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de Vries S, Huys R, Zanone PG. Keeping your eye on the target: eye-hand coordination in a repetitive Fitts' task. Exp Brain Res 2018; 236:3181-3190. [PMID: 30182273 DOI: 10.1007/s00221-018-5369-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/29/2018] [Indexed: 11/28/2022]
Abstract
In a cyclical Fitts' task, hand movements transition from continuous to discrete movements when the Index of Difficulty (ID) increases. Moreover, at high ID (small target), the eyes saccade to and subsequently fixate the targets at every movement, while at low ID (large target) intermittent monitoring is used. By hypothesis, the (periodic) gaze shifts are abandoned for movement times shorter than about 0.350 s due to systemic constraints (i.e., a refractory period and intrinsic latency). If so, the transition in eye and hand movements is independent. To investigate these issues, the present study examined the effects of changing ID via the targets' width or distance as well as hysteresis in eye-hand coordination. To this aim, 14 participants performed a cyclical Fitts' task while their hand and eye movements were recorded simultaneously. The results show that the transition in eye-hand synchronization (at 2.87 bit; 0.25 s) and in hand dynamics (at 4.85 bit; 0.81 s) neither co-occurred nor correlated. Some small width vs. distance dissociations and hysteresis effects were found, but they disappeared when eye-hand synchronization was viewed as a function of movement time rather than ID. This confirms that a minimal between-saccade time is the limiting factor in eye-hand synchronization. Additionally, the timing between the start of the hand movement and the saccade appeared to be relatively constant (at 0.15 s) and independent of movement time, implying a constant delay that should be implemented in a dynamical model of eye-hand coordination.
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Affiliation(s)
- S de Vries
- Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, P.O. Box 196, 9700 AD, Groningen, The Netherlands.
| | - R Huys
- Université de Toulouse, UMR 5549 CERCO (Centre de Recherche Cerveau et Cognition), UPS, CNRS, Pavillon Baudot CHU Purpan, 31052, Toulouse, France
| | - P G Zanone
- Université de Toulouse, UMR 5549 CERCO (Centre de Recherche Cerveau et Cognition), UPS, CNRS, Pavillon Baudot CHU Purpan, 31052, Toulouse, France
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2
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Effects of wrist tendon vibration and eye movements on manual aiming. Exp Brain Res 2018; 236:847-857. [PMID: 29353311 DOI: 10.1007/s00221-018-5180-z] [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] [Received: 07/18/2017] [Accepted: 01/12/2018] [Indexed: 12/19/2022]
Abstract
In the present study, we investigated whether visual information mediates a proprioceptive illusion effect induced by muscle tendon vibration in manual aiming. Visual information was gradually degraded from a situation in which the targets were present and participants (n = 20; 22.3 ± 2.7 years) were permitted to make saccadic eye movements to designated target positions, to a condition in which the targets were not visible and participants were required to perform cyclical aiming while fixating a point between the two target positions. Local tendon vibration applied to the right wrist extensor muscles induced an illusory reduction of 15% in hand movement amplitude. This effect was greater in the fixation than in the saccade condition. Both anticipatory control and proprioceptive feedback are proposed to contribute to the observed effects. The primary saccade amplitude was also reduced by almost 4% when muscle tendon vibration was locally applied to the wrist. These results confirm a tight link between eye movements and manual perception and action. Moreover, the impact of the proprioceptive illusion on the ocular system indicates that the interaction between systems is bidirectional.
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3
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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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4
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The action-specific effect of execution on imagination of reciprocal aiming movements. Hum Mov Sci 2017; 54:51-62. [PMID: 28395146 DOI: 10.1016/j.humov.2017.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 02/02/2023]
Abstract
Past research has shown that the movement times of imagined aiming movements were more similar to actual movement times after the individual has experienced executing the movements. The purpose of the present study was to determine if experience with a set of movements altered the imagination of movements that were not experienced. Participants imagined a series of reciprocal aiming movements in different movement difficulty contexts (created by altering target width and movement amplitude) before and after actually executing a series of aiming movements. The range of difficulties of the imagined movements included difficulty contexts that were within (Experiment 1) or outside (Experiment 2) the range of difficulty experienced during execution. It was found that imagined movement times of movements within the range of movement difficulties experienced were more consistent with Fitts' Law after movement experience, whereas imagination of more difficult movements was not altered by experience. It is suggested that execution did not enhance imagination of more difficult movements because the relative contributions of motor planning and control to the more difficult movements were different from those in the experienced movements. Thus, the enhancement of imagination through experience might only occur when mechanisms underlying the executed and imagined movements are similar.
