1
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Proske U. Joint receptors play a role in position sense after all! J Physiol 2024; 602:3609-3612. [PMID: 38857461 DOI: 10.1113/jp286961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Accepted: 05/29/2024] [Indexed: 06/12/2024] Open
Affiliation(s)
- Uwe Proske
- School of Biomedical Sciences, Monash University, Clayton, VIC, Australia
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2
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Ardonceau V, Poulin-Charronnat B, Bonnet C, Sirandré C, Michel-Colent C. Vertical prism adaptation, but not sound presentation, modulates the visuospatial representation: A manual line-bisection study. Cortex 2024; 177:330-345. [PMID: 38908363 DOI: 10.1016/j.cortex.2024.05.014] [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: 09/12/2023] [Revised: 04/04/2024] [Accepted: 05/21/2024] [Indexed: 06/24/2024]
Abstract
The present study aimed at testing whether vertical prism adaptation (PA) can modulate vertical visuospatial representation, assessed with a vertical manual line-bisection (MLB) task (Experiment 1). In a second time, we wanted to investigate the potential influence of sound presentation during such a task. Sound is a spatially valued element that has previously been reported to modify horizontal visuospatial representation. In Experiment 2, we presented either a high pitch, a low pitch, or no sound during the same MLB as in Experiment 1. With this experiment, we also searched for an eventual interaction between the effect of sound presentation and the potential cognitive aftereffects of vertical PA on visual representation. Both Experiments 1 and 2 were constructed with the same design and conducted with two distinct groups of young healthy right-handed participants. First, we assessed the initial sensorimotor state with an open-loop pointing task, and the initial representational state through a vertical MLB (with addition of sound for Experiment 2). Then participants were submitted to a 16-minute PA procedure and were tested again on the open-loop pointing task and the MLB to assess the aftereffects following prism removal. Our results showed sensorimotor aftereffects following both upward and downward PA, in a direction opposed to the optical deviation used. The early aftereffects measured following PA were symmetrical, but at the end of the experiment the residual aftereffects were smaller following downward PA than upward PA. We also provide a new insight on the aftereffects of vertical PA on visuospatial representation, showing that downward PA (but not upward PA) can produce an upward bias on the manual line-bisection task. This is the first proof of such cognitive aftereffects following vertical PA. However, we found no effect of sound presentation on the vertical visual space representation and no interaction between PA and sound presentation.
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Affiliation(s)
- Vincent Ardonceau
- Inserm U1093 - CAPS, Université de Bourgogne, UFR des Sciences du Sport, Dijon, France.
| | | | | | - Cyril Sirandré
- Inserm U1093 - CAPS, Université de Bourgogne, UFR des Sciences du Sport, Dijon, France
| | - Carine Michel-Colent
- Inserm U1093 - CAPS, Université de Bourgogne, UFR des Sciences du Sport, Dijon, France
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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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Verdel D, Bastide S, Geffard F, Bruneau O, Vignais N, Berret B. Reoptimization of single-joint motor patterns to non-Earth gravity torques induced by a robotic exoskeleton. iScience 2023; 26:108350. [PMID: 38026148 PMCID: PMC10665922 DOI: 10.1016/j.isci.2023.108350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/29/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Gravity is a ubiquitous component of our environment that we have learned to optimally integrate in movement control. Yet, altered gravity conditions arise in numerous applications from space exploration to rehabilitation, thereby pressing the sensorimotor system to adapt. Here, we used a robotic exoskeleton to reproduce the elbow joint-level effects of arbitrary gravity fields ranging from 1g to -1g, passing through Mars- and Moon-like gravities, and tested whether humans can reoptimize their motor patterns accordingly. By comparing the motor patterns of actual arm movements with those predicted by an optimal control model, we show that our participants (N = 61 ) adapted optimally to each gravity-like torque. These findings suggest that the joint-level effects of a large range of gravities can be efficiently apprehended by humans, thus opening new perspectives in arm weight support training in manipulation tasks, whether it be for patients or astronauts.
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Affiliation(s)
- Dorian Verdel
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Simon Bastide
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | | | - Olivier Bruneau
- LURPA, Mechanical Engineering Department, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Nicolas Vignais
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Bastien Berret
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
- Institut Universitaire de France, Paris, France
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5
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Verdel D, Bruneau O, Sahm G, Vignais N, Berret B. The value of time in the invigoration of human movements when interacting with a robotic exoskeleton. SCIENCE ADVANCES 2023; 9:eadh9533. [PMID: 37729420 PMCID: PMC10511201 DOI: 10.1126/sciadv.adh9533] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/18/2023] [Indexed: 09/22/2023]
Abstract
Time and effort are thought to be subjectively balanced during the planning of goal-directed actions, thereby setting the vigor of volitional movements. Theoretical models predicted that the value of time should then amount to high levels of effort. However, the time-effort trade-off has so far only been studied for a narrow range of efforts. To investigate the extent to which humans can invest in a time-saving effort, we used a robotic exoskeleton to substantially vary the energetic cost associated with a certain vigor during reaching movements. In this situation, minimizing the time-effort trade-off should lead to high and low human efforts for upward and downward movements, respectively. Consistently, all participants expended substantial amounts of energy upward and remained essentially inactive by harnessing the work of gravity downward, while saving time in both cases. A common time-effort trade-off may therefore determine the vigor of reaching movements for a wide range of efforts.
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Affiliation(s)
- Dorian Verdel
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Olivier Bruneau
- LURPA, Mechanical Engineering Department, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Guillaume Sahm
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Nicolas Vignais
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Bastien Berret
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
- Institut Universitaire de France, Paris, France
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6
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Proske U, Weber BM. Proprioceptive disturbances in weightlessness revisited. NPJ Microgravity 2023; 9:64. [PMID: 37567869 PMCID: PMC10421854 DOI: 10.1038/s41526-023-00318-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
The senses of limb position and movement become degraded in low gravity. One explanation is a gravity-dependent loss of fusimotor activity. In low gravity, position and movement sense accuracy can be recovered if elastic bands are stretched across the joint. Recent studies using instrumented joysticks have confirmed that aiming and tracking accuracy can be recovered in weightlessness by changing viscous and elastic characteristics of the joystick. It has been proposed that the muscle spindle signal, responsible for generating position sense in the mid-range of joint movement, is combined with input from joint receptors near the limits of joint movement to generate a position signal that covers the full working range of the joint. Here it is hypothesised that in low gravity joint receptors become unresponsive because of the loss of forces acting on the joint capsule. This leads to a loss of position and movement sense which can be recovered by imposing elastic forces across the joint.
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Affiliation(s)
- Uwe Proske
- School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Bernhard M Weber
- Institute of Robotics and Mechatronics, German Aerospace Center, 82234, Wessling, Germany.
