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Bruening GW, Courter RJ, Sukumar S, O’Brien MK, Ahmed AA. Disentangling the effects of metabolic cost and accuracy on movement speed. PLoS Comput Biol 2024; 20:e1012169. [PMID: 38820571 PMCID: PMC11168626 DOI: 10.1371/journal.pcbi.1012169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 06/12/2024] [Accepted: 05/14/2024] [Indexed: 06/02/2024] Open
Abstract
On any given day, we make countless reaching movements to objects around us. While such ubiquity may suggest uniformity, each movement's speed is unique-why is this? Reach speed is known to be influenced by accuracy; we slow down to sustain high accuracy. However, in other forms of movement like walking or running, metabolic cost is often the primary determinant of movement speed. Here we bridge this gap and ask: how do metabolic cost and accuracy interact to determine speed of reaching movements? First, we systematically measure the effect of increasing mass on the metabolic cost of reaching across a range of movement speeds. Next, in a sequence of three experiments, we examine how added mass affects preferred reaching speed across changing accuracy requirements. We find that, while added mass consistently increases metabolic cost thereby leading to slower metabolically optimal movement speeds, self-selected reach speeds are slower than those predicted by an optimization of metabolic cost alone. We then demonstrate how a single model that considers both accuracy and metabolic costs can explain preferred movement speeds. Together, our findings provide a unifying framework to illuminate the combined effects of metabolic cost and accuracy on movement speed and highlight the integral role metabolic cost plays in determining reach speed.
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Affiliation(s)
- Garrick W. Bruening
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado, United States of America
| | - Robert J. Courter
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado, United States of America
| | - Shruthi Sukumar
- Department of Computer Science, University of Colorado, Boulder, Colorado, United States of America
| | - Megan K. O’Brien
- Shirley Ryan Ability Lab, Northwestern University, Chicago, Illinois, United States of America
| | - Alaa A. Ahmed
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado, United States of America
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, United States of America
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2
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Kalidindi HT, Crevecoeur F. Human reaching control in dynamic environments. Curr Opin Neurobiol 2023; 83:102810. [PMID: 37950956 DOI: 10.1016/j.conb.2023.102810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 10/09/2023] [Accepted: 10/19/2023] [Indexed: 11/13/2023]
Abstract
Closed-loop models of movement control have attracted growing interest in how the nervous system transforms sensory information into motor commands, and several brain structures have been identified as neural substrates for these computational operations. Recently, several studies have focused on how these models need to be updated when environmental parameters change. Current evidence suggests that when the task changes, rapid control updates enable flexible modifications of current actions and online decisions. At the same time, when movement dynamics change, humans use different strategies based on a combination of adaptation and modulation of controller sensitivity to exogenous perturbations (robust control). This review proposes a unified framework to capture these results based on online estimation of model parameters with dynamic updates in control. The reviewed studies also identify the time scales of associated behavioral mechanisms to guide future research on the neural basis of movement control.
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Affiliation(s)
- Hari T Kalidindi
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, University of Louvain (UCLouvain), Belgium; Institute of Neuroscience, UCLouvain, Belgium
| | - Frédéric Crevecoeur
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, University of Louvain (UCLouvain), Belgium; Institute of Neuroscience, UCLouvain, Belgium.
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3
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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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4
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De Comite A, Lefèvre P, Crevecoeur F. Continuous evaluation of cost-to-go for flexible reaching control and online decisions. PLoS Comput Biol 2023; 19:e1011493. [PMID: 37756355 PMCID: PMC10561875 DOI: 10.1371/journal.pcbi.1011493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 10/09/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Humans consider the parameters linked to movement goal during reaching to adjust their control strategy online. Indeed, rapid changes in target structure or disturbances interfering with their initial plan elicit rapid changes in behavior. Here, we hypothesize that these changes could result from the continuous use of a decision variable combining motor and cognitive components. We combine an optimal feedback controller with a real-time evaluation of the expected cost-to-go, which considers target- and movement-related costs, in a common theoretical framework. This model reproduces human behaviors in presence of changes in the target structure occurring during movement and of online decisions to flexibly change target following external perturbations. It also predicts that the time taken to decide to select a novel goal after a perturbation depends on the amplitude of the disturbance and on the rewards of the different options, which is a direct result of the continuous monitoring of the cost-to-go. We show that this result was present in our previously collected dataset. Together our developments point towards a continuous evaluation of the cost-to-go during reaching to update control online and make efficient decisions about movement goal.
