1
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Clément G, Macaulay TR, Bollinger A, Weiss H, Wood SJ. Functional activities essential for space exploration performed in partial gravity during parabolic flight. NPJ Microgravity 2024; 10:86. [PMID: 39152140 PMCID: PMC11329648 DOI: 10.1038/s41526-024-00422-3] [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: 04/06/2024] [Accepted: 07/28/2024] [Indexed: 08/19/2024] Open
Abstract
Test subjects were assessed in a partial gravity environment during parabolic flight while they performed mission-critical activities that challenged their balance and locomotion. These functional activities included rising from a seated position and walking, jumping down, recovering from falls, and maintaining an upright stance. Twelve volunteers were tested during 10 parabolas that produced 0.25×g, 0.5×g, or 0.75×g, and at 1×g during level flight intervals between parabolas. Additionally, 14 other subjects were tested using identical procedures in a 1×g laboratory setting. Partial gravity altered the performance of settling after standing and navigating around obstacles. As gravity levels decreased, the time required to stand up, settle, walk, and negotiate obstacles, and the number of falls increased. Information obtained from these tests will allow space agencies to assess the vestibular, sensorimotor, and cardiovascular risks associated with different levels of partial gravity.
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Affiliation(s)
| | | | | | - Hannah Weiss
- KBR, 2400 E NASA Parkway, Houston, TX, 77058, USA
| | - Scott J Wood
- Neuroscience Laboratory, NASA Johnson Space Center, 2200 E NASA Parkway, Houston, TX, 77058, USA
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2
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Cherif M, Brose U, Hirt MR, Ryser R, Silve V, Albert G, Arnott R, Berti E, Cirtwill A, Dyer A, Gauzens B, Gupta A, Ho HC, Portalier SMJ, Wain D, Wootton K. The environment to the rescue: can physics help predict predator-prey interactions? Biol Rev Camb Philos Soc 2024. [PMID: 38855988 DOI: 10.1111/brv.13105] [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: 06/30/2023] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024]
Abstract
Understanding the factors that determine the occurrence and strength of ecological interactions under specific abiotic and biotic conditions is fundamental since many aspects of ecological community stability and ecosystem functioning depend on patterns of interactions among species. Current approaches to mapping food webs are mostly based on traits, expert knowledge, experiments, and/or statistical inference. However, they do not offer clear mechanisms explaining how trophic interactions are affected by the interplay between organism characteristics and aspects of the physical environment, such as temperature, light intensity or viscosity. Hence, they cannot yet predict accurately how local food webs will respond to anthropogenic pressures, notably to climate change and species invasions. Herein, we propose a framework that synthesises recent developments in food-web theory, integrating body size and metabolism with the physical properties of ecosystems. We advocate for combination of the movement paradigm with a modular definition of the predation sequence, because movement is central to predator-prey interactions, and a generic, modular model is needed to describe all the possible variation in predator-prey interactions. Pending sufficient empirical and theoretical knowledge, our framework will help predict the food-web impacts of well-studied physical factors, such as temperature and oxygen availability, as well as less commonly considered variables such as wind, turbidity or electrical conductivity. An improved predictive capability will facilitate a better understanding of ecosystem responses to a changing world.