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5
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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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6
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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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Helsen WF, Van Halewyck F, Levin O, Boisgontier MP, Lavrysen A, Elliott D. Manual aiming in healthy aging: does proprioceptive acuity make the difference? AGE (DORDRECHT, NETHERLANDS) 2016; 38:45. [PMID: 27044301 PMCID: PMC5005912 DOI: 10.1007/s11357-016-9908-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/24/2016] [Indexed: 06/05/2023]
Abstract
The present study examines whether non-active older adults are more dependent on visual information when executing aiming movements and whether age-related declines in proprioception play a mediating role herein. Young (N = 40) and older adults (N = 38) were divided into physically active and non-active subgroups based on self-reported sports participation levels. In experiment 1, participants executed wrist-aiming movements with and without visual feedback. In experiment 2, passive proprioceptive acuity was assessed using wrist motion detection and position matching tests. Results showed similar aiming accuracy across age groups both with and without visual feedback, but older adults exhibited longer movement times, prolonged homing-in phase, and made more corrective submovements. Passive proprioceptive acuity was significantly affected by physical activity level and age, with participants in the active group scoring better than their non-active peers. However, these declines did not predict performance changes on the aiming task. Taken together, our observations suggest that decline in proprioceptive acuity did not predict performance changes on the aiming task and older adults were able to compensate for their decreased motion and position sense when allowed sufficient time. In line with these observations, we proposed that older adults are able to compensate for their decline in proprioception by increasing their reliance on predictive models.
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Affiliation(s)
- Werner F Helsen
- Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Florian Van Halewyck
- Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Oron Levin
- Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
| | - Matthieu P Boisgontier
- Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Ann Lavrysen
- Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium
| | - Digby Elliott
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
- Department of Kinesiology, McMaster University, 1280 Main Street West Ivor Wynne Centre Hamilton, Ontorio, L8S 4K1, Canada
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8
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Van Halewyck F, Lavrysen A, Levin O, Boisgontier MP, Elliott D, Helsen WF. Both age and physical activity level impact on eye-hand coordination. Hum Mov Sci 2014; 36:80-96. [PMID: 24964357 DOI: 10.1016/j.humov.2014.05.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 05/05/2014] [Accepted: 05/19/2014] [Indexed: 12/17/2022]
Abstract
Aging impacts on our ability to perform goal-directed aiming movements. Older adults generally make slower and shorter initial impulses towards the end target, and therefore require more time for corrections in the final movement stage. Recent studies however suggest that a physically active lifestyle may attenuate these age-related changes. Also, it remains unclear whether eye-movement control exhibits a similar pattern of adaptation in older adults. Therefore, the first aim of this study was to describe how age and physical activity level impact eye-hand coordination during discrete manual aiming. Young and older participants were divided into physically active and sedentary subgroups, and performed discrete aiming movements while hand and eye movements were recorded. Secondly, to determine whether older adults depend more on vision during aiming, the task was repeated without visual feedback. The results revealed that the typical age-related hand movement adaptations were not only observed in older, but also in sedentary young participants. Older and sedentary young participants also spent more hand movement time after the eyes fixated the end target. This finding does not necessarily reflect an augmented reliance on vision, as all groups showed similar aiming errors when visual feedback was removed. In conclusion, both age and physical activity level clearly impacted eye-hand coordination during discrete manual aiming. This adapted coordination pattern seems to be caused by other factors than an increased reliance on vision.
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Affiliation(s)
- Florian Van Halewyck
- KU Leuven, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Belgium
| | - Ann Lavrysen
- KU Leuven, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Belgium
| | - Oron Levin
- KU Leuven, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Belgium
| | - Matthieu P Boisgontier
- KU Leuven, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Belgium
| | - Digby Elliott
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK
| | - Werner F Helsen
- KU Leuven, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Belgium.
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Kim KH, Gillespie RB, Martin BJ. Negotiated control between the manual and visual systems for visually guided hand reaching movements. J Neuroeng Rehabil 2014; 11:102. [PMID: 24920401 PMCID: PMC4082178 DOI: 10.1186/1743-0003-11-102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 05/22/2014] [Indexed: 12/04/2022] Open
Abstract
Background Control of reaching movements for manual work, vehicle operation, or interactions with manual interfaces requires concurrent gaze control for visual guidance of the hand. We hypothesize that reaching movements are based on negotiated strategies to resolve possible conflicting demands placed on body segments shared by the visual (gaze) and manual (hand) control systems. Further, we hypothesize that a multiplicity of possible spatial configurations (redundancy) in a movement system enables a resolution of conflicting demands that does not require sacrificing the goals of the two systems. Methods The simultaneous control of manual reach and gaze during seated reaching movements was simulated by solving an inverse kinematics model wherein joint trajectories were estimated from a set of recorded hand and head movements. A secondary objective function, termed negotiation function, was introduced to describe a means for the manual reach and gaze directing systems to balance independent goals against (possibly competing) demands for shared resources, namely the torso movement. For both systems, the trade-off may be resolved without sacrificing goal achievement by taking advantage of redundant degrees of freedom. Estimated joint trajectories were then compared to joint movement recordings from ten participants. Joint angles were predicted with and without the negotiation function in place, and model accuracy was determined using the root-mean-square errors (RMSEs) and differences between estimated and recorded joint angles. Results The prediction accuracy was generally improved when negotiation was included: the negotiated control reduced RMSE by 16% and 30% on average when compared to the systems with only manual or visual control, respectively. Furthermore, the RMSE in the negotiated control system tended to improve with torso movement amplitude. Conclusions The proposed model describes how multiple systems cooperate to perform goal-directed human movements when those movements draw upon shared resources. Allocation of shared resources can be undertaken by a negotiation process that is aware of redundancies and the existence of multiple solutions within the individual systems.
