Menu

 

The NASA Task Book
Advanced Search     

Project Title:  Bed Rest as a Spaceflight Analog to Study Neurocognitive Changes: Extent, Longevity, and Neural Bases Reduce
Fiscal Year: FY 2016 
Division: Human Research 
Research Discipline/Element:
HRP BHP:Behavioral Health & Performance (archival in 2017)
Start Date: 08/01/2012  
End Date: 12/31/2015  
Task Last Updated: 05/18/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Seidler, Rachael D. Ph.D. / University of Florida 
Address:  Applied Physiology & Kinesiology 
FLG 142, P.O. Box 118205 
Gainesville , FL 32611-8205 
Email: rachaelseidler@ufl.edu 
Phone: 352-294-1722  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Florida 
Joint Agency:  
Comments: NOTE: PI moved to University of Florida in July 2017; previous affiliation was University of Michigan.  
Co-Investigator(s)
Affiliation: 
Mulavara, Ajitkumar  Universities Space Research Association 
Wood, Scott  Azusa Pacific University 
Project Information: Grant/Contract No. NCC 9-58-SA02802 
Responsible Center: NSBRI 
Grant Monitor:  
Center Contact:   
Solicitation / Funding Source: 2011 Crew Health NNJ11ZSA002NA 
Grant/Contract No.: NCC 9-58-SA02802 
Project Type: GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Human Research Program Elements: (1) BHP:Behavioral Health & Performance (archival in 2017)
Human Research Program Risks: (1) Bmed:Risk of Adverse Behavioral Conditions and Psychiatric Disorders
(2) HCI:Risk of Inadequate Human-Computer Interaction
(3) Muscle:Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance
(4) Sensorimotor:Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks (Revised as of IRP Rev M)
Human Research Program Gaps: (1) BMed03:We need to identify and quantify the key threats to and promoters of mission relevant behavioral health and performance during autonomous, long duration and/or long distance exploration missions (IRP Rev F)
(2) SHFE-HCI-03:We need HCI guidelines (e.g., display configuration, screen-navigation) to mitigate the performance decrements identified in SHFE-HCI-08 due to the spaceflight environment (IRP Rev D)
(3) SM26:Determine if exposure to long-duration spaceflight leads to neural structural alterations and if this remodeling impacts cognitive and functional performance (IRP Rev F)
(4) SM7.1:Determine if there are decrements in performance on functional tasks after long-duration spaceflight. Determine how changes in physiological function, exercise activity, and/or clinical data account for these decrements (IRP Rev F)
Flight Assignment/Project Notes: NOTE: End date change to 12/31/2015 per NSBRI (Ed., 7/7/15)

Task Description: In this project, our objective was to perform structural and functional brain imaging to identify changes in neurocognitive function due to 70 days of head down tilt bed rest. Our central hypotheses were that measures of brain structure, function, and network integrity would change from pre- to post- bed rest to a greater extent than that observed in matched control subjects, but to a lesser extent than what we will observe in crewmembers under our NASA funded flight study NNX11AR02G.

Our Aims were to:

Aim 1- Identify changes in brain structure, function, and network integrity as a function of 60 days head down tilt bed rest and characterize their time course: We acquired brain structural and functional images at two time points pre-, two time points during, and three time points post- bed rest in 18 individuals and 16 controls who were tested at four time points but otherwise went around their daily lives. We hypothesized that bed rest participants would exhibit changes from pre- to post- the intervention that were significantly greater than those seen in control participants across the same time period. Scans conducted during and following bed rest characterized the time course of changes and recovery.

Aim 2- Specify relationships between structural and functional brain changes and performance and characterize their time course: We administered a broad ranging battery of sensory, motor, and cognitive assessments at the time points described for Aim 1. We hypothesized that bed rest participants would exhibit pre- to post-intervention decrements in sensorimotor performance as we have shown in our past work, which we expected would correlate with the neural changes identified under Aim 1. Additionally, for some measures and time points, we expected that there might be no performance effects despite alterations in brain structure and function due to compensatory brain processes, which would be identifiable with neuroimaging approaches. The measures we acquired can be categorized into behavioral assessments and brain imaging assessments. The behavioral tests measured outside of the scanner included: card and cube rotation tests of spatial working memory, digit symbol substitution test of processing speed, rod and frame test of visual bias, pegboard test of bimanual coordination, sensory organization test of vestibular-mediated balance, functional mobility test of obstacle course navigation and vestibular evoked myogenic potential to assess vestibular function.