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7
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Stahn AC, Bucher D, Zu Eulenburg P, Denise P, Smith N, Pagnini F, White O. Paving the way to better understand the effects of prolonged spaceflight on operational performance and its neural bases. NPJ Microgravity 2023; 9:59. [PMID: 37524737 PMCID: PMC10390562 DOI: 10.1038/s41526-023-00295-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 06/15/2023] [Indexed: 08/02/2023] Open
Abstract
Space exploration objectives will soon move from low Earth orbit to distant destinations like Moon and Mars. The present work provides an up-to-date roadmap that identifies critical research gaps related to human behavior and performance in altered gravity and space. The roadmap summarizes (1) key neurobehavioral challenges associated with spaceflight, (2) the need to consider sex as a biological variable, (3) the use of integrative omics technologies to elucidate mechanisms underlying changes in the brain and behavior, and (4) the importance of understanding the neural representation of gravity throughout the brain and its multisensory processing. We then highlight the need for a variety of target-specific countermeasures, and a personalized administration schedule as two critical strategies for mitigating potentially adverse effects of spaceflight on the central nervous system and performance. We conclude with a summary of key priorities for the roadmaps of current and future space programs and stress the importance of new collaborative strategies across agencies and researchers for fostering an integrative cross- and transdisciplinary approach from cells, molecules to neural circuits and cognitive performance. Finally, we highlight that space research in neurocognitive science goes beyond monitoring and mitigating risks in astronauts but could also have significant benefits for the population on Earth.
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Affiliation(s)
- A C Stahn
- Unit of Experimental Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Physiology, Berlin, Germany.
| | - D Bucher
- IZN-Neurobiology, University of Heidelberg, Heidelberg, Germany
| | - P Zu Eulenburg
- Institute for Neuroradiology & German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-University Munich, Munich, Germany
| | - P Denise
- Normandie Univ. UNICAEN, INSERM, COMETE, CYCERON, Caen, France
| | - N Smith
- Protective Security and Resilience Centre, Coventry University, Coventry, United Kingdom
| | - F Pagnini
- Department of Psychology, Università Cattolica del Sacro Cuore, Milan, Italy
| | - O White
- Université de Bourgogne INSERM-U1093 Cognition, Action, and Sensorimotor Plasticity, Dijon, France.
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8
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Malaya CA, Parikh PJ, Smith DL, Riaz A, Chandrasekaran S, Layne CS. Effects of simulated hypo-gravity on lower limb kinematic and electromyographic variables during anti-gravitational treadmill walking. Front Physiol 2023; 14:1141015. [PMID: 37362436 PMCID: PMC10285399 DOI: 10.3389/fphys.2023.1141015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Introduction: This study investigated kinematic and EMG changes in gait across simulated gravitational unloading levels between 100% and 20% of normal body weight. This study sought to identify if each level of unloading elicited consistent changes-particular to that percentage of normal body weight-or if the changes seen with unloading could be influenced by the previous level(s) of unloading. Methods: 15 healthy adult participants (26.3 ± 2.5 years; 53% female) walked in an Alter-G anti-gravity treadmill unloading system (mean speed: 1.49 ± 0.37 mph) for 1 min each at 100%, 80%, 60%, 40% and 20% of normal body weight, before loading back to 100% in reverse order. Lower-body kinematic data were captured by inertial measurement units, and EMG data were collected from the rectus femoris, biceps femoris, medial gastrocnemius, and anterior tibialis. Data were compared across like levels of load using repeated measures ANOVA and statistical parametric mapping. Difference waveforms for adjacent levels were created to examine the rate of change between different unloading levels. Results: This study found hip, knee, and ankle kinematics as well as activity in the rectus femoris, and medial gastrocnemius were significantly different at the same level of unloading, having arrived from a higher, or lower level of unloading. There were no significant changes in the kinematic difference waveforms, however the waveform representing the change in EMG between 100% and 80% load was significantly different from all other levels. Discussion: This study found that body weight unloading from 100% to 20% elicited distinct responses in the medial gastrocnemius, as well as partly in the rectus femoris. Hip, knee, and ankle kinematics were also affected differentially by loading and unloading, especially at 40% of normal body weight. These findings suggest the previous level of gravitational load is an important factor to consider in determining kinematic and EMG responses to the current level during loading and unloading below standard g. Similarly, the rate of change in kinematics from 100% to 20% appears to be linear, while the rate of change in EMG was non-linear. This is of particular interest, as it suggests that kinematic and EMG measures decouple with unloading and may react to unloading uniquely.
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Affiliation(s)
- Christopher A. Malaya
- Center for Neuromotor and Biomechanics Research, Department of Health and Human Performance, University of Houston, Houston, TX, United States
- Grail Laboratory, Parker University, Dallas, TX, United States
| | - Pranav J. Parikh
- Center for Neuromotor and Biomechanics Research, Department of Health and Human Performance, University of Houston, Houston, TX, United States
| | - Dean L. Smith
- Nutrition and Health, Department of Kinesiology, Miami University, Oxford, OH, United States
| | - Arshia Riaz
- Center for Neuromotor and Biomechanics Research, Department of Health and Human Performance, University of Houston, Houston, TX, United States
| | - Subhalakshmi Chandrasekaran
- Center for Neuromotor and Biomechanics Research, Department of Health and Human Performance, University of Houston, Houston, TX, United States
| | - Charles S. Layne
- Center for Neuromotor and Biomechanics Research, Department of Health and Human Performance, University of Houston, Houston, TX, United States
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9
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Weber BM, Schätzle S, Stelzer M. Aiming performance during spaceflight: Individual adaptation to microgravity and the benefits of haptic support. APPLIED ERGONOMICS 2022; 103:103791. [PMID: 35588558 DOI: 10.1016/j.apergo.2022.103791] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
Sensorimotor performance is known to deteriorate during spaceflight. Prior research for instance documented that targeted arm motions are performed slower and less precise in microgravity conditions. This article describes an experiment on aiming performance during different stages of a space mission. Moreover, the influence of different haptic settings of the human-machine interface (HMI) was explored. Two separate studies are presented in which the same aiming tasks were performed with a force feedback joystick: 1) A terrestrial study (N = 20) to explore time and haptic setting effects and 2) a space experiment (N = 3) with a pre-mission session, three mission sessions on board the ISS (2, 4, and 6 weeks in space), and a post-mission session. Results showed that sensorimotor performance was mainly affected in the initial phase of exposure to microgravity and this effect was moderated by astronauts' sensorimotor skills. Providing low stiffness at the HMI, however, proved to be an effective measure to maintain aiming precision in microgravity.
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Affiliation(s)
- Bernhard M Weber
- German Aerospace Center, Institute of Robotics and Mechatronics, 82234, Wessling, Germany.
| | - Simon Schätzle
- Sensor-Technik Wiedemann GmbH, 87600, Kaufbeuren, Germany
| | - Martin Stelzer
- German Aerospace Center, Institute of Robotics and Mechatronics, 82234, Wessling, Germany
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10
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Weber B, Stelzer M. Sensorimotor impairments during spaceflight: Trigger mechanisms and haptic assistance. FRONTIERS IN NEUROERGONOMICS 2022; 3:959894. [PMID: 38235445 PMCID: PMC10790879 DOI: 10.3389/fnrgo.2022.959894] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/18/2022] [Indexed: 01/19/2024]
Abstract
In a few years, manned space missions are planned in which the sensorimotor performance of humans will be of outstanding importance. However, research has repeatedly shown that human sensorimotor function can be impaired under conditions of microgravity. One way to compensate for these impairments is haptic feedback provided by the human-machine interface. In the current series of studies, sensorimotor performance was measured in basic aiming and tracking tasks. These tasks had to be performed using a force feedback joystick with different haptic settings (three spring stiffnesses, two dampings, two virtual masses, and no haptics). In two terrestrial studies, we investigated (1) the effects of cognitive load on performance in a dual-task paradigm (N = 10) and (2) which learning effects can be expected in these tasks in a longitudinal study design (N = 20). In the subsequent space study (N = 3 astronauts), the influence of microgravity and haptic settings of the joystick were investigated. For this purpose, three mission sessions after 2, 4, and 6 weeks on board the International Space Station (ISS), as well as terrestrial pre- and post-flight sessions, were conducted. The results of the studies indicated that (1) additional cognitive load led to longer reaction times during aiming and increased tracking error while aiming precision was not affected. (2) Significant learning effects were evident for most measures in the study on time effects. (3) Contrary to the expected learning trend, microgravity impaired the aiming precision performance of all astronauts in the initial phase of adaptation (2 weeks in space). No other significant effects were found. Intriguingly, these performance decrements could be compensated for with low to medium spring stiffness and virtual mass. The general result pattern provides further evidence that distorted proprioception during early adaptation to microgravity conditions is one main mechanism underlying sensorimotor impairment.