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Affiliation(s)
- Antoine De Comite
- Institute of Neuroscience, UCLouvain, Louvain-la-Neuve, Belgium
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, UCLouvain, Louvain-la-Neuve, Belgium
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Philippe Lefèvre
- Institute of Neuroscience, UCLouvain, Louvain-la-Neuve, Belgium
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, UCLouvain, Louvain-la-Neuve, Belgium
| | - Frédéric Crevecoeur
- Institute of Neuroscience, UCLouvain, Louvain-la-Neuve, Belgium
- Institute of Information and Communication Technologies, Electronics and Applied Mathematics, UCLouvain, Louvain-la-Neuve, Belgium
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5
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Labaune O, Berret B. The vigor law as a kinematic invariant at work in perceptual-cognitive processes: Comment on "Motor invariants in action execution and perception" by Francesco Torricelli et al. Phys Life Rev 2023; 46:1-4. [PMID: 37210934 DOI: 10.1016/j.plrev.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/23/2023]
Affiliation(s)
- Ombeline Labaune
- Laboratory of Visuomotor Control and Gravitational Physiology, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy
| | - Bastien Berret
- CIAMS, Université Paris-Saclay, Orsay, France; CIAMS, Université d'Orléans, Orléans, France.
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Pierrieau E, Berret B, Lepage JF, Bernier PM. From Motivation to Action: Action Cost Better Predicts Changes in Premovement Beta-Band Activity than Speed. J Neurosci 2023; 43:5264-5275. [PMID: 37339875 PMCID: PMC10342222 DOI: 10.1523/jneurosci.0213-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 05/03/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023] Open
Abstract
Although premovement beta-band event-related desynchronization (β-ERD; 13-30 Hz) from sensorimotor regions is modulated by movement speed, current evidence does not support a strict monotonic association between the two. Given that β-ERD is thought to increase information encoding capacity, we tested the hypothesis that it might be related to the expected neurocomputational cost of movement, here referred to as action cost. Critically, action cost is greater both for slow and fast movements compared with a medium or "preferred" speed. Thirty-one right-handed participants performed a speed-controlled reaching task while recording their EEG. Results revealed potent modulations of beta power as a function of speed, with β-ERD being significantly greater both for movements performed at high and low speeds compared with medium speed. Interestingly, medium-speed movements were more often chosen by participants than low-speed and high-speed movements, suggesting that they were evaluated as less costly. In line with this, modeling of action cost revealed a pattern of modulation across speed conditions that strikingly resembled the one found for β-ERD. Indeed, linear mixed models showed that estimated action cost predicted variations of β-ERD significantly better than speed. This relationship with action cost was specific to beta power, as it was not found when averaging activity in the mu band (8-12 Hz) and gamma band (31-49 Hz) bands. These results demonstrate that increasing β-ERD may not merely speed up movements, but instead facilitate the preparation of high-speed and low-speed movements through the allocation of additional neural resources, thereby enabling flexible motor control.SIGNIFICANCE STATEMENT Heightened beta activity has been associated with movement slowing in Parkinson's disease, and modulations of beta activity are commonly used to decode movement parameters in brain-computer interfaces. Here we show that premovement beta activity is better explained by the neurocomputational cost of the action rather than its speed. Instead of being interpreted as a mere reflection of changes in movement speed, premovement changes in beta activity might therefore be used to infer the amount of neural resources that are allocated for motor planning.