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Affiliation(s)
- Mehdi Cherif
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Ulrich Brose
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Myriam R Hirt
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Remo Ryser
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Violette Silve
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Georg Albert
- Department of Forest Nature Conservation, Georg-August-Universität, Büsgenweg 3, Göttingen, 37077, Germany
| | - Russell Arnott
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, Cambridgeshire, CB2 1LR, UK
| | - Emilio Berti
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Alyssa Cirtwill
- Spatial Foodweb Ecology Group, Research Centre for Ecological Change (REC), Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 4 (Yliopistonkatu 3), Helsinki, 00014, Finland
| | - Alexander Dyer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Benoit Gauzens
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Anhubav Gupta
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zürich, 8057, Switzerland
| | - Hsi-Cheng Ho
- Institute of Ecology and Evolutionary Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 106, Taiwan
| | - Sébastien M J Portalier
- Department of Mathematics and Statistics, University of Ottawa, STEM Complex, room 342, 150 Louis-Pasteur Pvt, Ottawa, Ontario, K1N 6N5, Canada
| | - Danielle Wain
- 7 Lakes Alliance, Belgrade Lakes, 137 Main St, Belgrade Lakes, ME, 04918, USA
| | - Kate Wootton
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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3
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Wang Y, Neto OP, Weinrich M, Abbott R, Diaz-Artiles A, Kennedy DM. The effect of inherent and incidental constraints on bimanual force control in simulated Martian gravity. Hum Mov Sci 2024; 95:103199. [PMID: 38518737 DOI: 10.1016/j.humov.2024.103199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 03/24/2024]
Abstract
The ability to coordinate actions between the limbs is important for many operationally relevant tasks associated with space exploration. A future milestone in space exploration is sending humans to Mars. Therefore, an experiment was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with the bimanual control of force in simulated Martian gravity. A head-up tilt (HUT)/head-down tilt (HDT) paradigm was used to simulate gravity on Mars (22.3° HUT). Right limb dominant participants (N = 11) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multifrequency patterns by exerting force with their right and left limbs. Lissajous displays were provided to guide task performance. Participants performed 14 twenty-second practice trials at 90° HUT (Earth). Following a 30-min rest period, participants performed 2 test trials for each coordination pattern in both Earth and Mars conditions. Performance during the test trials were compared. Results indicated very effective temporal performance of the goal coordination tasks in both gravity conditions. However, results indicated differences associated with the production of force between Earth and Mars. In general, participants produced less force in simulated Martian gravity than in the Earth condition. In addition, force production was more harmonic in Martian gravity than Earth gravity for both limbs, indicating that less force distortions (adjustments, hesitations, and/or perturbations) occurred in the Mars condition than in the Earth condition. The force coherence analysis indicated significantly higher coherence in the 1:1 task than in the 1:2 task for all force frequency bands, with the highest level of coherence in the 1-4 Hz frequency band for both gravity conditions. High coherence in the 1-4 Hz frequency band is associated with a common neural drive that activates the two arms simultaneously and is consistent with the requirements of the two tasks. The results also support the notion that neural crosstalk stabilizes the performance of the 1:1 in-phase task. In addition, significantly higher coherence in the 8-12 Hz frequency bands were observed for the Earth condition than the Mars condition. Force coherence in the 8-12 Hz bands is associated with the processing of sensorimotor information, suggesting that participants were better at integrating visual, proprioceptive, and/or tactile feedback in Earth than for the Mars condition. Overall, the results indicate less neural interference in Martian gravity; however, participants appear to be more effective at using the Lissajous displays to guide performance under Earth's gravity.
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Affiliation(s)
- Yiyu Wang
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA
| | - Osmar P Neto
- Department of Biomedical Engineering, Anhembi Morumbi University, SP, Brazil
| | - Madison Weinrich
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA
| | - Renee Abbott
- Department of Aerospace Engineering, Texas A&M University, TX, USA
| | - Ana Diaz-Artiles
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA; Department of Aerospace Engineering, Texas A&M University, TX, USA
| | - Deanna M Kennedy
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA.
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4
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Allred AR, Clark TK. A computational model of motion sickness dynamics during passive self-motion in the dark. Exp Brain Res 2024; 242:1127-1148. [PMID: 38489025 DOI: 10.1007/s00221-024-06804-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/08/2024] [Indexed: 03/17/2024]
Abstract
Predicting the time course of motion sickness symptoms enables the evaluation of provocative stimuli and the development of countermeasures for reducing symptom severity. In pursuit of this goal, we present an Observer-driven model of motion sickness for passive motions in the dark. Constructed in two stages, this model predicts motion sickness symptoms by bridging sensory conflict (i.e., differences between actual and expected sensory signals) arising from the Observer model of spatial orientation perception (stage 1) to Oman's model of motion sickness symptom dynamics (stage 2; presented in 1982 and 1990) through a proposed "Normalized Innovation Squared" statistic. The model outputs the expected temporal development of human motion sickness symptom magnitudes (mapped to the Misery Scale) at a population level, due to arbitrary, 6-degree-of-freedom, self-motion stimuli. We trained model parameters using individual subject responses collected during fore-aft translations and off-vertical axis of rotation motions. Improving on prior efforts, we only used datasets with experimental conditions congruent with the perceptual stage (i.e., adequately provided passive motions without visual cues) to inform the model. We assessed model performance by predicting an unseen validation dataset, producing a Q2 value of 0.91. Demonstrating this model's broad applicability, we formulate predictions for a host of stimuli, including translations, earth-vertical rotations, and altered gravity, and we provide our implementation for other users. Finally, to guide future research efforts, we suggest how to rigorously advance this model (e.g., incorporating visual cues, active motion, responses to motion of different frequency, etc.).
