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Benamati A, Ricotta JM, De SD, Latash ML. Three Levels of Neural Control Contributing to Performance-stabilizing Synergies in Multi-finger Tasks. Neuroscience 2024; 551:262-275. [PMID: 38838976 DOI: 10.1016/j.neuroscience.2024.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
We tested a hypothesis on force-stabilizing synergies during four-finger accurate force production at three levels: (1) The level of the reciprocal and coactivation commands, estimated as the referent coordinate and apparent stiffness of all four fingers combined; (2) The level of individual finger forces; and (3) The level of firing of individual motor units (MU). Young, healthy participants performed accurate four-finger force production at a comfortable, non-fatiguing level under visual feedback on the total force magnitude. Mechanical reflections of the reciprocal and coactivation commands were estimated using small, smooth finger perturbations applied by the "inverse piano" device. Firing frequencies of motor units in the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) were estimated using surface recording. Principal component analysis was used to identify robust MU groups (MU-modes) with parallel changes in the firing frequency. The framework of the uncontrolled manifold hypothesis was used to compute synergy indices in the spaces of referent coordinate and apparent stiffness, finger forces, and MU-mode magnitudes. Force-stabilizing synergies were seen at all three levels. They were present in the MU-mode spaces defined for MUs in FDS, in EDC, and pooled over both muscles. No effects of hand dominance were seen. The synergy indices defined at different levels of analysis showed no correlations across the participants. The findings are interpreted within the theory of control with spatial referent coordinates for the effectors. We conclude that force stabilization gets contributions from three levels of neural control, likely associated with cortical, subcortical, and spinal circuitry.
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Affiliation(s)
- Anna Benamati
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy; Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Joseph M Ricotta
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sayan D De
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
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de Freitas PB, Freitas SMSF, Dias MS. Synergic control of the minimum toe clearance in young and older adults during foot swing on treadmill walking in different speeds. Gait Posture 2024; 111:150-155. [PMID: 38703443 DOI: 10.1016/j.gaitpost.2024.04.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 05/06/2024]
Abstract
BACKGROUND The vertical toe position at minimum toe clearance (MTC) in the swing phase is critical for walking safety. Consequently, the joints involved should be strictly controlled and coordinated to stabilize the foot at MTC. The uncontrolled manifold (UCM) hypothesis framework has been used to determine the existence of synergies that stabilize relevant performance variables during walking. However, no study investigated the presence of a multi-joint synergy stabilizing the foot position at MTC and the effects of age and walking speed on this synergy. RESEARCH QUESTIONS Is there a multi-joint synergy stabilizing MTC during treadmill walking? Does it depend on the persons' age and walking speed? METHODS Kinematic data from 23 young and 15 older adults were analyzed using the UCM approach. The participants walked on a treadmill at three speeds: slow, self-selected, and fast. The sagittal and frontal joint angles from the swing and stance legs and pelvis obliquity were used as motor elements and the vertical toe position at MTC was the performance variable. The variances in the joint space that affected (VORT, 'bad' variance) and did not affect (VUCM, 'good' variance) the toe position at MTC and the synergy index (ΔV) were computed. RESULTS The ΔV>0 was revealed for all subjects. Walking speed did not affect ΔV in older adults, whereas ΔV reduced with speed in young adults. ΔV was higher for older than for young adults at self-selected and fast speeds, owing to a lower VORT in the older group. SIGNIFICANCE The vertical toe position at MTC was stabilized by a strong multi-joint synergy. In older adults, this synergy was stronger, as they were better at limiting VORT than young adults. Reduced VORT in older adults could be caused by more constrained walking, which may be associated with anxiety due to walking on a treadmill.
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Affiliation(s)
- Paulo B de Freitas
- Interdisciplinary Graduate Program in Health Sciences, Universidade Cruzeiro do Sul, São Paulo, Rua Galvão Bueno, 868, Liberdade, São Paulo, SP 01506-000, Brazil.
| | - Sandra M S F Freitas
- Graduate Program in Physical Therapy. Universidade Cidade de São Paulo, São Paulo, Rua Cesário Galeno, 475, Tatuapé, São Paulo, SP 03071-000, Brazil.
| | - Mateus S Dias
- Interdisciplinary Graduate Program in Health Sciences, Universidade Cruzeiro do Sul, São Paulo, Rua Galvão Bueno, 868, Liberdade, São Paulo, SP 01506-000, Brazil.