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Affiliation(s)
- Emeline Pierrieau
- Programme de Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Bastien Berret
- CIAMS (Complexité, Innovation, Activités, Motrices, et Sportives), Université Paris-Saclay, 91405 Orsay, France
- CIAMS (Complexité, Innovation, Activités, Motrices, et Sportives), Université d'Orléans, 45067 Orléans, France
- Institut Universitaire de France, 75231 Paris, France
| | - Jean-François Lepage
- Programme de Physiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
- Département de Pédiatrie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Pierre-Michel Bernier
- Département de Kinanthropologie, Faculté des Sciences de l'Activité Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
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Verdel D, Sahm G, Bruneau O, Berret B, Vignais N. A Trade-Off between Complexity and Interaction Quality for Upper Limb Exoskeleton Interfaces. SENSORS (BASEL, SWITZERLAND) 2023; 23:4122. [PMID: 37112463 PMCID: PMC10142870 DOI: 10.3390/s23084122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/14/2023] [Accepted: 04/18/2023] [Indexed: 06/19/2023]
Abstract
Exoskeletons are among the most promising devices dedicated to assisting human movement during reeducation protocols and preventing musculoskeletal disorders at work. However, their potential is currently limited, partially because of a fundamental contradiction impacting their design. Indeed, increasing the interaction quality often requires the inclusion of passive degrees of freedom in the design of human-exoskeleton interfaces, which increases the exoskeleton's inertia and complexity. Thus, its control also becomes more complex, and unwanted interaction efforts can become important. In the present paper, we investigate the influence of two passive rotations in the forearm interface on sagittal plane reaching movements while keeping the arm interface unchanged (i.e., without passive degrees of freedom). Such a proposal represents a possible compromise between conflicting design constraints. The in-depth investigations carried out here in terms of interaction efforts, kinematics, electromyographic signals, and subjective feedback of participants all underscored the benefits of such a design. Therefore, the proposed compromise appears to be suitable for rehabilitation sessions, specific tasks at work, and future investigations into human movement using exoskeletons.
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Affiliation(s)
- Dorian Verdel
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, 45100 Orléans, France
- LURPA, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Guillaume Sahm
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, 45100 Orléans, France
| | - Olivier Bruneau
- LURPA, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Bastien Berret
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, 45100 Orléans, France
| | - Nicolas Vignais
- Université Paris-Saclay, CIAMS, 91405 Orsay, France
- CIAMS, Université d’Orléans, 45100 Orléans, France
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8
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Korbisch CC, Apuan DR, Shadmehr R, Ahmed AA. Saccade vigor reflects the rise of decision variables during deliberation. Curr Biol 2022; 32:5374-5381.e4. [PMID: 36413989 PMCID: PMC9795813 DOI: 10.1016/j.cub.2022.10.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 08/12/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022]
Abstract
During deliberation, as we quietly consider our options, the neural activities representing the decision variables that reflect the goodness of each option rise in various regions of the cerebral cortex.1,2,3,4,5,6,7 If the options are depicted visually, we make saccades, focusing gaze on each option. Do the kinematics of these saccades reflect the state of the decision variables? To test this idea, we engaged human participants in a decision-making task in which they considered two effortful options that required walking across various distances and inclines. As they deliberated, they made saccades between the symbolic representations of their options. These deliberation period saccades had no bearing on the effort they would later expend, yet saccade velocities increased gradually and differentially: the rate of rise was faster for saccades toward the option that they later indicated as their choice. Indeed, the rate of rise encoded the difference in the subjective value of the two options. Importantly, the participants did not reveal their choice at the conclusion of deliberation, but rather waited during a delay period, and finally expressed their choice by making another saccade. Remarkably, vigor for this saccade dropped to baseline and no longer encoded subjective value. Thus, saccade vigor appeared to provide a real-time window to the otherwise hidden process of option evaluation during deliberation.
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Affiliation(s)
- Colin C Korbisch
- Mechanical Engineering and Biomedical Engineering, Neuromechanics Laboratory, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Daniel R Apuan
- Mechanical Engineering and Biomedical Engineering, Neuromechanics Laboratory, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Reza Shadmehr
- Department of Biomedical Engineering, Laboratory for Computational Motor Control, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Alaa A Ahmed
- Mechanical Engineering and Biomedical Engineering, Neuromechanics Laboratory, University of Colorado Boulder, Boulder, CO 80309, USA.
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