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Affiliation(s)
- Aaron R Allred
- Smead Department of Aerospace Engineering Sciences, University of Colorado-Boulder, Boulder, CO, USA.
| | - Torin K Clark
- Smead Department of Aerospace Engineering Sciences, University of Colorado-Boulder, Boulder, CO, USA
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5
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Allred AR, Kravets VG, Ahmed N, Clark TK. Modeling orientation perception adaptation to altered gravity environments with memory of past sensorimotor states. Front Neural Circuits 2023; 17:1190582. [PMID: 37547052 PMCID: PMC10399228 DOI: 10.3389/fncir.2023.1190582] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 06/29/2023] [Indexed: 08/08/2023] Open
Abstract
Transitioning between gravitational environments results in a central reinterpretation of sensory information, producing an adapted sensorimotor state suitable for motor actions and perceptions in the new environment. Critically, this central adaptation is not instantaneous, and complete adaptation may require weeks of prolonged exposure to novel environments. To mitigate risks associated with the lagging time course of adaptation (e.g., spatial orientation misperceptions, alterations in locomotor and postural control, and motion sickness), it is critical that we better understand sensorimotor states during adaptation. Recently, efforts have emerged to model human perception of orientation and self-motion during sensorimotor adaptation to new gravity stimuli. While these nascent computational frameworks are well suited for modeling exposure to novel gravitational stimuli, they have yet to distinguish how the central nervous system (CNS) reinterprets sensory information from familiar environmental stimuli (i.e., readaptation). Here, we present a theoretical framework and resulting computational model of vestibular adaptation to gravity transitions which captures the role of implicit memory. This advancement enables faster readaptation to familiar gravitational stimuli, which has been observed in repeat flyers, by considering vestibular signals dependent on the new gravity environment, through Bayesian inference. The evolution and weighting of hypotheses considered by the CNS is modeled via a Rao-Blackwellized particle filter algorithm. Sensorimotor adaptation learning is facilitated by retaining a memory of past harmonious states, represented by a conditional state transition probability density function, which allows the model to consider previously experienced gravity levels (while also dynamically learning new states) when formulating new alternative hypotheses of gravity. In order to demonstrate our theoretical framework and motivate future experiments, we perform a variety of simulations. These simulations demonstrate the effectiveness of this model and its potential to advance our understanding of transitory states during which central reinterpretation occurs, ultimately mitigating the risks associated with the lagging time course of adaptation to gravitational environments.
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Affiliation(s)
- Aaron R. Allred
- Bioastronautics Laboratory, Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Victoria G. Kravets
- Bioastronautics Laboratory, Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Nisar Ahmed
- Cooperative Human-Robot Interaction Laboratory, Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Torin K. Clark
- Bioastronautics Laboratory, Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
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6
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Gonzalez RA, Siderskiy V, Breen P, Serrador JM, Kapila V. Transcranial Doppler Remote Positioning System with Virtual Reality Integration for Vestibular Studies. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083229 DOI: 10.1109/embc40787.2023.10340606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Transcranial doppler (TCD) ultrasound probes are an invaluable tool in cerebral blood flow (CBF) studies. Their operation demands maintaining consistent pose on the subject throughout the experimental protocol. However, the displacement of the TCD probe during vestibular studies is common and substantially prolongs the experiment or even terminates it. This is a significant challenge for integrating motion-based vestibular studies with CBF investigations. In response, a mechatronics system is designed to allow remote repositioning of the TCD probe during data collection experiments while the subject is wearing a head mounted virtual reality (VR) display and seated in a vestibular disorientation device. This paper presents the design, prototype, and operation of this mechatronics apparatus.Clinical Relevance- The mechatronics apparatus of this paper can enable motion-based vestibular studies that entail the use of CBF velocity measurement and head-mounted virtual reality display.