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Affiliation(s)
- Bernhard Weber
- Institute of Robotics and Mechatronics, German Aerospace Center, Oberpfaffenhofen, Germany
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11
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Arshad I, Ferrè ER. Express: Cognition in Zero Gravity: Effects of Non-Terrestrial Gravity on Human Behaviour. Q J Exp Psychol (Hove) 2022; 76:979-994. [PMID: 35786100 PMCID: PMC10119906 DOI: 10.1177/17470218221113935] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As humanity prepares for deep space exploration, understanding the impact of spaceflight on bodily physiology is critical. While the effects of non-terrestrial gravity on the body are well established, little is known about its impact on human behaviour and cognition. Astronauts often describe dramatic alterations in sensorimotor functioning, including orientation, postural control and balance. Changes in cognitive functioning as well as in socio-affective processing have also been observed. Here we have reviewed the key literature and explored the impact of non-terrestrial gravity across three key functional domains: sensorimotor, cognition, and socio-affective processing. We have proposed a neuroanatomical model to account for the effects of non-terrestrial gravity in these domains. Understanding the impact of non-terrestrial gravity on human behaviour has never been more timely and it will help mitigate against risks in both commercial and non-commercial spaceflight.
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Affiliation(s)
- Iqra Arshad
- Department of Psychology, Royal Holloway University of London, Egham, UK 3162
| | - Elisa Raffaella Ferrè
- Department of Psychological Sciences, Birkbeck University of London, London, UK 3162
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12
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Weber B, Proske U. Limb position sense and sensorimotor performance under conditions of weightlessness. LIFE SCIENCES IN SPACE RESEARCH 2022; 32:63-69. [PMID: 35065762 DOI: 10.1016/j.lssr.2021.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 06/14/2023]
Abstract
This is a review of the current state of knowledge of the effects of weightlessness on human proprioception. Two aspects have been highlighted: the sense of limb position and performance in sensorimotor tasks. For the sense of position, an important consideration is that there probably exists more than one sense: one measured in a blindfolded, two-limb position matching task, the other, by pointing to the perceived position of a hidden limb. There is evidence that these two senses are supported by distinct central projection pathways. When assessing the effects of weightlessness this must be considered. Whether there is a role for vestibular influences on position sense during changes in gravitational forces is an issue for future experiments. A consideration that has proved helpful for the study of sensorimotor tasks under conditions of weightlessness is to examine the performance of subjects who have lost their proprioceptive senses, either congenitally, or later in life, as a result of disease. In weightlessness, normal subjects appear to have particular difficulties with feedback-controlled tasks. A major factor is the influence of vision on performance. In addition, the stress of working in a weightless environment leads to additional cognitive load, making the execution of even simple everyday tasks difficult.
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Affiliation(s)
- Bernhard Weber
- Institute of Robotics and Mechatronics, German Aerospace Center, Oberpfaffenhofen, 82234 Wessling, Germany.
| | - Uwe Proske
- Department of Physiology, Monash University, Clayton, VIC 3800, Australia
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13
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Jamšek M, Kunavar T, Blohm G, Nozaki D, Papaxanthis C, White O, Babič J. Effects of Simulated Microgravity and Hypergravity Conditions on Arm Movements in Normogravity. Front Neural Circuits 2021; 15:750176. [PMID: 34970122 PMCID: PMC8712641 DOI: 10.3389/fncir.2021.750176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
The human sensorimotor control has evolved in the Earth's environment where all movement is influenced by the gravitational force. Changes in this environmental force can severely impact the performance of arm movements which can be detrimental in completing certain tasks such as piloting or controlling complex vehicles. For this reason, subjects that are required to perform such tasks undergo extensive training procedures in order to minimize the chances of failure. We investigated whether local gravity simulation of altered gravitational conditions on the arm would lead to changes in kinematic parameters comparable to the full-body experience of microgravity and hypergravity onboard a parabolic flight. To see if this would be a feasible approach for on-ground training of arm reaching movements in altered gravity conditions we developed a robotic device that was able to apply forces at the wrist in order to simulate micro- or hypergravity conditions for the arm while subjects performed pointing movements on a touch screen. We analyzed and compared the results of several kinematic parameters along with muscle activity using this system with data of the same subjects being fully exposed to microgravity and hypergravity conditions on a parabolic flight. Both in our simulation and in-flight, we observed a significant increase in movement durations in microgravity conditions and increased velocities in hypergravity for upward movements. Additionally, we noted a reduced accuracy of pointing both in-flight and in our simulation. These promising results suggest, that locally simulated altered gravity can elicit similar changes in some movement characteristics for arm reaching movements. This could potentially be exploited as a means of developing devices such as exoskeletons to aid in training individuals prior to undertaking tasks in changed gravitational conditions.
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Affiliation(s)
- Marko Jamšek
- Laboratory for Neuromechanics and Biorobotics, Jožef Stefan Institute, Department of Automatics, Biocybernetics and Robotics, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Tjaša Kunavar
- Laboratory for Neuromechanics and Biorobotics, Jožef Stefan Institute, Department of Automatics, Biocybernetics and Robotics, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Gunnar Blohm
- Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Daichi Nozaki
- Division of Physical and Health Education, Graduate School of Education, The University of Tokyo, Tokyo, Japan
| | - Charalambos Papaxanthis
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Olivier White
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Jan Babič
- Laboratory for Neuromechanics and Biorobotics, Jožef Stefan Institute, Department of Automatics, Biocybernetics and Robotics, Ljubljana, Slovenia
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
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14
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Gravano S, Lacquaniti F, Zago M. Mental imagery of object motion in weightlessness. NPJ Microgravity 2021; 7:50. [PMID: 34862387 PMCID: PMC8642442 DOI: 10.1038/s41526-021-00179-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/27/2021] [Indexed: 12/23/2022] Open
Abstract
Mental imagery represents a potential countermeasure for sensorimotor and cognitive dysfunctions due to spaceflight. It might help train people to deal with conditions unique to spaceflight. Thus, dynamic interactions with the inertial motion of weightless objects are only experienced in weightlessness but can be simulated on Earth using mental imagery. Such training might overcome the problem of calibrating fine-grained hand forces and estimating the spatiotemporal parameters of the resulting object motion. Here, a group of astronauts grasped an imaginary ball, threw it against the ceiling or the front wall, and caught it after the bounce, during pre-flight, in-flight, and post-flight experiments. They varied the throwing speed across trials and imagined that the ball moved under Earth's gravity or weightlessness. We found that the astronauts were able to reproduce qualitative differences between inertial and gravitational motion already on ground, and further adapted their behavior during spaceflight. Thus, they adjusted the throwing speed and the catching time, equivalent to the duration of virtual ball motion, as a function of the imaginary 0 g condition versus the imaginary 1 g condition. Arm kinematics of the frontal throws further revealed a differential processing of imagined gravity level in terms of the spatial features of the arm and virtual ball trajectories. We suggest that protocols of this kind may facilitate sensorimotor adaptation and help tuning vestibular plasticity in-flight, since mental imagery of gravitational motion is known to engage the vestibular cortex.
