cortex were associated with lower dizziness‐related handicaps in patients, possibly reflecting beneficial neural plasticity that might subserve visual–vestibular compensation of deficient self‐motion perception.
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Affiliation(s)
- Christoph Helmchen
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Björn Machner
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Matthias Rother
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Peer Spliethoff
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Martin Göttlich
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany
| | - Andreas Sprenger
- Department of Neurology, University Hospitals Schleswig-Holstein, Lübeck, Germany.,Institute of Psychology II, University of Lübeck, Lübeck, Germany
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30
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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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31
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Dixon JB, Clark TK. Sensorimotor impairment from a new analog of spaceflight-altered neurovestibular cues. J Neurophysiol 2020; 123:209-223. [PMID: 31747329 DOI: 10.1152/jn.00156.2019] [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: 11/22/2022] Open
Abstract
Exposure to microgravity during spaceflight causes central reinterpretations of orientation sensory cues in astronauts, leading to sensorimotor impairment upon return to Earth. Currently there is no ground-based analog for the neurovestibular system relevant to spaceflight. We propose such an analog, which we term the "wheelchair head-immobilization paradigm" (WHIP). Subjects lie on their side on a bed fixed to a modified electric wheelchair, with their head restrained by a custom facemask. WHIP prevents any head tilt relative to gravity, which normally produces coupled stimulation to the otoliths and semicircular canals, but does not occur in microgravity. Decoupled stimulation is produced through translation and rotation on the wheelchair by the subject using a joystick. Following 12 h of WHIP exposure, subjects systematically felt illusory sensations of self-motion when making head tilts and had significant decrements in balance and locomotion function using tasks similar to those assessed in astronauts postspaceflight. These effects were not observed in our control groups without head restraint, suggesting the altered neurovestibular stimulation patterns experienced in WHIP lead to relevant central reinterpretations. We conclude by discussing the findings in light of postspaceflight sensorimotor impairment, WHIP's uses beyond a spaceflight analog, limitations, and future work.NEW & NOTEWORTHY We propose, implement, and demonstrate the feasibility of a new analog for spaceflight-altered neurovestibular stimulation. Following extended exposure to the analog, we found subjects reported illusory self-motion perception. Furthermore, they demonstrated decrements in balance and locomotion, using tasks similar to those used to assess astronaut sensorimotor performance postspaceflight.
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Affiliation(s)
- Jordan B Dixon
- Smead Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado
| | - Torin K Clark
- Smead Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado
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32
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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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33
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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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34
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Herold F, Törpel A, Schega L, Müller NG. Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements - a systematic review. Eur Rev Aging Phys Act 2019; 16:10. [PMID: 31333805 PMCID: PMC6617693 DOI: 10.1186/s11556-019-0217-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/26/2019] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND During the aging process, physical capabilities (e.g., muscular strength) and cognitive functions (e.g., memory) gradually decrease. Regarding cognitive functions, substantial functional (e.g., compensatory brain activity) and structural changes (e.g., shrinking of the hippocampus) in the brain cause this decline. Notably, growing evidence points towards a relationship between cognition and measures of muscular strength and muscle mass. Based on this emerging evidence, resistance exercises and/or resistance training, which contributes to the preservation and augmentation of muscular strength and muscle mass, may trigger beneficial neurobiological processes and could be crucial for healthy aging that includes preservation of the brain and cognition. Compared with the multitude of studies that have investigated the influence of endurance exercises and/or endurance training on cognitive performance and brain structure, considerably less work has focused on the effects of resistance exercises and/or resistance training. While the available evidence regarding resistance exercise-induced changes in cognitive functions is pooled, the underlying neurobiological processes, such as functional and structural brain changes, have yet to be summarized. Hence, the purpose of this systematic review is to provide an overview of resistance exercise-induced functional and/or structural brain changes that are related to cognitive functions. METHODS AND RESULTS A systematic literature search was conducted by two independent researchers across six electronic databases; 5957 records were returned, of which 18 were considered relevant and were analyzed. SHORT CONCLUSION Based on our analyses, resistance exercises and resistance training evoked substantial functional brain changes, especially in the frontal lobe, which were accompanied by improvements in executive functions. Furthermore, resistance training led to lower white matter atrophy and smaller white matter lesion volumes. However, based on the relatively small number of studies available, the findings should be interpreted cautiously. Hence, future studies are required to investigate the underlying neurobiological mechanisms and to verify whether the positive findings can be confirmed and transferred to other needy cohorts, such as older adults with dementia, sarcopenia and/or dynapenia.
