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Interfinger Synchronization Capability of Paired Fingers in Discrete Fine-Force Control Tasks. Motor Control 2022; 26:608-629. [PMID: 35902076 DOI: 10.1123/mc.2021-0117] [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: 10/06/2021] [Revised: 06/04/2022] [Accepted: 06/10/2022] [Indexed: 11/18/2022]
Abstract
This study examined whether within-a-hand and between-hands finger pairings would exhibit different interfinger synchronization capabilities in discrete fine-force control tasks. Participants were required to perform the designed force control tasks using finger pairings of index and middle fingers on one or two hands. Results demonstrated that the delayed reaction time and the timing difference of paired fingers showed a significant difference among finger pairings. In particular, paired fingers exhibited less delayed reaction time and timing difference in between-hands finger pairings than in within-a-hand finger pairings. Such bimanual advantage of the pairings with two symmetric fingers was evident only in the task types with relatively high amplitudes. However, for a given finger pairing, the asymmetric amplitude configuration, assigning a relatively higher amplitude to either left or right finger of paired fingers, has no significant effect on the interfinger synchronization. Therefore, paired fingers on both hands showed a bimanual advantage in the relatively high force, especially for the pairing of symmetrical fingers, whereas asymmetric amplitude configuration for a finger pairing was able to suppress the bimanual advantage. These findings would enrich the understanding of the interfinger synchronization capability of paired fingers and be referential for interactive engineering applications when leveraging the interfinger synchronization capability in discrete fine-force control tasks.
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2
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Hibino H, Gorniak SL. Effects of aging on rapid grip force responses during bimanual manipulation of an active object. Exp Brain Res 2020; 238:2161-2178. [PMID: 32661648 PMCID: PMC10103105 DOI: 10.1007/s00221-020-05865-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/01/2020] [Indexed: 12/17/2022]
Abstract
Rapid grip force responses to unexpected pulling loads on the fingertips are deteriorated in older adults due to, in part, age-related declines in somatosensory function. Such reports are limited to one-hand conditions despite the higher frequency of using two hands together in daily living activities of older adults. Unexpected perturbations during bimanual movements elicit goal-oriented and cortically-meditated bilateral rapid motor responses. Since aging is associated with declined somatosensory and cognitive functions, we hypothesized that bilateral rapid motor responses differ between young and older adults, such that older adults exert stronger grip forces following perturbation and the unperturbed hand is more involved in stabilizing the object in older adults. We tested our hypothesis by comparing the rapid grip force responses of both hands in young and older adults. A total of 13 right-handed young individuals (24.2 ± 4.0 years old, 5 men) and 13 right-handed older individuals (68.7 ± 7.1 years old, 5 men) were recruited. Tactile detection threshold, fingertip friction, and the rapid grip force responses of both hands triggered by unpredicted pulling loads during grip-lift movements were assessed. Older adults had higher tactile detection thresholds and lower fingertip friction compared to young adults. Regardless of age, rapid motor responses were found in both the perturbed (right) hand and the indirectly perturbed (left) hand at 73 ms and 135 ms after the perturbation, respectively, while magnitudes of the responses depended on perturbation magnitudes. Higher values in maximum grip force and maximum grip force rate were found in older adults as compared to young adults. In older adults, the indirectly perturbed (left) hand was more involved in stabilizing the object as compared to young healthy adults. The current study suggests that age-related changes in the peripheral and central nervous systems contribute to the greater involvement of the indirectly perturbed hand in older adults.
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Affiliation(s)
- Hidetaka Hibino
- Department of Health and Human Performance, University of Houston, 3855 Holman St., Garrison 104, Houston, TX, 77204-6015, USA
| | - Stacey L Gorniak
- Department of Health and Human Performance, University of Houston, 3855 Holman St., Garrison 104, Houston, TX, 77204-6015, USA.