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Affiliation(s)
- Silvio Gravano
- grid.417778.a0000 0001 0692 3437Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy ,grid.6530.00000 0001 2300 0941Department of Systems Medicine and Center of Space BioMedicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179, Rome, Italy. .,Department of Systems Medicine and Center of Space BioMedicine, University of Rome Tor Vergata, 00133, Rome, Italy.
| | - Myrka Zago
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179, Rome, Italy. .,Department of Civil Engineering and Computer Science Engineering & Center of Space BioMedicine, University of Rome Tor Vergata, 00133, Rome, Italy.
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15
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Kunavar T, Jamšek M, Barbiero M, Blohm G, Nozaki D, Papaxanthis C, White O, Babič J. Effects of Local Gravity Compensation on Motor Control During Altered Environmental Gravity. Front Neural Circuits 2021; 15:750267. [PMID: 34744639 PMCID: PMC8568321 DOI: 10.3389/fncir.2021.750267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/30/2021] [Indexed: 11/18/2022] Open
Abstract
Our sensorimotor control is well adapted to normogravity environment encountered on Earth and any change in gravity significantly disturbs our movement. In order to produce appropriate motor commands for aimed arm movements such as pointing or reaching, environmental changes have to be taken into account. This adaptation is crucial when performing successful movements during microgravity and hypergravity conditions. To mitigate the effects of changing gravitational levels, such as the changed movement duration and decreased accuracy, we explored the possible beneficial effects of gravity compensation on movement. Local gravity compensation was achieved using a motorized robotic device capable of applying precise forces to the subject’s wrist that generated a normogravity equivalent torque at the shoulder joint during periods of microgravity and hypergravity. The efficiency of the local gravity compensation was assessed with an experiment in which participants performed a series of pointing movements toward the target on a screen during a parabolic flight. We compared movement duration, accuracy, movement trajectory, and muscle activations of movements during periods of microgravity and hypergravity with conditions when local gravity compensation was provided. The use of local gravity compensation at the arm mitigated the changes in movement duration, accuracy, and muscle activity. Our results suggest that the use of such an assistive device helps with movements during unfamiliar environmental gravity.
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Affiliation(s)
- Tjasa Kunavar
- Laboratory for Neuromechanics and Biorobotics, Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Marko Jamšek
- Laboratory for Neuromechanics and Biorobotics, Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Marie Barbiero
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France.,Centre National d'Etudes Spatiales, Paris, France
| | - Gunnar Blohm
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
| | - Daichi Nozaki
- Division of Physical and Health Education, Graduate School of Education, The University of Tokyo, Tokyo, Japan
| | - Charalambos Papaxanthis
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Olivier White
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Jan Babič
- Laboratory for Neuromechanics and Biorobotics, Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
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16
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Carriot J, Mackrous I, Cullen KE. Challenges to the Vestibular System in Space: How the Brain Responds and Adapts to Microgravity. Front Neural Circuits 2021; 15:760313. [PMID: 34803615 PMCID: PMC8595211 DOI: 10.3389/fncir.2021.760313] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
In the next century, flying civilians to space or humans to Mars will no longer be a subject of science fiction. The altered gravitational environment experienced during space flight, as well as that experienced following landing, results in impaired perceptual and motor performance-particularly in the first days of the new environmental challenge. Notably, the absence of gravity unloads the vestibular otolith organs such that they are no longer stimulated as they would be on earth. Understanding how the brain responds initially and then adapts to altered sensory input has important implications for understanding the inherent abilities as well as limitations of human performance. Space-based experiments have shown that altered gravity causes structural and functional changes at multiple stages of vestibular processing, spanning from the hair cells of its sensory organs to the Purkinje cells of the vestibular cerebellum. Furthermore, ground-based experiments have established the adaptive capacity of vestibular pathways and neural mechanism that likely underlie this adaptation. We review these studies and suggest that the brain likely uses two key strategies to adapt to changes in gravity: (i) the updating of a cerebellum-based internal model of the sensory consequences of gravity; and (ii) the re-weighting of extra-vestibular information as the vestibular system becomes less (i.e., entering microgravity) and then again more reliable (i.e., return to earth).
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Affiliation(s)
- Jérome Carriot
- Department of Physiology, McGill University, Montreal, QC, Canada
| | | | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
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17
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Gallagher M, Kearney B, Ferrè ER. Where is my hand in space? The internal model of gravity influences proprioception. Biol Lett 2021; 17:20210115. [PMID: 34062087 DOI: 10.1098/rsbl.2021.0115] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Knowing where our limbs are in space is crucial for a successful interaction with the external world. Joint position sense (JPS) relies on both cues from muscle spindles and joint mechanoreceptors, as well as the effort required to move. However, JPS may also rely on the perceived external force on the limb, such as the gravitational field. It is well known that the internal model of gravity plays a large role in perception and behaviour. Thus, we have explored whether direct vestibular-gravitational cues could influence JPS. Participants passively estimated the position of their hand while they were upright and therefore aligned with terrestrial gravity, or pitch-tilted 45° backwards from gravity. Overall participants overestimated the position of their hand in both upright and tilted postures; however, the proprioceptive bias was significantly reduced when participants were tilted. Our findings therefore suggest that the internal model of gravity may influence and update JPS in order to allow the organism to interact with the environment.
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Affiliation(s)
- Maria Gallagher
- Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.,School of Psychology, Cardiff University, Cardiff CF10 3AT, UK
| | - Breanne Kearney
- Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK
| | - Elisa Raffaella Ferrè
- Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK
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18
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Weber B, Riecke C, Stulp F. Sensorimotor impairment and haptic support in microgravity. Exp Brain Res 2021; 239:967-981. [PMID: 33464389 PMCID: PMC7943528 DOI: 10.1007/s00221-020-06024-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/17/2020] [Indexed: 11/24/2022]
Abstract
Future space missions envisage human operators teleoperating robotic systems from orbital spacecraft. A potential risk for such missions is the observation that sensorimotor performance deteriorates during spaceflight. This article describes an experiment on sensorimotor performance in two-dimensional manual tracking during different stages of a space mission. We investigated whether there are optimal haptic settings of the human-machine interface for microgravity conditions. Two empirical studies using the same task paradigm with a force feedback joystick with different haptic settings (no haptics, four spring stiffnesses, two motion dampings, three masses) are presented in this paper. (1) A terrestrial control study (\documentclass[12pt]{minimal}
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\begin{document}$$N=20$$\end{document}N=20 subjects) with five experimental sessions to explore potential learning effects and interactions with haptic settings. (2) A space experiment (\documentclass[12pt]{minimal}
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\begin{document}$$N=3$$\end{document}N=3 cosmonauts) with a pre-mission, three mission sessions on board the ISS (2, 4, and 6 weeks in space), and a post-mission session. Results provide evidence that distorted proprioception significantly affects motion smoothness in the early phase of adaptation to microgravity, while the magnitude of this effect was moderated by cosmonauts’ sensorimotor capabilities. Moreover, this sensorimotor impairment can be compensated by providing subtle haptic cues. Specifically, low damping improved tracking smoothness for both motion directions (sagittal and transverse motion plane) and low stiffness improved performance in the transverse motion plane.