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Affiliation(s)
- Fabian Herold
- Research Group Neuroprotection, German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Alexander Törpel
- Institute III, Department of Sport Science, Otto von Guericke University Magdeburg, Zschokkestr. 32, 39104 Magdeburg, Germany
| | - Lutz Schega
- Institute III, Department of Sport Science, Otto von Guericke University Magdeburg, Zschokkestr. 32, 39104 Magdeburg, Germany
| | - Notger G. Müller
- Research Group Neuroprotection, German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Brenneckestraße 6, 39118 Magdeburg, Germany
- Department of Neurology, Medical Faculty, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
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35
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Pechenkova E, Nosikova I, Rumshiskaya A, Litvinova L, Rukavishnikov I, Mershina E, Sinitsyn V, Van Ombergen A, Jeurissen B, Jillings S, Laureys S, Sijbers J, Grishin A, Chernikova L, Naumov I, Kornilova L, Wuyts FL, Tomilovskaya E, Kozlovskaya I. Alterations of Functional Brain Connectivity After Long-Duration Spaceflight as Revealed by fMRI. Front Physiol 2019; 10:761. [PMID: 31333476 PMCID: PMC6621543 DOI: 10.3389/fphys.2019.00761] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 05/31/2019] [Indexed: 12/22/2022] Open
Abstract
The present study reports alterations of task-based functional brain connectivity in a group of 11 cosmonauts after a long-duration spaceflight, compared to a healthy control group not involved in the space program. To elicit the postural and locomotor sensorimotor mechanisms that are usually most significantly impaired when space travelers return to Earth, a plantar stimulation paradigm was used in a block design fMRI study. The motor control system activated by the plantar stimulation involved the pre-central and post-central gyri, SMA, SII/operculum, and, to a lesser degree, the insular cortex and cerebellum. While no post-flight alterations were observed in terms of activation, the network-based statistics approach revealed task-specific functional connectivity modifications within a broader set of regions involving the activation sites along with other parts of the sensorimotor neural network and the visual, proprioceptive, and vestibular systems. The most notable findings included a post-flight increase in the stimulation-specific connectivity of the right posterior supramarginal gyrus with the rest of the brain; a strengthening of connections between the left and right insulae; decreased connectivity of the vestibular nuclei, right inferior parietal cortex (BA40) and cerebellum with areas associated with motor, visual, vestibular, and proprioception functions; and decreased coupling of the cerebellum with the visual cortex and the right inferior parietal cortex. The severity of space motion sickness symptoms was found to correlate with a post- to pre-flight difference in connectivity between the right supramarginal gyrus and the left anterior insula. Due to the complex nature and rapid dynamics of adaptation to gravity alterations, the post-flight findings might be attributed to both the long-term microgravity exposure and to the readaptation to Earth's gravity that took place between the landing and post-flight MRI session. Nevertheless, the results have implications for the multisensory reweighting and gravitational motor system theories, generating hypotheses to be tested in future research.
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Affiliation(s)
| | - Inna Nosikova
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Alena Rumshiskaya
- Radiology Department, Federal Center of Treatment and Rehabilitation, Moscow, Russia
| | - Liudmila Litvinova
- Radiology Department, Federal Center of Treatment and Rehabilitation, Moscow, Russia
| | - Ilya Rukavishnikov
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Elena Mershina
- Medical Research and Educational Center, Lomonosov Moscow State University, Moscow, Russia
| | - Valentin Sinitsyn
- Medical Research and Educational Center, Lomonosov Moscow State University, Moscow, Russia
| | - Angelique Van Ombergen
- Lab for Equilibrium Investigations and Aerospace, Faculty of Science, University of Antwerp, Antwerp, Belgium
| | - Ben Jeurissen
- iMec/Vision Lab, Faculty of Science, University of Antwerp, Antwerp, Belgium
| | - Steven Jillings
- Lab for Equilibrium Investigations and Aerospace, Faculty of Science, University of Antwerp, Antwerp, Belgium
- Coma Science Group, GIGA Consciousness Research Centre, Neurology Department, University Hospital of Liège, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA Consciousness Research Centre, Neurology Department, University Hospital of Liège, Liège, Belgium
| | - Jan Sijbers
- iMec/Vision Lab, Faculty of Science, University of Antwerp, Antwerp, Belgium
| | | | - Ludmila Chernikova
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Ivan Naumov
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Ludmila Kornilova
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Floris L. Wuyts
- Lab for Equilibrium Investigations and Aerospace, Faculty of Science, University of Antwerp, Antwerp, Belgium
| | - Elena Tomilovskaya
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Inessa Kozlovskaya
- Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
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36
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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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37
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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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38
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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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