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Pawłowski M, Ricotta JM, De SD, Latash ML. Force matching: motor effects that are not reported by the actor. Exp Brain Res 2024; 242:1439-1453. [PMID: 38652273 PMCID: PMC11108883 DOI: 10.1007/s00221-024-06829-4] [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: 11/06/2023] [Accepted: 04/02/2024] [Indexed: 04/25/2024]
Abstract
We explored unintentional drifts of finger forces during force production and matching task. Based on earlier studies, we predicted that force matching with the other hand would reduce or stop the force drift in instructed fingers while uninstructed (enslaved) fingers remain unaffected. Twelve young, healthy, right-handed participants performed two types of tasks with both hands (task hand and match hand). The task hand produced constant force at 20% of MVC level with the Index and Ring fingers pressing in parallel on strain gauge force sensors. The Middle finger force wasn't instructed, and its enslaved force was recorded. Visual feedback on the total force by the instructed fingers was either present throughout the trial or only during the first 5 s (no-feedback condition). The other hand matched the perceived force level of the task hand starting at either 4, 8, or 15 s from the trial initiation. No feedback was ever provided for the match hand force. After the visual feedback was removed, the task hand showed a consistent drift to lower magnitudes of total force. Contrary to our prediction, over all conditions, force matching caused a brief acceleration of force drift in the task hand, which then reached a plateau. There was no effect of matching on drifts in enslaved finger force. We interpret the force drifts within the theory of control with spatial referent coordinates as consequences of drifts in the command (referent coordinate) to the antagonist muscles. This command is not adequately incorporated into force perception.
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Affiliation(s)
- Michał Pawłowski
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Institute of Sport Science, Department of Human Motor Behavior, Academy of Physical Education in Katowice, 72A Mikołowska St, Katowice, 40-065, Poland.
| | - Joseph M Ricotta
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sayan D De
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
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Winterbottom L, Nilsen DM. Motor Learning Following Stroke: Mechanisms of Learning and Techniques to Augment Neuroplasticity. Phys Med Rehabil Clin N Am 2024; 35:277-291. [PMID: 38514218 DOI: 10.1016/j.pmr.2023.06.004] [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] [Indexed: 03/23/2024]
Abstract
Sensorimotor impairments are common after stroke requiring stroke survivors to relearn lost motor skills or acquire new ones in order to engage in daily activities. Thus, motor skill learning is a cornerstone of stroke rehabilitation. This article provides an overview of motor control and learning theories that inform stroke rehabilitation interventions, discusses principles of neuroplasticity, and provides a summary of practice conditions and techniques that can be used to augment motor learning and neuroplasticity in stroke rehabilitation.
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Affiliation(s)
- Lauren Winterbottom
- Department of Rehabilitation & Regenerative Medicine, Columbia University, 180 Fort Washington Avenue, HP1, Suite 199, New York, NY 10032, USA; Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA.
| | - Dawn M Nilsen
- Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA; Department of Rehabilitation & Regenerative Medicine, Columbia University, 617 West 168th Street, 3rd Floor, Room 305, New York, NY 10032, USA
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Majcen Rosker Z, Rosker J. Cervicocephalic kinaesthesia reveals novel subgroups of motor control impairments in patients with neck pain. Sci Rep 2024; 14:8383. [PMID: 38600120 PMCID: PMC11006834 DOI: 10.1038/s41598-024-57326-1] [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: 08/23/2023] [Accepted: 03/18/2024] [Indexed: 04/12/2024] Open
Abstract
Cervical-spine sensorimotor control is associated with chronicity and recurrence of neck pain (NP). Tests used to measure sensorimotor impairments lack consistency in studied parameters. Interpretation is often based on either a handful or numerous parameters, without considering their possible interrelation. Different aspects of motor-control could be studied with different parameters, but this has not yet been addressed. The aim of this study was to determine if different parameters of cervical position (JPE) and movement (Butterfly) sense tests represent distinct components of motor-control strategies in patients with chronic NP. Principal component analysis performed on 135 patients revealed three direction-specific (repositioning from flexion, extension or rotations) and one parameter-specific (variability of repositioning) component for JPE, two difficulty-specific (easy or medium and difficult trajectory) and one movement-specific (undershooting a target) component for Butterfly test. Here we report that these components could be related to central (neck repositioning and control of cervical movement) and peripheral sensorimotor adaptations (variability of repositioning) present in NP. New technologies allow extraction of greater number of parameters of which hand-picking could lead to information loss. This study adds towards better identification of diverse groups of parameters offering potentially clinically relevant information and improved functional diagnostics for patients with NP.