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7
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Teaford M, Keller K, Merfeld DM. The contribution of interoceptive signals to spatial orientation: A mini-review. Neurosci Biobehav Rev 2022; 143:104943. [DOI: 10.1016/j.neubiorev.2022.104943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/15/2022] [Accepted: 10/31/2022] [Indexed: 11/07/2022]
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8
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Kravets VG, Dixon JB, Ahmed NR, Clark TK. COMPASS: Computations for Orientation and Motion Perception in Altered Sensorimotor States. Front Neural Circuits 2021; 15:757817. [PMID: 34720889 PMCID: PMC8553968 DOI: 10.3389/fncir.2021.757817] [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: 08/12/2021] [Accepted: 09/23/2021] [Indexed: 11/30/2022] Open
Abstract
Reliable perception of self-motion and orientation requires the central nervous system (CNS) to adapt to changing environments, stimuli, and sensory organ function. The proposed computations required of neural systems for this adaptation process remain conceptual, limiting our understanding and ability to quantitatively predict adaptation and mitigate any resulting impairment prior to completing adaptation. Here, we have implemented a computational model of the internal calculations involved in the orientation perception system’s adaptation to changes in the magnitude of gravity. In summary, we propose that the CNS considers parallel, alternative hypotheses of the parameter of interest (in this case, the CNS’s internal estimate of the magnitude of gravity) and uses the associated sensory conflict signals (i.e., difference between sensory measurements and the expectation of them) to sequentially update the posterior probability of each hypothesis using Bayes rule. Over time, an updated central estimate of the internal magnitude of gravity emerges from the posterior probability distribution, which is then used to process sensory information and produce perceptions of self-motion and orientation. We have implemented these hypotheses in a computational model and performed various simulations to demonstrate quantitative model predictions of adaptation of the orientation perception system to changes in the magnitude of gravity, similar to those experienced by astronauts during space exploration missions. These model predictions serve as quantitative hypotheses to inspire future experimental assessments.
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Affiliation(s)
- Victoria G Kravets
- Bioastronautics Laboratory, Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Jordan B Dixon
- Bioastronautics Laboratory, Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Nisar R Ahmed
- COHRINT Laboratory, Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
| | - Torin K Clark
- Bioastronautics Laboratory, Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, United States
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9
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Spatial orientation: Model-based approach to multi-sensory mechanisms. PROGRESS IN BRAIN RESEARCH 2019. [PMID: 31239133 DOI: 10.1016/bs.pbr.2019.04.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Perception of spatial orientation is generated through multimodal sensory integration. In this process, there are systematic errors with changes in the head or body position, which reflect challenges for the brain in maintaining a common sensory reference frame for spatial orientation. Here, we focus on this multisensory aspect of spatial orientation. We review a Bayesian spatial perception model that can be used as a framework to study sensory contributions to spatial orientation during lateral head tilts and probe neural networks involved in this process.
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10
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Clark TK, Newman MC, Karmali F, Oman CM, Merfeld DM. Mathematical models for dynamic, multisensory spatial orientation perception. PROGRESS IN BRAIN RESEARCH 2019; 248:65-90. [PMID: 31239146 DOI: 10.1016/bs.pbr.2019.04.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mathematical models have been proposed for how the brain interprets sensory information to produce estimates of self-orientation and self-motion. This process, spatial orientation perception, requires dynamically integrating multiple sensory modalities, including visual, vestibular, and somatosensory cues. Here, we review the progress in mathematical modeling of spatial orientation perception, focusing on dynamic multisensory models, and the experimental paradigms in which they have been validated. These models are primarily "black box" or "as if" models for how the brain processes spatial orientation cues. Yet, they have been effective scientifically, in making quantitative hypotheses that can be empirically assessed, and operationally, in investigating aircraft pilot disorientation, for example. The primary family of models considered, the observer model, implements estimation theory approaches, hypothesizing that internal models (i.e., neural systems replicating the behavior/dynamics of physical systems) are used to produce expected sensory measurements. Expected signals are then compared to actual sensory afference, yielding sensory conflict, which is weighted to drive central perceptions of gravity, angular velocity, and translation. This approach effectively predicts a wide range of experimental scenarios using a small set of fixed free parameters. We conclude with limitations and applications of existing mathematical models and important areas of future work.
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Affiliation(s)
- Torin K Clark
- Smead Aerospace Engineering Sciences, University of Colorado-Boulder, Boulder, CO, United States.