The neuroimaging tests of brain structure and function included: structural MRI to measure regional brain volumes and relative gray matter density, diffusion weighted scans (often referred to as DTI) to measure structural connectivity integrity, resting state functional MRI to measure functional connectivity integrity, and functional MRI to measure brain networks engaged during the performance of various tasks. The latter tasks included: imaging of the functional vestibular cortex, brain regions engaged during single and dual tasking of cognitive and motor behaviors, brain regions engaged during adaptation of pointing movements to perturbed visual feedback, and brain regions engaged for spatial working memory and foot tapping.

We have nearly completed data analyses and manuscript preparation. We have one paper published, one under second review, and several more that are nearly ready to submit. We found robust changes with bed rest in balance and functional mobility, replicating other studies that have previously reported sensorimotor declines. We also observed changes in brain gray matter volume, functional connectivity, and task based activation that were specific to the time period of the bed rest intervention, many of which were associated with the magnitude of behavioral change. Some metrics exhibited complete recovery by our last time point 12 days post bed rest, while others were trending towards recovery but had not yet returned to baseline levels.

Research Impact/Earth Benefits: While the corpus of research on adaptive plasticity associated with behavioral training has greatly expanded over the past two decades, research on maladaptive plasticity occurring with immobilization is scant. A greater understanding of brain structural and functional changes, and the concomitant behavioral effects, resulting from limb disuse and unloading has implications for rehabilitation of those immobilized by injury, disease, or even simple inactivity. We also have been transferring our new methods for imaging the functional vestibular cortex to the University of Michigan. We will leverage the experience that we attained through development and validation of these methods to conduct some (separately funded) studies related to aging, balance, and vestibular function.

Task Progress & Bibliography Information FY2016 
Task Progress: We are completing our analyses of bed rest induced changes in brain activity during sensorimotor adaptation, spatial working memory, foot movement, and vestibular stimulation tasks. These analyses are nearly complete and we are drafting manuscripts.

Publication in revision: Kopplemans V, Bloomberg JJ, De Dios YE, Wood SJ, Reuter-Lorenz PA, Kofman IS, Riascos R, Mulavara AP, & Seidler R., "Brain plasticity and sensorimotor deterioration as a function of 70 days head down tilt bed rest." [Ed. note August 2017--now published August 2017 in PLoS One; see Bibliography section]

Bibliography Type: Description: (Last Updated: 05/07/2022) 