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Affiliation(s)
| | - Jernej Rosker
- Faculty of Health Sciences, University of Primorska, Koper, Slovenia.
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Dotov D, Motsenyat A, Trainor LJ. Concurrent Supra-Postural Auditory-Hand Coordination Task Affects Postural Control: Using Sonification to Explore Environmental Unpredictability in Factors Affecting Fall Risk. SENSORS (BASEL, SWITZERLAND) 2024; 24:1994. [PMID: 38544259 PMCID: PMC10974305 DOI: 10.3390/s24061994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/10/2024] [Accepted: 03/18/2024] [Indexed: 04/01/2024]
Abstract
Clinical screening tests for balance and mobility often fall short of predicting fall risk. Cognitive distractors and unpredictable external stimuli, common in busy natural environments, contribute to this risk, especially in older adults. Less is known about the effects of upper sensory-motor coordination, such as coordinating one's hand with an external stimulus. We combined movement sonification and affordable inertial motion sensors to develop a task for the precise measurement and manipulation of full-body interaction with stimuli in the environment. In a double-task design, we studied how a supra-postural activity affected quiet stance. The supra-postural task consisted of rhythmic synchronization with a repetitive auditory stimulus. The stimulus was attentionally demanding because it was being modulated continuously. The participant's hand movement was sonified in real time, and their goal was to synchronize their hand movement with the stimulus. In the unpredictable condition, the tempo changed at random points in the trial. A separate sensor recorded postural fluctuations. Young healthy adults were compared to older adult (OA) participants without known risk of falling. The results supported the hypothesis that supra-postural coordination would entrain postural control. The effect was stronger in OAs, supporting the idea that diminished reserve capacities reduce the ability to isolate postural control from sensory-motor and cognitive activity.
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Affiliation(s)
- Dobromir Dotov
- Department of Biomechanics, University of Nebraska Omaha, Omaha, NE 68182, USA
- Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON L8S 4K1, Canada;
| | - Ariel Motsenyat
- Integrated Biomedical Engineering and Health Science, McMaster University, Hamilton, ON L8S 4K1, Canada;
| | - Laurel J. Trainor
- Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON L8S 4K1, Canada;
- Rotman Research Institute, Toronto, ON M6A 2E1, Canada
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7
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De SD, Ricotta JM, Benamati A, Latash ML. Two classes of action-stabilizing synergies reflecting spinal and supraspinal circuitry. J Neurophysiol 2024; 131:152-165. [PMID: 38116603 DOI: 10.1152/jn.00352.2023] [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: 09/20/2023] [Revised: 11/30/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023] Open
Abstract
We explored force-stabilizing synergies during accurate four-finger constant force production tasks in spaces of finger modes (commands to fingers computed to account for the finger interdependence) and of motor unit (MU) firing frequencies. The main specific hypothesis was that the multifinger synergies would disappear during unintentional force drifts without visual feedback on the force magnitude, whereas MU-based synergies would be robust to such drifts. Healthy participants performed four-finger accurate cyclical force production trials followed by trials of constant force production. Individual MUs were identified in the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC). Principal component analysis was applied to motor unit frequencies to identify robust MU groups (MU-modes) with parallel scaling of the firing frequencies in FDS, in EDC, and the combined MUs of FDS + EDC. The framework of the uncontrolled manifold hypothesis was used to quantify force-stabilizing synergies when visual feedback on the force magnitude was available and 15 s after turning the visual feedback off. Removing visual feedback led to a force drift toward lower magnitudes, accompanied by the disappearance of multifinger synergies. In contrast, MU-mode synergies were minimally affected by removing visual feedback off and continued to be robust for the FDS and for the EDC, while being absent for the (FDS + EDC) analysis. We interpret the findings within the theory of hierarchical control of action with spatial referent coordinates. The qualitatively different behavior of the multifinger and MU-mode-based synergies likely reflects the difference in the involved neural circuitry, supraspinal for the former and spinal for the latter.NEW & NOTEWORTHY Two types of synergies, in the space of commands to individual fingers and in the space of motor unit groups, show qualitatively different behaviors during accurate multifinger force-production tasks. After removing visual feedback, finger force synergies disappear, whereas motor unit-based synergies persist. These results point at different neural circuitry involved in these two basic classes of synergies: supraspinal for multieffector synergies, and spinal for motor unit-based synergies.