| | - Michael C Newman
- Environmental Tectonics Corporation, Southampton, PA, United States
| | - Faisal Karmali
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States; Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - Charles M Oman
- Human Systems Laboratory, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Daniel M Merfeld
- Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, United States; Naval Aerospace Medical Research Lab (NAMRL), Naval Medical Research Unit-Dayton (NAMRUD), Dayton, OH, United States
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11
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Clément G, Reschke MF, Wood SJ. Vibrotactile Feedback Improves Manual Control of Tilt After Spaceflight. Front Physiol 2018; 9:1850. [PMID: 30618848 PMCID: PMC6305736 DOI: 10.3389/fphys.2018.01850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/07/2018] [Indexed: 11/13/2022] Open
Abstract
The objectives of this study were to quantify decrements in controlling tilt on astronauts immediately after short-duration spaceflight, and to evaluate vibrotactile feedback of tilt as a potential countermeasure. Eleven subjects were rotated on a variable radius centrifuge (216°/s <20 cm radius) in a darkened room to elicit tilt disturbance in roll (≤± 15°). Nine of these subjects performed a nulling task in the pitch plane (≤±7.5°). Small tactors placed around the torso vibrated at 250 Hz to provide tactile feedback when the body tilt exceeded predetermined levels. The subjects performed closed-loop nulling tasks during random tilt steps with and without this vibrotactile feedback of tilt. There was a significant effect of spaceflight on the performance of the nulling tasks based on root mean square error. Performance returned to baseline levels 1-2 days after landing. Vibrotactile feedback significantly improved performance of nulling tilt during all test sessions. Nulling performance in roll was significantly correlated with performance in pitch. These results indicate that adaptive changes in astronauts' vestibular processing during spaceflight impair their ability to manually control tilt following transitions between gravitational environments. A simple vibrotactile prosthesis improves their ability to null-out tilt within a limited range of motion disturbances.
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Affiliation(s)
- Gilles Clément
- Lyon Neuroscience Research Center, Bron, France.,KBRwyle, Houston, TX, United States
| | - Millard F Reschke
- Neuroscience Laboratories, National Aeronautics and Space Administration Johnson Space Center, Houston, TX, United States
| | - Scott J Wood
- Neuroscience Laboratories, National Aeronautics and Space Administration Johnson Space Center, Houston, TX, United States.,Azusa Pacific University, Azusa, CA, United States
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12
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Galvan-Garza RC, Clark TK, Sherwood D, Diaz-Artiles A, Rosenberg M, Natapoff A, Karmali F, Oman CM, Young LR. Human perception of whole body roll-tilt orientation in a hypogravity analog: underestimation and adaptation. J Neurophysiol 2018; 120:3110-3121. [PMID: 30332330 DOI: 10.1152/jn.00140.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Overestimation of roll tilt in hypergravity ("G-excess" illusion) has been demonstrated, but corresponding sustained hypogravic conditions are impossible to create in ground laboratories. In this article we describe the first systematic experimental evidence that in a hypogravity analog, humans underestimate roll tilt. We studied perception of self-roll tilt in nine subjects, who were supine while spun on a centrifuge to create a hypogravity analog. By varying the centrifuge rotation rate, we modulated the centripetal acceleration (GC) at the subject's head location (0.5 or 1 GC) along the body axis. We measured orientation perception using a subjective visual vertical task in which subjects aligned an illuminated bar with their perceived centripetal acceleration direction during tilts (±11.5-28.5°). As hypothesized, based on the reduced utricular otolith shearing, subjects initially underestimated roll tilts in the 0.5 GC condition compared with the 1 GC condition (mean perceptual gain change = -0.27, P = 0.01). When visual feedback was given after each trial in 0.5 GC, subjects' perceptual gain increased in approximately exponential fashion over time (time constant = 16 tilts or 13 min), and after 45 min, the perceptual gain was not significantly different from the 1 GC baseline (mean gain difference between 1 GC initial and 0.5 GC final = 0.16, P = 0.3). Thus humans modified their interpretation of sensory cues to more correctly report orientation during this hypogravity analog. Quantifying the acute orientation perceptual learning in such an altered gravity environment may have implications for human space exploration on the moon or Mars. NEW & NOTEWORTHY Humans systematically overestimate roll tilt in hypergravity. However, human perception of orientation in hypogravity has not been quantified across a range of tilt angles. Using a centrifuge to create a hypogravity centripetal acceleration environment, we found initial underestimation of roll tilt. Providing static visual feedback, perceptual learning reduced underestimation during the hypogravity analog. These altered gravity orientation perceptual errors and adaptation may have implications for astronauts.