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Affiliation(s)
- Bernhard Weber
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany.
| | - Cornelia Riecke
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany
| | - Freek Stulp
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany
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19
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Weber B, Panzirsch M, Stulp F, Schneider S. Sensorimotor performance and haptic support in simulated weightlessness. Exp Brain Res 2020; 238:2373-2384. [PMID: 32767066 PMCID: PMC7496033 DOI: 10.1007/s00221-020-05898-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/27/2020] [Indexed: 11/26/2022]
Abstract
The success of many space missions critically depends on human capabilities and performance. Yet, it is known that sensorimotor performance is degraded under conditions of weightlessness. Therefore, astronauts prepare for their missions in simulated weightlessness under water. In the present study, we investigated sensorimotor performance in simulated weightlessness (induced by shallow water immersion) and whether performance can be improved by choosing appropriate haptic settings of the human-machine interface (e.g., motion damping). Twenty-two participants performed basic aiming and tracking tasks with a force feedback joystick under water and on land and with different haptic settings of the joystick (no haptics, three spring stiffnesses, and two motion dampings). While higher resistive forces should be avoided for rapid aiming tasks in simulated weightlessness, tracking performance is best with higher motions damping in both land and water setups, although the performance losses due to water immersion cannot be compensated. The overall result pattern also provides insights into the causal mechanism behind the slowing effect during aiming motions and decreased accuracy of tracking motions in simulated weightlessness. Findings provide evidence that distorted proprioception due to altered muscle spindle activity seemingly is the main trigger of impaired sensorimotor performance in simulated weightlessness.
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Affiliation(s)
- Bernhard Weber
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany.
| | - Michael Panzirsch
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany
| | - Freek Stulp
- German Aerospace Center, Institute of Robotics and Mechatronics, Oberpfaffenhofen, Germany
| | - Stefan Schneider
- Institute of Movement and Neurosciences, German Sport University, Cologne, Germany
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20
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Bringoux L, Macaluso T, Sainton P, Chomienne L, Buloup F, Mouchnino L, Simoneau M, Blouin J. Double-Step Paradigm in Microgravity: Preservation of Sensorimotor Flexibility in Altered Gravitational Force Field. Front Physiol 2020; 11:377. [PMID: 32390872 PMCID: PMC7193114 DOI: 10.3389/fphys.2020.00377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 03/30/2020] [Indexed: 12/02/2022] Open
Abstract
The way we can correct our ongoing movements to sudden and unforeseen perturbations is key to our ability to rapidly adjust our behavior to novel environmental demands. Referred to as sensorimotor flexibility, this ability can be assessed by the double-step paradigm in which participants must correct their ongoing arm movements to reach targets that unexpectedly change location (i.e., target jump). While this type of corrections has been demonstrated in normogravity in the extent of reasonable spatiotemporal constraints underpinning the target jumps, less is known about sensorimotor flexibility in altered gravitational force fields. We thus aimed to assess sensorimotor flexibility by comparing online arm pointing corrections observed during microgravity episodes of parabolic flights with normogravity standards. Seven participants were asked to point as fast and as accurately as possible toward one of two visual targets with their right index finger. The targets were aligned vertically in the mid-sagittal plane and were separated by 10 cm. In 20% of the trials, the initially illuminated lower target was switched off at movement onset while the upper target was concomitantly switched on prompting participants to change the trajectory of their ongoing movements. Results showed that, both in normogravity and microgravity, participants successfully performed the pointing task including when the target jumped unexpectedly (i.e., comparable success rate). Most importantly, no significant difference was found in target jump trials regarding arm kinematics between both gravitational environments, neither in terms of peak velocity, relative deceleration duration, peak acceleration or time to peak acceleration. Using inverse dynamics based on experimental and anthropometrical data, we demonstrated that the shoulder torques for accelerating and decelerating the vertical arm movements substantially differed between microgravity and normogravity. Our data therefore highlight the capacity of the central nervous system to perform very fast neuromuscular adjustments that are adapted to the gravitational constraints. We discuss our findings by considering the contribution of feedforward and feedback mechanisms in the online control of arm pointing movements.
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Affiliation(s)
- L Bringoux
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - T Macaluso
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - P Sainton
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - L Chomienne
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - F Buloup
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - L Mouchnino
- Aix Marseille Univ, CNRS, LNC, Marseille, France
| | - M Simoneau
- Département de Kinésiologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada.,Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS) du CIUSSS de la Capitale Nationale, Quebec, QC, Canada
| | - J Blouin
- Aix Marseille Univ, CNRS, LNC, Marseille, France
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21
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White O, Gaveau J, Bringoux L, Crevecoeur F. The gravitational imprint on sensorimotor planning and control. J Neurophysiol 2020; 124:4-19. [PMID: 32348686 DOI: 10.1152/jn.00381.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Humans excel at learning complex tasks, and elite performers such as musicians or athletes develop motor skills that defy biomechanical constraints. All actions require the movement of massive bodies. Of particular interest in the process of sensorimotor learning and control is the impact of gravitational forces on the body. Indeed, efficient control and accurate internal representations of the body configuration in space depend on our ability to feel and anticipate the action of gravity. Here we review studies on perception and sensorimotor control in both normal and altered gravity. Behavioral and modeling studies together suggested that the nervous system develops efficient strategies to take advantage of gravitational forces across a wide variety of tasks. However, when the body was exposed to altered gravity, the rate and amount of adaptation exhibited substantial variation from one experiment to another and sometimes led to partial adjustment only. Overall, these results support the hypothesis that the brain uses a multimodal and flexible representation of the effect of gravity on our body and movements. Future work is necessary to better characterize the nature of this internal representation and the extent to which it can adapt to novel contexts.