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Affiliation(s)
- Sayan Deep De
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Joseph M Ricotta
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Anna Benamati
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
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8
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Ricotta JM, De SD, Nardon M, Benamati A, Latash ML. Effects of fatigue on intramuscle force-stabilizing synergies. J Appl Physiol (1985) 2023; 135:1023-1035. [PMID: 37732378 DOI: 10.1152/japplphysiol.00419.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/22/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023] Open
Abstract
We applied the recently introduced concept of intramuscle synergies in spaces of motor units (MUs) to quantify indexes of such synergies in the tibialis anterior during ankle dorsiflexion force production tasks and their changes with fatigue. We hypothesized that MUs would be organized into robust groups (MU modes), which would covary across trials to stabilize force magnitude, and the indexes of such synergies would drop under fatigue. Healthy, young subjects (n = 15; 8 females) produced cyclical, isometric dorsiflexion forces while surface electromyography was used to identify action potentials of individual MUs. Principal component analysis was used to define MU modes. The framework of the uncontrolled manifold (UCM) was used to analyze intercycle variance and compute the synergy index, ΔVZ. Cyclical force production tasks were repeated after a nonfatiguing exercise (control) and a fatiguing exercise. Across subjects, fatigue led, on average, to a 43% drop in maximal force and fewer identified MUs per subject (29.6 ± 2.1 vs. 32.4 ± 2.1). The first two MU modes accounted for 81.2 ± 0.08% of variance across conditions. Force-stabilizing synergies were present across all conditions and were diminished after fatiguing exercise (1.49 ± 0.40) but not control exercise (1.76 ± 0.75). Decreased stability after fatigue was caused by an increase in the amount of variance orthogonal to the UCM. These findings contrast with earlier studies of multieffector synergies demonstrating increased synergy index under fatigue. We interpret the results as reflections of a drop in the gain of spinal reflex loops under fatigue. The findings corroborate an earlier hypothesis on the spinal nature of intramuscle synergies.NEW & NOTEWORTHY Across multielement force production tasks, fatigue of an element leads to increased indexes of force stability (synergy indexes). Here, however, we show that groups of motor units in the tibialis anterior show decreased indexes of force-stabilizing synergies after fatiguing exercise. These findings align intramuscle synergies with spinal mechanisms, in contrast to the supraspinal control of multimuscle synergies.
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Affiliation(s)
- Joseph M Ricotta
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
- Clinical and Translational Science Institute, Penn State College of Medicine, Hershey, Pennsylvania, United States
| | - Sayan D De
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Mauro Nardon
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Anna Benamati
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, United States
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9
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Falaki A, Cuadra C, Lewis MM, Prado-Rico JM, Huang X, Latash ML. Multi-muscle synergies in preparation for gait initiation in Parkinson's disease. Clin Neurophysiol 2023; 154:12-24. [PMID: 37524005 DOI: 10.1016/j.clinph.2023.06.022] [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: 03/16/2023] [Revised: 05/20/2023] [Accepted: 06/25/2023] [Indexed: 08/02/2023]
Abstract
OBJECTIVE We investigated changes in indices of muscle synergies prior to gait initiation and the effects of gaze shift in patients with Parkinson's disease (PD). A long-term objective of the study is to develop a method for quantitative assessment of gait-initiation problems in PD. METHODS PD patients without clinical signs of postural instability and two control groups (age-matched and young) performed a gait initiation task in a self-paced manner, with and without a quick prior gaze shift produced by turning the head. Muscle groups with parallel scaling of activation levels (muscle modes) were identified as factors in the muscle activation space. Synergy index stabilizing center of pressure trajectory in the anterior-posterior and medio-lateral directions (indices of stability) was quantified in the muscle mode space. A drop in the synergy index in preparation to gait initiation (anticipatory synergy adjustment, ASA) was quantified. RESULTS Compared to the control groups, PD patients showed significantly smaller synergy indices and ASA for both directions of the center of pressure shift. Both PD and age-matched controls, but not younger controls, showed detrimental effects of the prior gaze shift on the ASA indices. CONCLUSIONS PD patients without clinically significant posture or gait disorders show impaired stability of the center of pressure and its diminished adjustment during gait initiation. SIGNIFICANCE The indices of stability and ASA may be useful to monitor pre-clinical gait disorders, and lower ASA may be relevant to emergence of freezing of gait in PD.