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Affiliation(s)
- Raquel C Galvan-Garza
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Torin K Clark
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Otology and Laryngology, Harvard Medical School , Boston, Massachusetts.,Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts.,Smead Aerospace Engineering Sciences, University of Colorado , Boulder, Colorado
| | - David Sherwood
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Ana Diaz-Artiles
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts.,Sibley School of Mechanical and Aerospace Engineering, Cornell University , Ithaca, New York.,Aerospace Engineering, Texas A&M University , College Station, Texas
| | - Marissa Rosenberg
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,KBRwyle Science, Technology, and Engineering Group , Houston, Texas
| | - Alan Natapoff
- Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Faisal Karmali
- Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Otology and Laryngology, Harvard Medical School , Boston, Massachusetts.,Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Charles M Oman
- Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Laurence R Young
- Man-Vehicle Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts
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13
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Rosenberg MJ, Galvan-Garza RC, Clark TK, Sherwood DP, Young LR, Karmali F. Human manual control precision depends on vestibular sensory precision and gravitational magnitude. J Neurophysiol 2018; 120:3187-3197. [PMID: 30379610 DOI: 10.1152/jn.00565.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Precise motion control is critical to human survival on Earth and in space. Motion sensation is inherently imprecise, and the functional implications of this imprecision are not well understood. We studied a "vestibular" manual control task in which subjects attempted to keep themselves upright with a rotational hand controller (i.e., joystick) to null out pseudorandom, roll-tilt motion disturbances of their chair in the dark. Our first objective was to study the relationship between intersubject differences in manual control performance and sensory precision, determined by measuring vestibular perceptual thresholds. Our second objective was to examine the influence of altered gravity on manual control performance. Subjects performed the manual control task while supine during short-radius centrifugation, with roll tilts occurring relative to centripetal accelerations of 0.5, 1.0, and 1.33 GC (1 GC = 9.81 m/s2). Roll-tilt vestibular precision was quantified with roll-tilt vestibular direction-recognition perceptual thresholds, the minimum movement that one can reliably distinguish as leftward vs. rightward. A significant intersubject correlation was found between manual control performance (defined as the standard deviation of chair tilt) and thresholds, consistent with sensory imprecision negatively affecting functional precision. Furthermore, compared with 1.0 GC manual control was more precise in 1.33 GC (-18.3%, P = 0.005) and less precise in 0.5 GC (+39.6%, P < 0.001). The decrement in manual control performance observed in 0.5 GC and in subjects with high thresholds suggests potential risk factors for piloting and locomotion, both on Earth and during human exploration missions to the moon (0.16 G) and Mars (0.38 G). NEW & NOTEWORTHY The functional implications of imprecise motion sensation are not well understood. We found a significant correlation between subjects' vestibular perceptual thresholds and performance in a manual control task (using a joystick to keep their chair upright), consistent with sensory imprecision negatively affecting functional precision. Furthermore, using an altered-gravity centrifuge configuration, we found that manual control precision was improved in "hypergravity" and degraded in "hypogravity." These results have potential relevance for postural control, aviation, and spaceflight.
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Affiliation(s)
- Marissa J Rosenberg
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,KBRwyle Science, Technology and Engineering, NASA Johnson Space Center , Houston, Texas.,Center for Space Medicine, Baylor College of Medicine , Houston, Texas
| | - Raquel C Galvan-Garza
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Torin K Clark
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Massachusetts Institute of Technology , Cambridge, Massachusetts.,Department of Otolaryngology, Harvard Medical School , Boston, Massachusetts.,University of Colorado at Boulder , Boulder, Colorado
| | - David P Sherwood
- Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Laurence R Young
- Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Faisal Karmali
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Massachusetts Institute of Technology , Cambridge, Massachusetts.,Department of Otolaryngology, Harvard Medical School , Boston, Massachusetts
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14
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de Souza TAJ, Pereira TC. Caenorhabditis elegans Tolerates Hyperaccelerations up to 400,000 x g. ASTROBIOLOGY 2018; 18:825-833. [PMID: 29746159 DOI: 10.1089/ast.2017.1802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
One of the most important laboratory animal species is the nematode Caenorhabditis elegans, which has been used in a range of research fields such as neurobiology, body development, and molecular biology. The scientific progress obtained by employing C. elegans as a model in these areas has encouraged its use in new fields. One of the new potential applications concerns the biological responses to hyperacceleration stress (g-force), but only a few studies have evaluated the response of multicellular organisms to extreme hypergravity conditions at the order of magnitude 105 x g, which is the theorized force experienced by rocks ejected from Mars (or similar planets). Therefore, we subjected the nematode C. elegans to 400,000 x g (equivalent to that force) and evaluated viability, general morphology, and behavior of C. elegans after exposure to this stress. The metabolic activity of this nematode in response to the gravitational spectrum of 50-400,000 x g was also evaluated by means of the MTT assay. Surprisingly, we found that this organism showed no decrease in viability, no changes in behavior and development, and no drastic metabolic depression after hyperacceleration. Thus, we demonstrated for the first time that this multicellular research model can withstand extremely high g-forces, which prompts the use of C. elegans as a new model for extreme hypergravity. Key Words: Caenorhabditis elegans-Hypergravity-Ultracentrifugation-Acceleration-Panspermia-Astrobiology. Astrobiology 18, 825-833.