Show Cumulative Bibliography Listing
 
Articles in Peer-reviewed Journals Koppelmans V, Mulavara AP, Yuan P, Cassady KE, Cooke KA, Wood SJ, Reuter-Lorenz PA, De Dios YE, Stepanyan V, Szecsy DL, Gadd NE, Kofman I, Scott JM, Downs ME, Bloomberg JJ, Ploutz-Snyder L, Seidler RD. "Exercise as potential countermeasure for the effects of 70 days of bed rest on cognitive and sensorimotor performance." Front Syst Neurosci. 2015 Sep 3;9:121. eCollection 2015. http://dx.doi.org/10.3389/fnsys.2015.00121 ; PubMed PMID: 26388746; PubMed Central PMCID: PMC4558429 , Sep-2015
Articles in Peer-reviewed Journals 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 Jun 1;119(6):2145-52. Epub 2018 Feb 28. https://doi.org/10.1152/jn.00693.2017 ; PubMed PMID: 29488843; PubMed Central PMCID: PMC6032127 , Jun-2018
Articles in Peer-reviewed Journals Koppelmans V, Bloomberg JJ, De Dios YE, Wood SJ, Reuter-Lorenz PA, Kofman IS, Riascos R, Mulavara AP, Seidler RD. "Brain plasticity and sensorimotor deterioration as a function of 70 days head down tilt bed rest." PLoS One. 2017 Aug 2;12(8):e0182236. eCollection 2017. https://doi.org/10.1371/journal.pone.0182236 ; PubMed PMID: 28767698; PubMed Central PMCID: PMC5540603 , Aug-2017
Articles in Peer-reviewed Journals 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 Oct 11;13(10):e0205515. https://doi.org/10.1371/journal.pone.0205515 ; PubMed PMID: 30308004; PubMed Central PMCID: PMC6181401 , Oct-2018
Articles in Peer-reviewed Journals 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 (CO2): A pilot study." Front Syst Neurosci. 2020 Jan 10;13:80. https://doi.org/10.3389/fnsys.2019.00080 ; PubMed PMID: 31998084; PubMed Central PMCID: PMC6965349 , Jan-2020
Articles in Peer-reviewed Journals Lee JK, De Dios Y, Kofman I, Mulavara AP, Bloomberg JJ, Seidler RD. "Head down tilt bed rest plus elevated CO2 as a spaceflight analog: Effects on cognitive and sensorimotor performance." Front Hum Neurosci. 2019 Oct 17;13:355. https://doi.org/10.3389/fnhum.2019.00355 ; PubMed PMID: 31680909; PubMed Central PMCID: PMC6811492 , Oct-2019
Articles in Peer-reviewed Journals Noohi F, Kinnaird C, De Dios Y, Kofman I, Wood SJ, Bloomberg JJ, Mulavara AP, Sienko KH, Polk TA, Seidler RD. "Deactivation of somatosensory and visual cortices during vestibular stimulation is associated with older age and poorer balance." PLoS One. 2019 Sep 13;14(9):e0221954. https://doi.org/10.1371/journal.pone.0221954 ; PubMed PMID: 31513630; PubMed Central PMCID: PMC6742389 , Sep-2019
Articles in Peer-reviewed Journals Koppelmans V, Hirsiger S, Mérillat S, Jäncke L, Seidler RD. "Cerebellar gray and white matter volume and their relation with age and manual motor performance in healthy older adults." Hum Brain Mapp. 2015 Jun;36(6):2352-63. Epub 2015 Feb 19. http://dx.doi.org/10.1002/hbm.22775 ; PubMed PMID: 25704867 , Jun-2015
Articles in Peer-reviewed Journals Noohi F, Kinnaird C, De Dios Y, Kofman IS, Wood S, Bloomberg J, Mulavara A, Seidler R. "Functional brain activation in response to a clinical vestibular test correlates with balance." Frontiers in Systems Neuroscience.2017 Mar 10;11:11. eCollection 2017. https://doi.org/10.3389/fnsys.2017.00011 ; PubMed PMID: 28344549; PubMed Central PMCID: PMC5344901 , Mar-2017
Articles in Peer-reviewed Journals 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 Jul 28;14:48. https://doi.org/10.3389/fnsys.2020.00048 ; PMID: 32848641; PMCID: PMC7399639 , Jul-2020
Articles in Peer-reviewed Journals Noohi F, Kinnaird C, De Dios Y, Kofman IS, Wood SJ, Bloomberg J, Mulavara A, Sienko KH, Polk TA, Seidler RD. "Age differences in vestibular brain connectivity are associated with balance performance." Front Aging Neurosci. 2020 Nov 16;12:566331. https://doi.org/10.3389/fnagi.2020.566331 ; PMID: 33312123; PMCID: PMC7703342 , Nov-2020
Articles in Peer-reviewed Journals 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 Mar 30;2(2):tgab022. https://doi.org/10.1093/texcom/tgab022 ; PMID: 34296167; PMCID: PMC8152913 , Mar-2021
Project Title:  Bed Rest as a Spaceflight Analog to Study Neurocognitive Changes: Extent, Longevity, and Neural Bases Reduce
Fiscal Year: FY 2014 
Division: Human Research 
Research Discipline/Element:
HRP BHP:Behavioral Health & Performance (archival in 2017)
Start Date: 08/01/2012  
End Date: 12/31/2015  
Task Last Updated: 09/08/2014 
Download report in PDF pdf
Principal Investigator/Affiliation:   Seidler, Rachael D. Ph.D. / University of Florida 
Address:  Applied Physiology & Kinesiology 
FLG 142, P.O. Box 118205 
Gainesville , FL 32611-8205 
Email: rachaelseidler@ufl.edu 
Phone: 352-294-1722  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Florida 
Joint Agency:  
Comments: NOTE: PI moved to University of Florida in July 2017; previous affiliation was University of Michigan.  
Co-Investigator(s)
Affiliation: 
Mulavara, Ajitkumar  Universities Space Research Association 
Wood, Scott  Azusa Pacific University 
Project Information: Grant/Contract No. NCC 9-58-SA02802 
Responsible Center: NSBRI 
Grant Monitor:  
Center Contact:   
Solicitation / Funding Source: 2011 Crew Health NNJ11ZSA002NA 
Grant/Contract No.: NCC 9-58-SA02802 
Project Type: GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Human Research Program Elements: (1) BHP:Behavioral Health & Performance (archival in 2017)
Human Research Program Risks: (1) Bmed:Risk of Adverse Behavioral Conditions and Psychiatric Disorders
(2) HCI:Risk of Inadequate Human-Computer Interaction
(3) Muscle:Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance
(4) Sensorimotor:Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks (Revised as of IRP Rev M)
Human Research Program Gaps: (1) BMed03:We need to identify and quantify the key threats to and promoters of mission relevant behavioral health and performance during autonomous, long duration and/or long distance exploration missions (IRP Rev F)
(2) SHFE-HCI-03:We need HCI guidelines (e.g., display configuration, screen-navigation) to mitigate the performance decrements identified in SHFE-HCI-08 due to the spaceflight environment (IRP Rev D)
(3) SM26:Determine if exposure to long-duration spaceflight leads to neural structural alterations and if this remodeling impacts cognitive and functional performance (IRP Rev F)
(4) SM7.1:Determine if there are decrements in performance on functional tasks after long-duration spaceflight. Determine how changes in physiological function, exercise activity, and/or clinical data account for these decrements (IRP Rev F)
Flight Assignment/Project Notes: NOTE: End date change to 12/31/2015 per NSBRI (Ed., 7/7/15)