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Affiliation(s)
- O White
- INSERM UMR1093-CAPS, UFR des Sciences du Sport, Université Bourgogne Franche-Comté, Dijon, France
| | - J Gaveau
- INSERM UMR1093-CAPS, UFR des Sciences du Sport, Université Bourgogne Franche-Comté, Dijon, France
| | - L Bringoux
- Institut des Sciences du Mouvement, CNRS, Aix Marseille Université, Marseille, France
| | - F Crevecoeur
- Institute of Communication and Information Technologies, Electronics and Applied Mathematics (ICTEAM), UCLouvain, Belgium.,Institute of Neuroscience (IoNS), UCLouvain, Belgium
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22
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Poirier G, Papaxanthis C, Mourey F, Gaveau J. Motor Planning of Vertical Arm Movements in Healthy Older Adults: Does Effort Minimization Persist With Aging? Front Aging Neurosci 2020; 12:37. [PMID: 32161533 PMCID: PMC7052522 DOI: 10.3389/fnagi.2020.00037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/04/2020] [Indexed: 01/01/2023] Open
Abstract
Several sensorimotor modifications are known to occur with aging, possibly leading to adverse outcomes such as falls. Recently, some of those modifications have been proposed to emerge from motor planning deteriorations. Motor planning of vertical movements is thought to engage an internal model of gravity to anticipate its mechanical effects on the body-limbs and thus to genuinely produce movements that minimize muscle effort. This is supported, amongst other results, by direction-dependent kinematics where relative durations to peak accelerations and peak velocity are shorter for upward than for downward movements. The present study compares the motor planning of fast and slow vertical arm reaching movements between 18 young (24 ± 3 years old) and 17 older adults (70 ± 5 years old). We found that older participants still exhibit strong directional asymmetries (i.e., differences between upward and downward movements), indicating that optimization processes during motor planning persist with healthy aging. However, the size of these differences was increased in older participants, indicating that gravity-related motor planning changes with age. We discuss this increase as the possible result of an overestimation of gravity torque or increased weight of the effort cost in the optimization process. Overall, these results support the hypothesis that feedforward processes and, more precisely, optimal motor planning, remain active with healthy aging.
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23
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Doustan M, Namazizadeh M, Sheikh M, Naghdi N. Evaluation of learning of asymmetrical bimanual tasks and transfer to converse pattern: Load, temporal and spatial asymmetry of hand movements. ACTA GYMNICA 2019. [DOI: 10.5507/ag.2019.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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24
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Exercise, fatigue and proprioception: a retrospective. Exp Brain Res 2019; 237:2447-2459. [DOI: 10.1007/s00221-019-05634-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/17/2019] [Indexed: 10/26/2022]
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25
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Guillot A, Debarnot U. Benefits of Motor Imagery for Human Space Flight: A Brief Review of Current Knowledge and Future Applications. Front Physiol 2019; 10:396. [PMID: 31031635 PMCID: PMC6470189 DOI: 10.3389/fphys.2019.00396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/21/2019] [Indexed: 12/12/2022] Open
Abstract
Motor imagery (MI) is arguably one of the most remarkable capacities of the human mind. There is now strong experimental evidence that MI contributes to substantial improvements in motor learning and performance. The therapeutic benefits of MI in promoting motor recovery among patients with motor impairments have also been reported. Despite promising theoretical and experimental findings, the utility of MI in adapting to unusual conditions, such as weightlessness during space flight, has received far less attention. In this review, we consider how, why, where, and when MI might be used by astronauts, and further evaluate the optimum MI content. Practically, we suggest that MI might be performed before, during, and after exposure to microgravity, respectively, to prepare for the rapid changes in gravitational forces after launch and to reduce the adverse effects of weightlessness exposition. Moreover, MI has potential role in facilitating re-adaptation when returning to Earth after long exposure to microgravity. Suggestions for further research include a focus on the multi-sensory aspects of MI, the requirement to use temporal characteristics as a measurement tool, and to account for the knowledge-base or metacognitive processes underlying optimal MI implementation.
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Affiliation(s)
- Aymeric Guillot
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, Villeurbanne, France.,Institut Universitaire de France, Paris, France
| | - Ursula Debarnot
- Inter-University Laboratory of Human Movement Biology-EA 7424, University of Lyon, University Claude Bernard Lyon 1, Villeurbanne, France
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26
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Macaluso T, Bourdin C, Buloup F, Mille ML, Sainton P, Sarlegna FR, Vercher JL, Bringoux L. Sensorimotor Reorganizations of Arm Kinematics and Postural Strategy for Functional Whole-Body Reaching Movements in Microgravity. Front Physiol 2017; 8:821. [PMID: 29104544 PMCID: PMC5654841 DOI: 10.3389/fphys.2017.00821] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/05/2017] [Indexed: 11/13/2022] Open
Abstract
Understanding the impact of weightlessness on human behavior during the forthcoming long-term space missions is of critical importance, especially when considering the efficiency of goal-directed movements in these unusual environments. Several studies provided a large set of evidence that gravity is taken into account during the planning stage of arm reaching movements to optimally anticipate its consequence upon the moving limbs. However, less is known about sensorimotor changes required to face weightless environments when individuals have to perform fast and accurate goal-directed actions with whole-body displacement. We thus aimed at characterizing kinematic features of whole-body reaching movements in microgravity, involving high spatiotemporal constraints of execution, to question whether and how humans are able to maintain the performance of a functional behavior in the standards of normogravity execution. Seven participants were asked to reach as fast and as accurately as possible visual targets while standing during microgravity episodes in parabolic flight. Small and large targets were presented either close or far from the participants (requiring, in the latter case, additional whole-body displacement). Results reported that participants successfully performed the reaching task with general temporal features of movement (e.g., movement speed) close to land observations. However, our analyses also demonstrated substantial kinematic changes related to the temporal structure of focal movement and the postural strategy to successfully perform -constrained- whole-body reaching movements in microgravity. These immediate reorganizations are likely achieved by rapidly taking into account the absence of gravity in motor preparation and execution (presumably from cues about body limbs unweighting). Specifically, when compared to normogravity, the arm deceleration phase substantially increased. Furthermore, greater whole-body forward displacements due to smaller trunk flexions occurred when reaching far targets in microgravity. Remarkably, these changes of focal kinematics and postural strategy appear close to those previously reported when participants performed the same task underwater with neutral buoyancy applied to body limbs. Overall, these novel findings reveal that humans are able to maintain the performance of functional goal-directed whole-body actions in weightlessness by successfully managing spatiotemporal constraints of execution in this unusual environment.
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Affiliation(s)
| | | | - Frank Buloup
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | - Marie-Laure Mille
- Aix Marseille Univ, CNRS, ISM, Marseille, France.,UFR STAPS, Université de Toulon, La Garde, France.,Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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27
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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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Wang W, Dounskaia N. Neural control of arm movements reveals a tendency to use gravity to simplify joint coordination rather than to decrease muscle effort. Neuroscience 2016; 339:418-432. [DOI: 10.1016/j.neuroscience.2016.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/03/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
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Yamamoto S, Shiraki Y, Uehara S, Kushiro K. Motor control of downward object-transport movements with precision grip by object weight. Somatosens Mot Res 2016; 33:130-6. [PMID: 27430351 DOI: 10.1080/08990220.2016.1203304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In the present study, we investigated the kinematics of object-transport movement in a downward direction using a precision grip, to elucidate how the central nervous system (CNS) takes into account object weight when making the movement, even when participants are unable to recognize the weight until they grasp the object. We found that the kinematics during transport movement were significantly changed by the object weight, even when the weight was unrecognized visually, suggesting that the CNS controls object-transport movement in a downward direction according to object weight, regardless of the visual recognizability of the weight.