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Affiliation(s)
- Tiago Alves Jorge de Souza
- 1 Department of Genetics, Graduate Program in Genetics, FMRP, University of São Paulo , Ribeirao Preto, Brazil
- 2 Department of Biology, FFCLRP, University of São Paulo , Ribeirao Preto, Brazil
| | - Tiago Campos Pereira
- 1 Department of Genetics, Graduate Program in Genetics, FMRP, University of São Paulo , Ribeirao Preto, Brazil
- 2 Department of Biology, FFCLRP, University of São Paulo , Ribeirao Preto, Brazil
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15
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Kheradmand A, Winnick A. Perception of Upright: Multisensory Convergence and the Role of Temporo-Parietal Cortex. Front Neurol 2017; 8:552. [PMID: 29118736 PMCID: PMC5660972 DOI: 10.3389/fneur.2017.00552] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022] Open
Abstract
We inherently maintain a stable perception of the world despite frequent changes in the head, eye, and body positions. Such "orientation constancy" is a prerequisite for coherent spatial perception and sensorimotor planning. As a multimodal sensory reference, perception of upright represents neural processes that subserve orientation constancy through integration of sensory information encoding the eye, head, and body positions. Although perception of upright is distinct from perception of body orientation, they share similar neural substrates within the cerebral cortical networks involved in perception of spatial orientation. These cortical networks, mainly within the temporo-parietal junction, are crucial for multisensory processing and integration that generate sensory reference frames for coherent perception of self-position and extrapersonal space transformations. In this review, we focus on these neural mechanisms and discuss (i) neurobehavioral aspects of orientation constancy, (ii) sensory models that address the neurophysiology underlying perception of upright, and (iii) the current evidence for the role of cerebral cortex in perception of upright and orientation constancy, including findings from the neurological disorders that affect cortical function.
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Affiliation(s)
- Amir Kheradmand
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Otolaryngology – Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ariel Winnick
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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16
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Tamura A, Wada Y, Inui T, Shiotani A. Perceived direction of gravity and the body-axis during static whole body roll-tilt in healthy subjects. Acta Otolaryngol 2017; 137:1057-1062. [PMID: 28537142 DOI: 10.1080/00016489.2017.1328744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE We used the subjective visual vertical (SVV) and two different subjective visual body axis (SVBA) methods to quantify roll-tilt perception under gravity, and investigated the characteristics of these methods during static roll-tilt. In addition, we independently developed a compact device to facilitate evaluation of SVBA in different gravitational environments. METHODS Ten male volunteers participated in this study. We created a roll-tilt environment using a flight simulator in a dark room. The cockpit of the simulator was tilted leftward or rightward (-30°, -20°, -10°, 0°, 10°, 20° and 30°) in each randomly ordered trial. We quantified roll-tilt perception such that the experiment was conducted under 21 different conditions per participant. RESULTS We found no significant differences among the SVV error and the two types of SVBA error. CONCLUSIONS The SVV and the SVBA methods may be useful for evaluating subjective roll-tilt perception.
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Affiliation(s)
- Atsushi Tamura
- Department of Otolaryngology – Head and Neck Surgery, National Defense Medical College, Tokorozawa, Japan
| | - Yoshiro Wada
- Department of Otolaryngology - Head and Neck Surgery, Nara Medical University, Kashihara, Japan
| | | | - Akihiro Shiotani
- Department of Otolaryngology – Head and Neck Surgery, National Defense Medical College, Tokorozawa, Japan
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17
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Jörges B, López-Moliner J. Gravity as a Strong Prior: Implications for Perception and Action. Front Hum Neurosci 2017; 11:203. [PMID: 28503140 PMCID: PMC5408029 DOI: 10.3389/fnhum.2017.00203] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/07/2017] [Indexed: 11/29/2022] Open
Abstract
In the future, humans are likely to be exposed to environments with altered gravity conditions, be it only visually (Virtual and Augmented Reality), or visually and bodily (space travel). As visually and bodily perceived gravity as well as an interiorized representation of earth gravity are involved in a series of tasks, such as catching, grasping, body orientation estimation and spatial inferences, humans will need to adapt to these new gravity conditions. Performance under earth gravity discrepant conditions has been shown to be relatively poor, and few studies conducted in gravity adaptation are rather discouraging. Especially in VR on earth, conflicts between bodily and visual gravity cues seem to make a full adaptation to visually perceived earth-discrepant gravities nearly impossible, and even in space, when visual and bodily cues are congruent, adaptation is extremely slow. We invoke a Bayesian framework for gravity related perceptual processes, in which earth gravity holds the status of a so called “strong prior”. As other strong priors, the gravity prior has developed through years and years of experience in an earth gravity environment. For this reason, the reliability of this representation is extremely high and overrules any sensory information to its contrary. While also other factors such as the multisensory nature of gravity perception need to be taken into account, we present the strong prior account as a unifying explanation for empirical results in gravity perception and adaptation to earth-discrepant gravities.