Task Description: In this project, our objective is to perform structural and functional brain imaging to identify changes in neurocognitive function due to 70 days of head down tilt bed rest. Our central hypotheses are that measures of brain structure, function, and network integrity will change from pre to post bed rest to a greater extent than that observed in matched control subjects, but to a lesser extent than what we will observe in crewmembers under our NASA funded flight study NNX11AR02G. Our Aims are to: Aim 1- Identify changes in brain structure, function, and network integrity as a function of 60 days head down tilt bed rest and characterize their time course: We will acquire brain structural and functional images at two time points pre, two time points during, and three time points post bed rest in 13 individuals and 13 age and gender-matched controls. We hypothesize that bed rest participants will exhibit changes from pre to post the intervention that are significantly greater than those seen in control participants across the same time period. Scans conducted during and following bed rest will characterize the time course of changes and recovery. Aim 2- Specify relationships between structural and functional brain changes and performance and characterize their time course: We will administer a broad ranging battery of sensory, motor, and cognitive assessments at the time points described for Aim 1. We hypothesize that bed rest participants will exhibit pre- to post-intervention decrements in sensorimotor performance as we have shown in our past work, which will correlate with the neural changes identified under Aim 1. Additionally, for some measures and time points, we expect that there will be no performance effects despite alterations in brain structure and function due to compensatory brain processes, which will be identifiable with neuroimaging approaches. To date we have fifteen participants enrolled in the bed rest arm of this study; eleven of which have completed all seven of the test sessions. To summarize, the measures we acquire can be categorized into behavioral assessments and brain imaging assessments. The behavioral tests measured outside of the scanner include: card and cube rotation tests of spatial working memory, digit symbol substitution test of processing speed, rod and frame test of visual bias, pegboard test of bimanual coordination, sensory organization test of vestibular-mediated balance, functional mobility test of obstacle course navigation, and vestibular evoked myogenic potential to assess vestibular function. The neuroimaging tests of brain structure and function include: structural MRI to measure regional brain volumes and relative gray matter density, diffusion weighted scans (often referred to as DTI) to measure structural connectivity integrity, resting state functional MRI to measure functional connectivity integrity, and functional MRI to measure brain networks engaged during the performance of various tasks. The latter tasks include: imaging of the functional vestibular cortex, brain regions engaged during single and dual tasking of cognitive and motor behaviors, brain regions engaged during adaptation of pointing movements to perturbed visual feedback, and brain regions engaged for spatial working memory and foot tapping.

We have made significant progress during our second year of support. We continued data collection for our bed rest study and initiated the data collection of 8 normative control subjects, six of whom have completed all four time points. It should be noted that this normative control group will be used for comparison for both our NSBRI funded bed rest study and our NASA funded flight study. During Year 3 we will finish data collection for both the bed rest subjects and normative control subjects and continue analyses of our behavioral and MRI data, with a particular emphasis on addressing whether or how the two types of metrics change together as a function of bed rest. In addition, we will combine the results of the bed rest subjects and the normative control subjects in order to place the results of the bed rest subjects into perspective in terms of effects of bed rest versus potential task learning effects and stability of our protocol.