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Affiliation(s)
- Ali Falaki
- Department of Neurosciences, University of Montreal, Montreal, Quebec, Canada
| | - Cristian Cuadra
- Department of Physical Therapy, Emory University, Atlanta, GA, USA; Exercise and Rehabilitation Sciences Laboratory, School of Physical Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, 7591538 Santiago, Chile
| | - Mechelle M Lewis
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Pharmacology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA
| | - Janina M Prado-Rico
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA
| | - Xuemei Huang
- Department of Neurology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Pharmacology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Radiology, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Neurosurgery, Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA, USA; Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA.
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Pascucci F, Cesari P, Bertucco M, Latash ML. Postural adjustments to self-triggered perturbations under conditions of changes in body orientation. Exp Brain Res 2023:10.1007/s00221-023-06671-0. [PMID: 37479771 PMCID: PMC10386932 DOI: 10.1007/s00221-023-06671-0] [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: 03/02/2023] [Accepted: 07/10/2023] [Indexed: 07/23/2023]
Abstract
We studied anticipatory and compensatory postural adjustments (APAs and CPAs) associated with self-triggered postural perturbations in conditions with changes in the initial body orientation. In particular, we were testing hypotheses on adjustments in the reciprocal and coactivation commands, role of proximal vs. distal muscles, and correlations between changes in indices of APAs and CPAs. Healthy young participants stood on a board with full support or reduced support area and held a standard load in the extended arms. They released the load in a self-paced manned with a standard small-amplitude arm movement. Electromyograms of 12 muscles were recorded and used to compute reciprocal and coactivation indices between three muscle pairs on both sides of the body. The subject's body was oriented toward one of three targets: straight ahead, 60° to the left, and 60° to the right. Body orientation has stronger effects on proximal muscle pairs compared to distal muscles. It led to more consistent changes in the reciprocal command compared to the coactivation command. Indices of APAs and CPAs showed positive correlations across conditions. We conclude that the earlier suggested hierarchical relations between the reciprocal and coactivation command could be task-specific. Predominance of negative or positive correlations between APA and CPA indices could also be task-specific.
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Affiliation(s)
- Francesco Pascucci
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - Paola Cesari
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Via Felice Casorati 43, 37131, Verona, Italy.
| | - Matteo Bertucco
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Via Felice Casorati 43, 37131, Verona, Italy
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
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11
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Schmidt MD, Glasmachers T, Iossifidis I. The concepts of muscle activity generation driven by upper limb kinematics. Biomed Eng Online 2023; 22:63. [PMID: 37355651 DOI: 10.1186/s12938-023-01116-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 05/16/2023] [Indexed: 06/26/2023] Open
Abstract
BACKGROUND The underlying motivation of this work is to demonstrate that artificial muscle activity of known and unknown motion can be generated based on motion parameters, such as angular position, acceleration, and velocity of each joint (or the end-effector instead), which are similarly represented in our brains. This model is motivated by the known motion planning process in the central nervous system. That process incorporates the current body state from sensory systems and previous experiences, which might be represented as pre-learned inverse dynamics that generate associated muscle activity. METHODS We develop a novel approach utilizing recurrent neural networks that are able to predict muscle activity of the upper limbs associated with complex 3D human arm motions. Therefore, motion parameters such as joint angle, velocity, acceleration, hand position, and orientation, serve as input for the models. In addition, these models are trained on multiple subjects (n=5 including , 3 male in the age of 26±2 years) and thus can generalize across individuals. In particular, we distinguish between a general model that has been trained on several subjects, a subject-specific model, and a specific fine-tuned model using a transfer learning approach to adapt the model to a new subject. Estimators such as mean square error MSE, correlation coefficient r, and coefficient of determination R2 are used to evaluate the goodness of fit. We additionally assess performance by developing a new score called the zero-line score. The present approach was compared with multiple other architectures. RESULTS The presented approach predicts the muscle activity for previously through different subjects with remarkable high precision and generalizing nicely for new motions that have not been trained before. In an exhausting comparison, our recurrent network outperformed all other architectures. In addition, the high inter-subject variation of the recorded muscle activity was successfully handled using a transfer learning approach, resulting in a good fit for the muscle activity for a new subject. CONCLUSIONS The ability of this approach to efficiently predict muscle activity contributes to the fundamental understanding of motion control. Furthermore, this approach has great potential for use in rehabilitation contexts, both as a therapeutic approach and as an assistive device. The predicted muscle activity can be utilized to guide functional electrical stimulation, allowing specific muscles to be targeted and potentially improving overall rehabilitation outcomes.