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3
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Reschechtko S, Pruszynski JA. Voluntary modification of rapid tactile-motor responses during reaching differs from its visuomotor counterpart. J Neurophysiol 2020; 124:284-294. [PMID: 32584635 PMCID: PMC7474452 DOI: 10.1152/jn.00232.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 01/01/2023] Open
Abstract
People commonly hold and manipulate a variety of objects in everyday life, and these objects have different physical properties. To successfully control this wide range of objects, people must associate new patterns of tactile stimuli with appropriate motor outputs. We performed a series of experiments investigating the extent to which people can voluntarily modify tactile-motor associations in the context of a rapid tactile-motor response guiding the hand to a moving target (previously described in Pruszynski JA, Johansson RS, Flanagan JR. Curr Biol 26: 788-792, 2016) by using an anti-reach paradigm in which participants were instructed to move their hands in the opposite direction of a target jump. We compared performance to that observed when people make visually guided reaches to a moving target (cf. Day BL, Lyon IN. Exp Brain Res 130: 159-168, 2000; Pisella L, Grea H, Tilikete C, Vighetto A, Desmurget M, Rode G, Boisson D, Rossetti Y. Nat Neurosci 3: 729-736, 2000). When participants had visual feedback, motor responses during the anti-reach task showed early automatic responses toward the moving target before later modification to move in the instructed direction. When the same participants had only tactile feedback, however, they were able to suppress this early phase of the motor response, which occurs <100 ms after the target jump. Our results indicate that while the tactile motor and visual motor systems both support rapid responses that appear similar under some conditions, the circuits underlying responses show sharp distinctions in terms of their malleability.NEW & NOTEWORTHY When people reach toward a visual target that moves suddenly, they automatically correct their reach to follow the object; even when explicitly instructed not to follow a moving visual target, people exhibit an initial incorrect movement before moving in the correct direction. We show that when people use tactile feedback, they do not show an initial incorrect response, even though early muscle activity still occurs.
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Affiliation(s)
- Sasha Reschechtko
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
- BrainsCAN, Western University, London, Ontario, Canada
- Brain and Mind Institute, Western University, London, Ontario, Canada
| | - J Andrew Pruszynski
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
- Department of Psychology, Western University, London, Ontario, Canada
- BrainsCAN, Western University, London, Ontario, Canada
- Brain and Mind Institute, Western University, London, Ontario, Canada
- Robarts Research Institute, Western University, London, Ontario, Canada
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4
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Khong KYW, Galán F, Soteropoulos DS. Rapid crossed responses in an intrinsic hand muscle during perturbed bimanual movements. J Neurophysiol 2019; 123:630-644. [PMID: 31851557 PMCID: PMC7052646 DOI: 10.1152/jn.00282.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mechanical perturbations in one upper limb often elicit corrective responses in both the perturbed as well as its contralateral and unperturbed counterpart. These crossed corrective responses have been shown to be sensitive to the bimanual requirements of the perturbation, but crossed responses (CRs) in hand muscles are far less well studied. Here, we investigate corrective CRs in an intrinsic hand muscle, the first dorsal interosseous (1DI), to clockwise and anticlockwise mechanical perturbations to the contralateral index finger while participants performed a bimanual finger abduction task. We found that the CRs in the unperturbed 1DI were sensitive to the direction of the perturbation of the contralateral index finger. However, the size of the CRs was not sensitive to the amplitude of the contralateral perturbation nor its context within the bimanual task. The onset latency of the CRs was too fast to be purely transcortical (<70 ms) in 12/12 participants. This confirms that during isolated bimanual finger movements, sensory feedback from one hand can influence the other, but the pathways mediating the earliest components of this interaction are likely to involve subcortical systems such as the brainstem or spinal cord, which may afford less flexibility to the task demands.NEW & NOTEWORTHY An intrinsic hand muscle shows a crossed response to a perturbation of the contralateral index finger. The crossed response is dependent on the direction of the contralateral perturbation but not on the amplitude or the bimanual requirements of the movement, suggesting a far less flexible control policy than those governing crossed responses in more proximal muscles. The crossed response is too fast to be purely mediated by transcortical pathways, suggesting subcortical contributions.