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Affiliation(s)
- Shinji Yamamoto
- a School of Health and Sport Sciences , Osaka University of Health and Sport Sciences , Osaka , Japan
| | - Yoshihide Shiraki
- b Graduate School of Human and Environmental Studies , Kyoto University , Kyoto , Japan
| | - Shintaro Uehara
- c Center for Information and Neural Networks , National Institute of Information and Communications Technology , Osaka , Japan ;,d The Japan Society for the Promotion of Science , Tokyo , Japan
| | - Keisuke Kushiro
- b Graduate School of Human and Environmental Studies , Kyoto University , Kyoto , Japan
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30
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Rousseau C, Papaxanthis C, Gaveau J, Pozzo T, White O. Initial information prior to movement onset influences kinematics of upward arm pointing movements. J Neurophysiol 2016; 116:1673-1683. [PMID: 27486106 DOI: 10.1152/jn.00616.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 07/11/2016] [Indexed: 11/22/2022] Open
Abstract
To elaborate a motor plan and perform online control in the gravity field, the brain relies on priors and multisensory integration of information. In particular, afferent and efferent inputs related to the initial state are thought to convey sensorimotor information to plan the upcoming action. Yet it is still unclear to what extent these cues impact motor planning. Here we examined the role of initial information on the planning and execution of arm movements. Participants performed upward arm movements around the shoulder at three speeds and in two arm conditions. In the first condition, the arm was outstretched horizontally and required a significant muscular command to compensate for the gravitational shoulder torque before movement onset. In contrast, in the second condition the arm was passively maintained in the same position with a cushioned support and did not require any muscle contraction before movement execution. We quantified differences in motor performance by comparing shoulder velocity profiles. Previous studies showed that asymmetric velocity profiles reflect an optimal integration of the effects of gravity on upward movements. Consistent with this, we found decreased acceleration durations in both arm conditions. However, early differences in kinematic asymmetries and EMG patterns between the two conditions signaled a change of the motor plan. This different behavior carried on through trials when the arm was at rest before movement onset and may reveal a distinct motor strategy chosen in the context of uncertainty. Altogether, we suggest that the information available online must be complemented by accurate initial information.
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Affiliation(s)
- Célia Rousseau
- Université de Bourgogne Franche-Comté (UBFC), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; Institut National de Santé et de Recherche Médicale (INSERM U1093), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; and
| | - Charalambos Papaxanthis
- Université de Bourgogne Franche-Comté (UBFC), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; Institut National de Santé et de Recherche Médicale (INSERM U1093), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; and
| | - Jérémie Gaveau
- Université de Bourgogne Franche-Comté (UBFC), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; Institut National de Santé et de Recherche Médicale (INSERM U1093), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; and
| | - Thierry Pozzo
- Université de Bourgogne Franche-Comté (UBFC), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; Institut National de Santé et de Recherche Médicale (INSERM U1093), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; and Institut Universitaire de France (IUF), Paris, France
| | - Olivier White
- Université de Bourgogne Franche-Comté (UBFC), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; Institut National de Santé et de Recherche Médicale (INSERM U1093), Cognition Action et Plasticité Sensorimotrice (CAPS) UMR1093, Dijon, France; and
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31
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Macaluso T, Bourdin C, Buloup F, Mille ML, Sainton P, Sarlegna FR, Taillebot V, Vercher JL, Weiss P, Bringoux L. Kinematic features of whole-body reaching movements underwater: Neutral buoyancy effects. Neuroscience 2016; 327:125-35. [PMID: 27095713 DOI: 10.1016/j.neuroscience.2016.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 11/25/2022]
Abstract
Astronauts' training is conventionally performed in a pool to reproduce weightlessness by exploiting buoyancy which is supposed to reduce the impact of gravity on the body. However, this training method has not been scientifically validated yet, and requires first to study the effects of underwater exposure on motor behavior. We examined the influence of neutral buoyancy on kinematic features of whole-body reaching underwater and compared them with those produced on land. Eight professional divers were asked to perform arm reaching movements toward visual targets while standing. Targets were presented either close or far from the subjects (requiring in the latter case an additional whole-body displacement). Reaching movements were performed on land or underwater in two different contexts of buoyancy. The divers either wore a diving suit only with neutral buoyancy applied to their center of mass or were additionally equipped with a submersible simulated space suit with neutral buoyancy applied to their body limbs. Results showed that underwater exposure impacted basic movement features, especially movement speed which was reduced. However, movement kinematics also differed according to the way buoyancy was exerted on the whole-body. When neutral buoyancy was applied to the center of mass only, some focal and postural components of whole-body reaching remained close to land observations, notably when considering the relative deceleration duration of arm elevation and concomitant forward trunk bending when reaching the far target. On the contrary, when neutral buoyancy was exerted on body segments, movement kinematics were close to those reported in weightlessness, as reflected by the arm deceleration phase and the whole-body forward displacement when reaching the far target. These results suggest that astronauts could benefit from the application of neutral buoyancy across the whole-body segments to optimize underwater training and acquire specific motor skills which will be used in space.
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Affiliation(s)
- T Macaluso
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - C Bourdin
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - F Buloup
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - M-L Mille
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France; Université de Toulon, 83957 La Garde, France; Department of Physical Therapy and Human Movement Sciences, Northwestern University Medical School, Chicago, IL 60611, United States
| | - P Sainton
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - F R Sarlegna
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - V Taillebot
- COMEX S.A., 36 Bvd des Océans, 13009 Marseille, France
| | - J-L Vercher
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France
| | - P Weiss
- COMEX S.A., 36 Bvd des Océans, 13009 Marseille, France
| | - L Bringoux
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille Cedex 09, France.
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How do visual and postural cues combine for self-tilt perception during slow pitch rotations? Acta Psychol (Amst) 2014; 153:51-9. [PMID: 25299446 DOI: 10.1016/j.actpsy.2014.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 09/10/2014] [Accepted: 09/17/2014] [Indexed: 11/23/2022] Open
Abstract
Self-orientation perception relies on the integration of multiple sensory inputs which convey spatially-related visual and postural cues. In the present study, an experimental set-up was used to tilt the body and/or the visual scene to investigate how these postural and visual cues are integrated for self-tilt perception (the subjective sensation of being tilted). Participants were required to repeatedly rate a confidence level for self-tilt perception during slow (0.05°·s(-1)) body and/or visual scene pitch tilts up to 19° relative to vertical. Concurrently, subjects also had to perform arm reaching movements toward a body-fixed target at certain specific angles of tilt. While performance of a concurrent motor task did not influence the main perceptual task, self-tilt detection did vary according to the visuo-postural stimuli. Slow forward or backward tilts of the visual scene alone did not induce a marked sensation of self-tilt contrary to actual body tilt. However, combined body and visual scene tilt influenced self-tilt perception more strongly, although this effect was dependent on the direction of visual scene tilt: only a forward visual scene tilt combined with a forward body tilt facilitated self-tilt detection. In such a case, visual scene tilt did not seem to induce vection but rather may have produced a deviation of the perceived orientation of the longitudinal body axis in the forward direction, which may have lowered the self-tilt detection threshold during actual forward body tilt.