Research Impact/Earth Benefits: While the corpus of research on adaptive plasticity associated with behavioral training has greatly expanded over the past two decades, research on maladaptive plasticity occurring with immobilization is scant. A greater understanding of brain structural and functional changes, and the concomitant behavioral effects, resulting from limb disuse and unloading has implications for rehabilitation of those immobilized by injury, disease, or even simple inactivity. We also we have been transferring our new methods for imaging the functional vestibular cortex to the University of Michigan. We will leverage the experience that we attained through development and validation of these methods to conduct some (separately funded) studies related to aging, balance, and vestibular function.

Task Progress & Bibliography Information FY2014 
Task Progress: To date, we have fifteen participants enrolled in the bed rest arm of this study; eleven of these have completed all seven of the test sessions. To summarize, the measures we acquire can be categorized into behavioral assessments and brain imaging assessments. The behavioral tests measured outside of the scanner include: card and cube rotation tests of spatial working memory; digit symbol substitution test of processing speed; rod and frame test of visual bias; pegboard test of bimanual coordination; sensory organization test of vestibular-mediated balance; functional mobility test of obstacle course navigation; vestibular evoked myogenic potential to assess vestibular function. The neuroimaging tests of brain structure and function include: structural MRI to measure regional brain volumes and relative gray matter density; diffusion weighted scans (often referred to as DTI) to measure structural connectivity integrity; resting state functional MRI to measure functional connectivity integrity; functional MRI to measure brain networks engaged during the performance of various tasks. The latter tasks include imaging of the functional vestibular cortex; brain regions engaged during single and dual tasking of cognitive and motor behaviors; brain regions engaged during adaptation of pointing movements to perturbed visual feedback; brain regions engaged for spatial working memory, and for foot tapping.

We have made great progress during our second year of support. We initiated the data collection for normative control subjects and have obtained complete data for 6 subjects so far. Also, we added an extra structural MRI measure (i.e., T2-weighted image) to the MRI protocols of our normative and bed rest subjects. T2-weighted imaging is better able in visualizing fluid, and thus could be a more sensitive method to detect fluid redistribution as a result of spaceflight/bed rest that could induce increased intracranial pressure. Our analyses of brain structure have revealed focal and global changes in frontal, temporal, and parietal regions of the brain. Furthermore, we observed increases in third ventricle volume with accumulating time in bed rest.

Bibliography Type: Description: (Last Updated: 05/07/2022) 