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Affiliation(s)
| | | | - Bernard J Martin
- Department of Industrial and Operations Engineering, The University of Michigan, Address: 1205 Beal Avenue, Ann Arbor, MI 48109-2117, USA.
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10
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Kinematic property of target motion conditions gaze behavior and eye-hand synergy during manual tracking. Hum Mov Sci 2013; 32:1253-69. [PMID: 24054436 DOI: 10.1016/j.humov.2013.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 12/17/2012] [Accepted: 03/22/2013] [Indexed: 11/22/2022]
Abstract
This study investigated how frequency demand and motion feedback influenced composite ocular movements and eye-hand synergy during manual tracking. Fourteen volunteers conducted slow and fast force-tracking in which targets were displayed in either line-mode or wave-mode to guide manual tracking with target movement of direct position or velocity nature. The results showed that eye-hand synergy was a selective response of spatiotemporal coupling conditional on target rate and feedback mode. Slow and line-mode tracking exhibited stronger eye-hand coupling than fast and wave-mode tracking. Both eye movement and manual action led the target signal during fast-tracking, while the latency of ocular navigation during slow-tracking depended on the feedback mode. Slow-tracking resulted in more saccadic responses and larger pursuit gains than fast-tracking. Line-mode tracking led to larger pursuit gains but fewer and shorter gaze fixations than wave-mode tracking. During slow-tracking, incidences of saccade and gaze fixation fluctuated across a target cycle, peaking at velocity maximum and the maximal curvature of target displacement, respectively. For line-mode tracking, the incidence of smooth pursuit was phase-dependent, peaking at velocity maximum as well. Manual behavior of slow or line-mode tracking was better predicted by composite eye movements than that of fast or wave-mode tracking. In conclusion, manual tracking relied on versatile visual strategies to perceive target movements of different kinematic properties, which suggested a flexible coordinative control for the ocular and manual sensorimotor systems.
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11
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Germain-Robitaille M, Terrier R, Forestier N, Teasdale N. Hand–head coordination changes from discrete to reciprocal hand movements for various difficulty settings. Neurosci Lett 2012; 521:1-5. [DOI: 10.1016/j.neulet.2012.04.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/09/2012] [Accepted: 04/30/2012] [Indexed: 10/28/2022]
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12
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Bringoux L, Blouin J, Coyle T, Ruget H, Mouchnino L. Effect of gravity-like torque on goal-directed arm movements in microgravity. J Neurophysiol 2012; 107:2541-8. [PMID: 22298835 DOI: 10.1152/jn.00364.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gravitational force level is well-known to influence arm motor control. Specifically, hyper- or microgravity environments drastically change pointing accuracy and kinematics, particularly during initial exposure. These modifications are thought to partly reflect impairment in arm position sense. Here we investigated whether applying normogravitational constraints at joint level during microgravity episodes of parabolic flights could restore movement accuracy equivalent to that observed on Earth. Subjects with eyes closed performed arm reaching movements toward predefined sagittal angular positions in four environment conditions: normogravity, hypergravity, microgravity, and microgravity with elastic bands attached to the arm to mimic gravity-like torque at the shoulder joint. We found that subjects overshot and undershot the target orientations in hypergravity and microgravity, respectively, relative to a normogravity baseline. Strikingly, adding gravity-like torque prior to and during movements performed in microgravity allowed subjects to be as accurate as in normogravity. In the former condition, arm movement kinematics, as notably illustrated by the relative time to peak velocity, were also unchanged relative to normogravity, whereas significant modifications were found in hyper- and microgravity. Overall, these results suggest that arm motor planning and control are tuned with respect to gravitational information issued from joint torque, which presumably enhances arm position sense and activates internal models optimally adapted to the gravitoinertial environment.
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Affiliation(s)
- L Bringoux
- CNRS-Aix-Marseille Université, UMR 7287 Institut des Sciences du Mouvement, 163, Ave. de Luminy CP 910, F13288 Marseille Cedex 9, France.
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