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Saradjian AH, Paleressompoulle D, Louber D, Coyle T, Blouin J, Mouchnino L. Do gravity-related sensory information enable the enhancement of cortical proprioceptive inputs when planning a step in microgravity? PLoS One 2014; 9:e108636. [PMID: 25259838 PMCID: PMC4178185 DOI: 10.1371/journal.pone.0108636] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/29/2014] [Indexed: 11/18/2022] Open
Abstract
We recently found that the cortical response to proprioceptive stimulation was greater when participants were planning a step than when they stood still, and that this sensory facilitation was suppressed in microgravity. The aim of the present study was to test whether the absence of gravity-related sensory afferents during movement planning in microgravity prevented the proprioceptive cortical processing to be enhanced. We reestablished a reference frame in microgravity by providing and translating a horizontal support on which the participants were standing and verified whether this procedure restored the proprioceptive facilitation. The slight translation of the base of support (lateral direction), which occurred prior to step initiation, stimulated at least cutaneous and vestibular receptors. The sensitivity to proprioceptive stimulation was assessed by measuring the amplitude of the cortical somatosensory-evoked potential (SEP, over the Cz electrode) following the vibration of the leg muscle. The vibration lasted 1 s and the participants were asked to either initiate a step at the vibration offset or to remain still. We found that the early SEP (90-160 ms) was smaller when the platform was translated than when it remained stationary, revealing the existence of an interference phenomenon (i.e., when proprioceptive stimulation is preceded by the stimulation of different sensory modalities evoked by the platform translation). By contrast, the late SEP (550 ms post proprioceptive stimulation onset) was greater when the translation preceded the vibration compared to a condition without pre-stimulation (i.e., no translation). This suggests that restoring a body reference system which is impaired in microgravity allowed a greater proprioceptive cortical processing. Importantly, however, the late SEP was similarly increased when participants either produced a step or remained still. We propose that the absence of step-induced facilitation of proprioceptive cortical processing results from a decreased weight of proprioception in the absence of balance constraints in microgravity.
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Affiliation(s)
- Anahid H. Saradjian
- Aix-Marseille Université, CNRS, Laboratoire Neurosciences Cognitives UMR 7291, Marseille, France
| | - Dany Paleressompoulle
- Fédération de Recherche 3C Comportement-Cerveau-Cognition, CNRS -Aix-Marseille University, Marseille, France
| | - Didier Louber
- Aix-Marseille Université, CNRS, Laboratoire Neurosciences Cognitives UMR 7291, Marseille, France
| | - Thelma Coyle
- Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement, UMR 7287, Marseille, France
| | - Jean Blouin
- Aix-Marseille Université, CNRS, Laboratoire Neurosciences Cognitives UMR 7291, Marseille, France
| | - Laurence Mouchnino
- Aix-Marseille Université, CNRS, Laboratoire Neurosciences Cognitives UMR 7291, Marseille, France
- * E-mail:
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Combined influence of visual scene and body tilt on arm pointing movements: gravity matters! PLoS One 2014; 9:e99866. [PMID: 24925371 PMCID: PMC4055731 DOI: 10.1371/journal.pone.0099866] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 05/19/2014] [Indexed: 11/19/2022] Open
Abstract
Performing accurate actions such as goal-directed arm movements requires taking into account visual and body orientation cues to localize the target in space and produce appropriate reaching motor commands. We experimentally tilted the body and/or the visual scene to investigate how visual and body orientation cues are combined for the control of unseen arm movements. Subjects were asked to point toward a visual target using an upward movement during slow body and/or visual scene tilts. When the scene was tilted, final pointing errors varied as a function of the direction of the scene tilt (forward or backward). Actual forward body tilt resulted in systematic target undershoots, suggesting that the brain may have overcompensated for the biomechanical movement facilitation arising from body tilt. Combined body and visual scene tilts also affected final pointing errors according to the orientation of the visual scene. The data were further analysed using either a body-centered or a gravity-centered reference frame to encode visual scene orientation with simple additive models (i.e., ‘combined’ tilts equal to the sum of ‘single’ tilts). We found that the body-centered model could account only for some of the data regarding kinematic parameters and final errors. In contrast, the gravity-centered modeling in which the body and visual scene orientations were referred to vertical could explain all of these data. Therefore, our findings suggest that the brain uses gravity, thanks to its invariant properties, as a reference for the combination of visual and non-visual cues.
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Gaveau J, Berret B, Demougeot L, Fadiga L, Pozzo T, Papaxanthis C. Energy-related optimal control accounts for gravitational load: comparing shoulder, elbow, and wrist rotations. J Neurophysiol 2013; 111:4-16. [PMID: 24133223 DOI: 10.1152/jn.01029.2012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We permanently deal with gravity force. Experimental evidences revealed that moving against gravity strongly differs from moving along the gravity vector. This directional asymmetry has been attributed to an optimal planning process that optimizes gravity force effects to minimize energy. Yet, only few studies have considered the case of vertical movements in the context of optimal control. What kind of cost is better suited to explain kinematic patterns in the vertical plane? Here, we aimed to understand further how the central nervous system (CNS) plans and controls vertical arm movements. Our reasoning was the following: if the CNS optimizes gravity mechanical effects on the moving limbs, kinematic patterns should change according to the direction and the magnitude of the gravity torque being encountered in the motion. Ten subjects carried out single-joint movements, i.e., rotation around the shoulder (whole arm), elbow (forearm), and wrist (hand) joints, in the vertical plane. Joint kinematics were analyzed and compared with various theoretical optimal model predictions (minimum absolute work-jerk, jerk, torque change, and variance). We found both direction-dependent and joint-dependent variations in several kinematic parameters. Notably, directional asymmetries decreased according to a proximodistal gradient. Numerical simulations revealed that our experimental findings could be attributed to an optimal motor planning (minimum absolute work-jerk) that integrates the direction and the magnitude of gravity torque and minimizes the absolute work of forces (energy-related cost) around each joint. Present results support the general idea that the CNS implements optimal solutions according to the dynamic context of the action.
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Saradjian AH, Tremblay L, Perrier J, Blouin J, Mouchnino L. Cortical facilitation of proprioceptive inputs related to gravitational balance constraints during step preparation. J Neurophysiol 2013; 110:397-407. [PMID: 23576699 DOI: 10.1152/jn.00905.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several studies have shown that the transmission of afferent inputs from the periphery to the somatosensory cortex is attenuated during the preparation of voluntary movements. In the present study, we tested whether sensory attenuation is also observed during the preparation of a voluntary step. It would appear dysfunctional to suppress somatosensory information, which is considered to be of the utmost importance for gait preparation. In this context, we predict that the somatosensory information is facilitated during gait preparation. To test this prediction, we recorded cortical somatosensory potentials (SEPs) evoked by bilateral lower limb vibration (i.e., proprioceptive inputs) during the preparation phase of a voluntary right-foot stepping movement (i.e., stepping condition). The subjects were also asked to remain still during and after the vibration as a control condition (i.e., static condition). The amplitude and timing of the early arrival of afferent inflow to the somatosensory cortices (i.e., P1-N1) were not significantly different between the static and stepping conditions. However, a large sustained negativity (i.e., late SEP) developed after the P1-N1 component, which was larger when subjects were preparing a step compared with standing. To determine whether this facilitation of proprioceptive inputs was related to gravitational equilibrium constraints, we performed the same experiment in microgravity. In the absence of equilibrium constraints, both the P1-N1 and late SEPs did not significantly differ between the static and stepping conditions. These observations provide neurophysiological evidence that the brain exerts a dynamic control over the transmission of the afferent signal according to their current relevance during movement preparation.
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Affiliation(s)
- Anahid H Saradjian
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Laboratoire Neurosciences Cognitives UMR 7291, Marseille, France
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