Show Cumulative Bibliography Listing
 
Articles in Peer-reviewed Journals Koppelmans V, Erdeniz B, De Dios YE, Wood SJ, Reuter-Lorenz PA, Kofman I, Bloomberg JJ, Mulavara AP, Seidler RD. "Study protocol to examine the effects of spaceflight and a spaceflight analog on neurocognitive performance: extent, longevity, and neural bases." BMC Neurol. 2013 Dec 18;13:205. http://dx.doi.org/10.1186/1471-2377-13-205 ; PubMed PMID: 24350728; PubMed Central PMCID: PMC3878338 , Dec-2013
Project Title:  Bed Rest as a Spaceflight Analog to Study Neurocognitive Changes: Extent, Longevity, and Neural Bases Reduce
Fiscal Year: FY 2013 
Division: Human Research 
Research Discipline/Element:
HRP BHP:Behavioral Health & Performance (archival in 2017)
Start Date: 08/01/2012  
End Date: 07/31/2015  
Task Last Updated: 08/12/2013 
Download report in PDF pdf
Principal Investigator/Affiliation:   Seidler, Rachael D. Ph.D. / University of Florida 
Address:  Applied Physiology & Kinesiology 
FLG 142, P.O. Box 118205 
Gainesville , FL 32611-8205 
Email: rachaelseidler@ufl.edu 
Phone: 352-294-1722  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Florida 
Joint Agency:  
Comments: NOTE: PI moved to University of Florida in July 2017; previous affiliation was University of Michigan.  
Co-Investigator(s)
Affiliation: 
Mulavara, Ajitkumar  Universities Space Research Association 
Wood, Scott  NASA Johnson Space Center 
Project Information: Grant/Contract No. NCC 9-58-SA02802 
Responsible Center: NSBRI 
Grant Monitor:  
Center Contact:   
Solicitation / Funding Source: 2011 Crew Health NNJ11ZSA002NA 
Grant/Contract No.: NCC 9-58-SA02802 
Project Type: GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Human Research Program Elements: (1) BHP:Behavioral Health & Performance (archival in 2017)
Human Research Program Risks: (1) Bmed:Risk of Adverse Behavioral Conditions and Psychiatric Disorders
(2) HCI:Risk of Inadequate Human-Computer Interaction
(3) Muscle:Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance
(4) Sensorimotor:Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks (Revised as of IRP Rev M)
Human Research Program Gaps: (1) BMed03:We need to identify and quantify the key threats to and promoters of mission relevant behavioral health and performance during autonomous, long duration and/or long distance exploration missions (IRP Rev F)
(2) SHFE-HCI-03:We need HCI guidelines (e.g., display configuration, screen-navigation) to mitigate the performance decrements identified in SHFE-HCI-08 due to the spaceflight environment (IRP Rev D)
(3) SM26:Determine if exposure to long-duration spaceflight leads to neural structural alterations and if this remodeling impacts cognitive and functional performance (IRP Rev F)
(4) SM7.1:Determine if there are decrements in performance on functional tasks after long-duration spaceflight. Determine how changes in physiological function, exercise activity, and/or clinical data account for these decrements (IRP Rev F)
Task Description: In this project, our objective is to perform structural and functional brain imaging to identify changes in neurocognitive function due to 70 days of head down tilt bed rest. Our central hypotheses are that measures of brain structure, function, and network integrity will change from pre to post bed rest to a greater extent than that observed in matched control subjects, but to a lesser extent than what we will observe in crewmembers under our NASA funded flight study NNX11AR02G. Our Aims are to: Aim 1- Identify changes in brain structure, function, and network integrity as a function of 60 days head down tilt bed rest and characterize their time course: We will acquire brain structural and functional images at two time points pre, two time points during, and three time points post bed rest in 13 individuals and 13 age and gender-matched controls. We hypothesize that bed rest participants will exhibit changes from pre to post the intervention that are significantly greater than those seen in control participants across the same time period. Scans conducted during and following bed rest will characterize the time course of changes and recovery. Aim 2- Specify relationships between structural and functional brain changes and performance and characterize their time course: We will administer a broad ranging battery of sensory, motor, and cognitive assessments at the time points described for Aim 1. We hypothesize that bed rest participants will exhibit pre- to post-intervention decrements in sensorimotor performance as we have shown in our past work, which will correlate with the neural changes identified under Aim 1. Additionally, for some measures and time points, we expect that there will be no performance effects despite alterations in brain structure and function due to compensatory brain processes that will be identifiable with neuroimaging approaches. To date we have five participants enrolled in the bed rest arm of this study; three of these have completed all seven of the test sessions. To summarize, the measures we acquire can be categorized into behavioral assessments and brain imaging assessments. The behavioral tests measured outside of the scanner include: card and cube rotation tests of spatial working memory; digit symbol substitution test of processing speed; rod and frame test of visual bias; pegboard test of bimanual coordination; sensory organization test of vestibular-mediated balance; functional mobility test of obstacle course navigation; vestibular evoked myogenic potential to assess vestibular function. The neuroimaging tests of brain structure and function include: structural MRI to measure regional brain volumes and relative gray matter density; diffusion weighted scans (often referred to as DTI) to measure structural connectivity integrity; resting state functional MRI to measure functional connectivity integrity; functional MRI to measure brain networks engaged during the performance of various tasks. The latter tasks include imaging of the functional vestibular cortex; brain regions engaged during single and dual tasking of cognitive and motor behaviors; brain regions engaged during adaptation of pointing movements to perturbed visual feedback; brain regions engaged for spatial working memory, and for foot tapping.

We have made great progress during our first year of support. Our stand alone protocol received IRB approval from the University of Michigan and NASA and was then wrapped into the bed rest Flight Analog Project UTMB IRB protocol. We invested an extensive amount of time and effort into assembling, integrating, and troubleshooting our hardware and software with the bed rest facility resources. This included developing and setting up unique hardware and software to enable functional MRI testing at UTMB Galveston, which previously had only acquired structural and clinical MRI scans. We also ran numerous pilot tests to ensure that we could collect our data within the time allotted and to verify that we were getting clean and reliable metrics. We have made one methodological change as a result of our pilot testing. We initially were stimulating the functional vestibular cortex via auditory clicks of a particular sound decibel. This moves fluid in the inner ear, stimulating vestibular receptor hair cells. The clicks, although within the OSHA safety standards, are quite loud and difficult for some subjects to tolerate. Moreover, the brain activity associated with this mode of stimulation was rather variable across test sessions for the initial subjects. As a result, we have extensively piloted and are now implementing vestibular stimulation with a head tapper device. This pneumatically driven device taps the head at a very low force level. The resulting vibration is transmitted via bone conduction to the vestibular system. Thus far, the brain activation patterns associated with this mode of stimulation appear to have better reliability. Over the next year we will acquire data from additional subjects and continue analyses of our behavioral and MRI data, with a particular emphasis on addressing whether / how the two types of metrics change together as a function of bed rest. Moreover, we will soon be launching our longitudinal control study.