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Affiliation(s)
- Björn Jörges
- Department of Cognition, Development and Psychology of Education, Faculty of Psychology, Universitat de BarcelonaCatalonia, Spain.,Institut de Neurociències, Universitat de BarcelonaCatalonia, Spain
| | - Joan López-Moliner
- Department of Cognition, Development and Psychology of Education, Faculty of Psychology, Universitat de BarcelonaCatalonia, Spain.,Institut de Neurociències, Universitat de BarcelonaCatalonia, Spain
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18
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Nooij SAE, Nesti A, Bülthoff HH, Pretto P. Perception of rotation, path, and heading in circular trajectories. Exp Brain Res 2016; 234:2323-37. [PMID: 27056085 PMCID: PMC4923114 DOI: 10.1007/s00221-016-4638-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/23/2016] [Indexed: 11/04/2022]
Abstract
When in darkness, humans can perceive the direction and magnitude of rotations and of linear translations in the horizontal plane. The current paper addresses the integrated perception of combined translational and rotational motion, as it occurs when moving along a curved trajectory. We questioned whether the perceived motion through the environment follows the predictions of a self-motion perception model (e.g., Merfeld et al. in J Vestib Res 3:141-161, 1993; Newman in A multisensory observer model for human spatial orientation perception, 2009), which assume linear addition of rotational and translational components. For curved motion in darkness, such models predict a non-veridical motion percept, consisting of an underestimation of the perceived rotation, a distortion of the perceived travelled path, and a bias in the perceived heading (i.e., the perceived instantaneous direction of motion with respect to the body). These model predictions were evaluated in two experiments. In Experiment 1, seven participants were moved along a circular trajectory in darkness while facing the motion direction. They indicated perceived yaw rotation using an online tracking task, and perceived travelled path by drawings. In Experiment 2, the heading was systematically varied, and six participants indicated, in a 2-alternative forced-choice task, whether they perceived facing inward or outward of the circular path. Overall, we found no evidence for the heading bias predicted by the model. This suggests that the sum of the perceived rotational and translational components alone cannot adequately explain the overall perceived motion through the environment. Possibly, knowledge about motion dynamics and familiar stimuli combinations may play an important additional role in shaping the percept.
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Affiliation(s)
- Suzanne A E Nooij
- Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
| | - Alessandro Nesti
- Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Heinrich H Bülthoff
- Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
| | - Paolo Pretto
- Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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19
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Abstract
This chapter provides an introduction to the topic of multisensory integration in balance control in, both, health and disease. One of the best-studied examples is that of visuo-vestibular interaction, which is the ability of the visual system to enhance or suppress the vestibulo-ocular reflex (VOR suppression). Of clinical relevance, examination of VOR suppression is clinically useful because only central, not peripheral, lesions impair VOR suppression. Visual, somatosensory (proprioceptive), and vestibular inputs interact strongly and continuously in the control of upright balance. Experiments with visual motion stimuli show that the visual system generates visually-evoked postural responses that, at least initially, can override vestibular and proprioceptive signals. This paradigm has been useful for the study of the syndrome of visual vertigo or vision-induced dizziness, which can appear after vestibular disease. These patients typically report dizziness when exposed to optokinetic stimuli or visually charged environments, such as supermarkets. The principles of the rehabilitation treatment of these patients, which use repeated exposure to visual motion, are presented. Finally, we offer a diagnostic algorithm in approaching the patient reporting oscillopsia - the illusion of oscillation of the visual environment, which should not be confused with the syndrome mentioned earlier of visual vertigo.
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Affiliation(s)
- A M Bronstein
- Neuro-otology Unit, Imperial College London, Charing Cross Hospital and National Hospital for Neurology and Neurosurgery, London, United Kingdom.
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