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Affiliation(s)
- Marie D Schmidt
- Faculty of Electrical Engineering and Information Technology, Ruhr-University Bochum, Bochum, Germany.
- Institute of Computer Science, University of Applied Science Ruhr West, Mülheim an der Ruhr, Germany.
| | | | - Ioannis Iossifidis
- Institute of Computer Science, University of Applied Science Ruhr West, Mülheim an der Ruhr, Germany
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12
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Bonifati P, Baracca M, Menolotto M, Averta G, Bianchi M. A Multi-Modal Under-Sensorized Wearable System for Optimal Kinematic and Muscular Tracking of Human Upper Limb Motion. SENSORS (BASEL, SWITZERLAND) 2023; 23:3716. [PMID: 37050776 PMCID: PMC10098930 DOI: 10.3390/s23073716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/24/2023] [Accepted: 03/30/2023] [Indexed: 06/19/2023]
Abstract
Wearable sensing solutions have emerged as a promising paradigm for monitoring human musculoskeletal state in an unobtrusive way. To increase the deployability of these systems, considerations related to cost reduction and enhanced form factor and wearability tend to discourage the number of sensors in use. In our previous work, we provided a theoretical solution to the problem of jointly reconstructing the entire muscular-kinematic state of the upper limb, when only a limited amount of optimally retrieved sensory data are available. However, the effective implementation of these methods in a physical, under-sensorized wearable has never been attempted before. In this work, we propose to bridge this gap by presenting an under-sensorized system based on inertial measurement units (IMUs) and surface electromyography (sEMG) electrodes for the reconstruction of the upper limb musculoskeletal state, focusing on the minimization of the sensors' number. We found that, relying on two IMUs only and eight sEMG sensors, we can conjointly reconstruct all 17 degrees of freedom (five joints, twelve muscles) of the upper limb musculoskeletal state, yielding a median normalized RMS error of 8.5% on the non-measured joints and 2.5% on the non-measured muscles.
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Affiliation(s)
- Paolo Bonifati
- Research Center “E. Piaggio”, Department of Information Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa, Italy
| | - Marco Baracca
- Research Center “E. Piaggio”, Department of Information Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa, Italy
| | - Mariangela Menolotto
- Research Center “E. Piaggio”, Department of Information Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa, Italy
| | - Giuseppe Averta
- Department of Control and Computer Engineering, Politecnico di Torino, 10129 Torino, Italy
| | - Matteo Bianchi
- Research Center “E. Piaggio”, Department of Information Engineering, University of Pisa, Largo Lucio Lazzarino 1, 56126 Pisa, Italy
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Cartier T, Rao G, Viehweger E, Vigouroux L. Evolution of muscle coordination and mechanical output following four weeks of arm cranking submaximal training. J Neurophysiol 2023; 129:541-551. [PMID: 36695521 DOI: 10.1152/jn.00425.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Muscle synergies is extensively studied to understand how the neuromusculoskeletal system deals with abundancy. The synergies represent covariant muscles that acts as building blocks for movement production. Nevertheless, little is known on how those synergies evolve following training, learning and expertise. This study reports the influence a 4-weeks submaximal training of arm-cranking on novice participants' muscle synergies. METHODS 12 participants performed 8 sessions of submaximal training for 4 weeks. One session consisted in two 30-second-maximal power tests followed by six 2-minutes-bouts at 30% of maximal recorded power. Cranking torque and EMG of 11 muscles were recorded during the entire protocol. After EMG normalization, muscle synergies were extracted using NNMF. Similarity was computed using cross-correlation and cosine similarities and statistical evolution across training was tested using repeated measured ANOVA. RESULTS While maximal power increased across training days nor torque management, EMG or muscle synergies were significantly affected by submaximal training. Nevertheless, results suggest slights modifications of muscle synergies across day despite to non-significant differences. DISCUSSION Despite the strong complexity of the upper limbs anatomy, our results showed that training didn't induce significant changes in movement realization (mechanical and coordination level). A low-dimensional organization of muscle synergies is selected from the first day and kept through the following training days, despite slight but non-significant modifications.This study supports the hypothesis that motor control for movement production could be simplify using low-dimensional building blocks (muscle synergies). Such building blocks allow stability in movement execution and are slightly adjusted to fit movement requirements with training.