Research Impact/Earth Benefits: While the corpus of research on adaptive plasticity associated with behavioral training has greatly expanded over the past two decades, research on maladaptive plasticity occurring with immobilization is scant. A greater understanding of brain structural and functional changes, and the concomitant behavioral effects, resulting from limb disuse and unloading has implications for rehabilitation of those immobilized by injury, disease, or even simple inactivity. In addition, we have been working with Engineering Acoustics Incorporated to have them modify a device that they manufacture for vestibular testing to render it MRI compatible. There are few methods available for stimulating the vestibular cortex that are amenable to functional imaging. For example, one approach involves caloric stimulation via delivery of cool water to the inner ear. This is messy to work with in the MRI environment and can also be quite painful for subjects. We initially developed a system capable of delivering precisely calibrated sound to the inner ear which also results in vestibular stimulation. This is somewhat painful for participants as well. The route that we decided to go with involves applying a very low force tap to the head. Vibration is transmitted via bone conduction to the vestibular system, resulting in depolarization of the hair cell receptors. The ease of this approach is increasing its clinical popularity, and numerous experimental and modeling studies have been conducted recently to verify how the signal is transmitted in the vestibular system. We are the first group to evaluate this method in the functional MRI environment. We are gearing up to conduct a validation study of this type of stimulation at the University of Michigan as an offshoot of our NSBRI project. Being able to image the functional vestibular cortex in human subjects will be important for better understanding of deficits faced by vestibular patients. Moreover, it can be used as a neural marker of balance training effects. We are excited to further develop this line of work.

Task Progress & Bibliography Information FY2013 
Task Progress: To date we have five participants enrolled in the bed rest arm of this study; three of these have completed all seven of the test sessions. To summarize, the measures we acquire can be categorized into behavioral assessments and brain imaging assessments. The behavioral tests measured outside of the scanner include: card and cube rotation tests of spatial working memory; digit symbol substitution test of processing speed; rod and frame test of visual bias; pegboard test of bimanual coordination; sensory organization test of vestibular-mediated balance; functional mobility test of obstacle course navigation; vestibular evoked myogenic potential to assess vestibular function. The neuroimaging tests of brain structure and function include: structural MRI to measure regional brain volumes and relative gray matter density; diffusion weighted scans (often referred to as DTI) to measure structural connectivity integrity; resting state functional MRI to measure functional connectivity integrity; functional MRI to measure brain networks engaged during the performance of various tasks. The latter tasks include imaging of the functional vestibular cortex; brain regions engaged during single and dual tasking of cognitive and motor behaviors; brain regions engaged during adaptation of pointing movements to perturbed visual feedback; brain regions engaged for spatial working memory, and for foot tapping.

We have made great progress during our first year of support. Our stand alone protocol received IRB approval from the University of Michigan and NASA and was then wrapped into the bed rest Flight Analog Project UTMB IRB protocol. We invested an extensive amount of time and effort into assembling, integrating, and troubleshooting our hardware and software with the bed rest facility resources. This included developing and setting up unique hardware and software to enable functional MRI testing at UTMB Galveston, which previously had only acquired structural and clinical MRI scans. We also ran numerous pilot tests to ensure that we could collect our data within the time allotted and to verify that we were getting clean and reliable metrics. We have streamlined our analytical approaches to include assessments of test retest reliability across the first two pre test time points as well as repeated measures approaches for evaluating the impact of bed rest. Thus far we have observed high intraclass correlations for our pre test metrics across five participants tested, and robust changes in behavioral and brain functional metrics with bed rest (n = 3 completed). Our analyses of brain structure have not yielded any effects of bed rest; however, data from only two participants have been analyzed thus far, and we also had some challenges with acquiring MRI data using consistent parameters. This issue has been resolved for testing moving forward.

Bibliography Type: Description: (Last Updated: 05/07/2022) 

Show Cumulative Bibliography Listing
 
 None in FY 2013
Project Title:  Bed Rest as a Spaceflight Analog to Study Neurocognitive Changes: Extent, Longevity, and Neural Bases Reduce
Fiscal Year: FY 2012 
Division: Human Research 
Research Discipline/Element:
HRP BHP:Behavioral Health & Performance (archival in 2017)
Start Date: 08/01/2012  
End Date: 07/31/2015  
Task Last Updated: 10/23/2012 
Download report in PDF pdf
Principal Investigator/Affiliation:   Seidler, Rachael D. Ph.D. / University of Florida 
Address:  Applied Physiology & Kinesiology 
FLG 142, P.O. Box 118205 
Gainesville , FL 32611-8205 
Email: rachaelseidler@ufl.edu 
Phone: 352-294-1722  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: University of Florida 
Joint Agency:  
Comments: NOTE: PI moved to University of Florida in July 2017; previous affiliation was University of Michigan.  
Co-Investigator(s)
Affiliation: 
Mulavara, Ajitkumar  Universities Space Research Association 
Wood, Scott  NASA Johnson Space Center 
Project Information: Grant/Contract No. NCC 9-58-SA02802 
Responsible Center: NSBRI 
Grant Monitor:  
Center Contact:   
Solicitation / Funding Source: 2011 Crew Health NNJ11ZSA002NA 
Grant/Contract No.: NCC 9-58-SA02802 
Project Type: GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:  
No. of PhD Candidates:  
No. of Master's Candidates:  
No. of Bachelor's Candidates:  
No. of PhD Degrees:  
No. of Master's Degrees:  
No. of Bachelor's Degrees:  
Human Research Program Elements: (1) BHP:Behavioral Health & Performance (archival in 2017)
Human Research Program Risks: (1) Bmed:Risk of Adverse Behavioral Conditions and Psychiatric Disorders
(2) HCI:Risk of Inadequate Human-Computer Interaction
(3) Muscle:Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance
(4) Sensorimotor:Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks (Revised as of IRP Rev M)
Human Research Program Gaps: (1) BMed03:We need to identify and quantify the key threats to and promoters of mission relevant behavioral health and performance during autonomous, long duration and/or long distance exploration missions (IRP Rev F)
(2) SHFE-HCI-03:We need HCI guidelines (e.g., display configuration, screen-navigation) to mitigate the performance decrements identified in SHFE-HCI-08 due to the spaceflight environment (IRP Rev D)
(3) SM26:Determine if exposure to long-duration spaceflight leads to neural structural alterations and if this remodeling impacts cognitive and functional performance (IRP Rev F)
(4) SM7.1:Determine if there are decrements in performance on functional tasks after long-duration spaceflight. Determine how changes in physiological function, exercise activity, and/or clinical data account for these decrements (IRP Rev F)
Task Description: NRA NNJ11ZSA002NA requests NSBRI proposals to “Determine the effects of an analog of long-duration spaceflight on neural structural alterations and assess associated impacts on cognitive and behavioral performance”. In response to this call, we propose to perform structural and functional MR brain imaging to identify the relationship between changes in participants’ neurocognitive function and neural structural alterations following 60 days of head-down tilt bed rest. Our central hypotheses are that measures of brain structure, function, and network integrity will change from pre to post bed rest to a greater extent than in control participants over the same time period (Aim 1). Moreover, we predict that these changes will correlate with indices of cognitive, sensory, and motor function in a structurally selective fashion (Aim 2). This work complements our ongoing NASA funded project NNX11AR02G “Spaceflight Effects on Neurocognitive Performance: Extent, Longevity, and Neural Bases”. With the current proposal, we will be able to determine the neural and neurocognitive effects of unloading, reduced sensory inputs, and increased cephalic fluid distribution. This will enable us to parse out the multiple mechanisms contributing to any spaceflight induced neural structural and behavioral changes that we observe in our ongoing project. Our interdisciplinary approach utilizes cutting edge neuroimaging techniques and a broad battery of sensory, motor, and cognitive assessments to investigate neuroplastic and maladaptive brain changes following long duration bed rest. Success in this endeavor would 1) aid in identification of the underlying neural mechanisms and operational risks of spaceflight-induced changes in behavior using a well established spaceflight analog, and 2) identify whether a return to normative behavioral function following recovery from prolonged bed rest is associated with a restitution of brain structure and function or instead is supported by substitution with compensatory brain processes.

Research Impact/Earth Benefits: 0

Task Progress & Bibliography Information FY2012 
Task Progress: New project for FY2012.

Bibliography Type: Description: (Last Updated: 05/07/2022) 

Show Cumulative Bibliography Listing
 
 None in FY 2012