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Affiliation(s)
- Théo Cartier
- Aix Marseille Univ, CNRS, ISM, Marseille, France
| | | | - Elke Viehweger
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
- Department of Orthopedics and Gait Laboratory, University Children's Hospital of Both Basel (UKBB), Basel, Switzerland
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14
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Between a Walk and a Hard Place: How Stepping Patterns Change While Navigating Environmental Obstacles. Motor Control 2023; 27:20-34. [PMID: 36049749 DOI: 10.1123/mc.2022-0045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 07/01/2022] [Accepted: 07/18/2022] [Indexed: 01/04/2023]
Abstract
Maintaining a consistent relationship between each footfall and the body's motion is a key mechanism to maintain balance while walking. However, environmental features, for example, puddles/obstacles, impose additional constraints on foot placement. This study investigated how healthy young individuals alter foot placements to simultaneously manage body-centric and environmental constraints during an obstacle-crossing task. Consistent step length promotes balance for all steps, whereas accurate foot placement around the obstacle is essential to avoid a trip. While crossing an obstacle, any error in positioning one foot relative to the obstacle can be compensated by selecting the placement of the subsequent step. However, compensation will necessarily alter step length from its average value. The interstep covariance index computed from two consecutive foot placements was used to quantify this tradeoff between body-centric and environmental constraints for six consecutive steps while approaching, crossing, and resuming unobstructed gait after crossing the obstacle. The index declined only when either one or both feet were adjacent to the obstacle. The decline was driven in part by a tendency toward higher step length variability. Thus, changes in the stepping patterns to address the environmental constraint occurred at the cost of the body-centric constraint. However, the step length never ceased to be controlled; the interstep covariance index was positive for all steps. Overall, participants adapted foot placement control to account for the larger threat to balance. The environmental constraint was prioritized only when a potential trip posed greater threat to balance compared with the threat posed by variable step length.
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15
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Intra-muscle Synergies Stabilizing Reflex-mediated Force Changes. Neuroscience 2022; 505:59-77. [DOI: 10.1016/j.neuroscience.2022.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/23/2022] [Accepted: 10/10/2022] [Indexed: 11/20/2022]
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16
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Singh H, Shih HT, Kal E, Bennett T, Wulf G. A distal external focus of attention facilitates compensatory coordination of body parts. J Sports Sci 2022; 40:2282-2291. [PMID: 36418176 DOI: 10.1080/02640414.2022.2150419] [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: 11/27/2022]
Abstract
Many studies have shown that focusing on an intended movement effect that is farther away from the body (distal external focus) results in performance benefits relative to focusing on an effect that is closer to the body (proximal external focus) or focusing on the body itself (internal focus) (see, Chua, Jimenez-Diaz, Lewthwaite, Kim & Wulf, 2021). Furthermore, the advantages of a distal external focus seem to be particularly pronounced in skilled performers (Singh & Wulf, 2020). The present study examined whether such benefits of more distal attentional focus may be associated with enhanced functional variability. Volleyball players (n = 20) performed 60 overhand volleyball serves to a target. Using a within-participants design, the effects of a distal external focus (bullseye), proximal external focus (ball) and an internal focus (hand) were compared. The distal focus condition resulted in significantly higher accuracy scores than did the proximal and internal focus conditions. In addition, uncontrolled manifold analysis showed that functional variability (as measured by the index of synergy) was greatest in the distal focus condition. These findings suggest that a distal external focus on the task goal may enhance movement outcomes by optimising compensatory coordination of body parts.
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Affiliation(s)
- Harjiv Singh
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA.,Orlando Magic Basketball Club, Orlando, FL, USA
| | - Hui-Ting Shih
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA
| | - Elmar Kal
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
| | - Tim Bennett
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - Gabriele Wulf
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA
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17
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Corcos DM, Myklebust BM, Latash ML. The legacy of Gerald L. Gottlieb in human movement neuroscience. J Neurophysiol 2022; 128:148-159. [PMID: 35675443 DOI: 10.1152/jn.00141.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this paper, we review the legacy of Gerald (Gerry) Gottlieb in various fields related to the neural control of human movement. His studies on the myotatic (stretch) reflex and postmyotatic responses to ankle joint perturbations paved the way for current explorations of long-loop reflexes and their role in the control of movement. The dual-strategy hypothesis introduced order into a large body of literature on the triphasic muscle activation patterns seen over a variety of voluntary movements in healthy persons. The dual-strategy hypothesis continues to be important for understanding the performance of subjects with disordered motor control. The principle of linear synergy (covariance of joint torques) was an attempt to solve one of the notorious problems of motor redundancy, which remains an important topic in the field. Gerry's attitude toward the equilibrium-point hypothesis varied between rejection and using it to explore patterns of hypothetical control variables and movement variability. The discovery of reciprocal excitation in healthy neonates fostered other studies of changes in spinal cord physiology as motor skills develop. In addition, studies of people with spasticity and the effects of treatment with intrathecal baclofen were crucial in demonstrating the possibility of unmasking voluntary movements after suppression of the hyperreflexia of spasticity. Gerry Gottlieb contributed a significant body of knowledge that formed a solid foundation from which to study a variety of neurological diseases and their treatments, and a more comprehensive and parsimonious foundation to describe the neural control of human movement.
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Affiliation(s)
- Daniel M Corcos
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Barbara M Myklebust
- Retired from the Office of Surveillance and Biometrics and the Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
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18
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Madarshahian S, Latash ML. Effects of hand muscle function and dominance on intra-muscle synergies. Hum Mov Sci 2022; 82:102936. [PMID: 35217391 DOI: 10.1016/j.humov.2022.102936] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/09/2022] [Accepted: 02/13/2022] [Indexed: 11/04/2022]
Abstract
The goal of the study was to explore the effects of hand dominance and muscle function (prime mover vs. supporting muscle) on recently discovered intra-muscle synergies as potential windows into their neural origin. Healthy right-handed subjects performed accurate cyclical force production tasks while pressing with the middle phalanges and distal phalanges of the fingers of the dominant and non-dominant hand. Surface electromyography was used to identify individual motor unit action potentials in two muscles, flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC). Stable motor unit groups (MU-modes) were defined in each muscle and in both muscles together. The composition of the MU-modes allowed linking them to the reciprocal and co-activation command. Force-stabilizing synergies were quantified in each hand and during force production at both sites using the framework of the uncontrolled manifold hypothesis. Force-stabilizing synergies were seen in the spaces of MU-modes from FDS and EDC separately, but not of MU-modes defined for both muscles together. Synergy indices were similar for both hands and both sites of force application. In contrast, force-stabilizing synergies in the space of finger forces were present in the non-dominant hand and absent in the dominant hand. The data suggest existence of distributed mechanisms of synergic control. Finger force synergies are likely to reflect functioning of subcortical loops involving the basal ganglia and cerebellum, while MU-mode synergies are likely to reflect spinal circuitry. Studies of both force-based and motor-unit-based synergies may be clinically valuable for distinguishing effects of spinal and supraspinal disorders.
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Affiliation(s)
- Shirin Madarshahian
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Mark L Latash
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
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Intramuscle Synergies: Their Place in the Neural Control Hierarchy. Motor Control 2022; 27:402-441. [PMID: 36543175 DOI: 10.1123/mc.2022-0094] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/03/2022] [Accepted: 10/24/2022] [Indexed: 12/24/2022]
Abstract
We accept a definition of synergy introduced by Nikolai Bernstein and develop it for various actions, from those involving the whole body to those involving a single muscle. Furthermore, we use two major theoretical developments in the field of motor control—the idea of hierarchical control with spatial referent coordinates and the uncontrolled manifold hypothesis—to discuss recent studies of synergies within spaces of individual motor units (MUs) recorded within a single muscle. During the accurate finger force production tasks, MUs within hand extrinsic muscles form robust groups, with parallel scaling of the firing frequencies. The loading factors at individual MUs within each of the two main groups link them to the reciprocal and coactivation commands. Furthermore, groups are recruited in a task-specific way with gains that covary to stabilize muscle force. Such force-stabilizing synergies are seen in MUs recorded in the agonist and antagonist muscles but not in the spaces of MUs combined over the two muscles. These observations reflect inherent trade-offs between synergies at different levels of a control hierarchy. MU-based synergies do not show effects of hand dominance, whereas such effects are seen in multifinger synergies. Involuntary, reflex-based, force changes are stabilized by intramuscle synergies but not by multifinger synergies. These observations suggest that multifinger (multimuscle synergies) are based primarily on supraspinal circuitry, whereas intramuscle synergies reflect spinal circuitry. Studies of intra- and multimuscle synergies promise a powerful tool for exploring changes in spinal and supraspinal circuitry across patient populations.
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