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Affiliation(s)
- Katie Y W Khong
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.,Queen's University Belfast, Belfast, Northern Ireland
| | - Ferran Galán
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.,Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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5
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Sun Y, Zehr EP. Sensory enhancement amplifies interlimb cutaneous reflexes in wrist extensor muscles. J Neurophysiol 2019; 122:2085-2094. [PMID: 31509473 DOI: 10.1152/jn.00324.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Interlimb neural connections support motor tasks such as locomotion and cross-education strength training. Somatosensory pathways that can be assessed with cutaneous reflex paradigms assist in subserving these connections. Many studies show that stimulation of cutaneous nerves elicits reflexes in muscles widespread across the body and induces neural plasticity after training. Sensory enhancement, such as long-duration trains of transcutaneous stimulation, facilitates performance during rehabilitation training or fatiguing motor tasks. Performance improvements due to sensory stimulation may be caused by altered spinal and corticospinal excitability. However, how enhanced sensory input regulates the excitability of interlimb cutaneous reflex pathways has not been studied. Our purpose was to investigate the effects of sensory enhancement on interlimb cutaneous reflexes in wrist extensor muscles. Stimulation to provide sensory enhancement (2-s trains at 150 Hz to median or superficial radial nerves) or evoke cutaneous reflexes (15-ms trains at 300 Hz to superficial radial nerve) was applied in different arms while participants (n = 13) performed graded isometric wrist extension. Wrist extensor electromyography and cutaneous reflexes were measured bilaterally. We found amplified inhibitory reflexes in the arm receiving superficial radial and median nerve sensory enhancement with net reflex amplitudes decreased by 709.5% and 695.3% repetitively. This suggests sensory input alters neuronal excitabilities in the interlimb cutaneous pathways. These findings have potential application in facilitating motor function recovery through alterations in spinal cord excitability enhancing sensory input during targeted rehabilitation and sports training.NEW & NOTEWORTHY We show that sensory enhancement increases excitability in interlimb cutaneous pathways and that these effects are not influenced by descending motor drive on the contralateral side. These findings confirm the role of sensory input and cutaneous pathways in regulating interlimb movements. In targeted motor function training or rehabilitation, sensory enhancement may be applied to facilitate outcomes.
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Affiliation(s)
- Yao Sun
- Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, British Columbia, Canada.,Human Discovery Science, International Collaboration on Repair Discovery, Vancouver, British Columbia, Canada.,Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada
| | - E Paul Zehr
- Rehabilitation Neuroscience Laboratory, University of Victoria, Victoria, British Columbia, Canada.,Human Discovery Science, International Collaboration on Repair Discovery, Vancouver, British Columbia, Canada.,Centre for Biomedical Research, University of Victoria, Victoria, British Columbia, Canada.,Division of Medical Science, University of Victoria, Victoria, British Columbia, Canada.,Zanshin Consulting, Inc., Victoria, British Columbia, Canada
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6
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Weiler J, Saravanamuttu J, Gribble PL, Pruszynski JA. Coordinating long-latency stretch responses across the shoulder, elbow, and wrist during goal-directed reaching. J Neurophysiol 2016; 116:2236-2249. [PMID: 27535378 DOI: 10.1152/jn.00524.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022] Open
Abstract
The long-latency stretch response (muscle activity 50-100 ms after a mechanical perturbation) can be coordinated across multiple joints to support goal-directed actions. Here we assessed the flexibility of such coordination and whether it serves to counteract intersegmental dynamics and exploit kinematic redundancy. In three experiments, participants made planar reaches to visual targets after elbow perturbations and we assessed the coordination of long-latency stretch responses across shoulder, elbow, and wrist muscles. Importantly, targets were placed such that elbow and wrist (but not shoulder) rotations could help transport the hand to the target-a simple form of kinematic redundancy. In experiment 1 we applied perturbations of different magnitudes to the elbow and found that long-latency stretch responses in shoulder, elbow, and wrist muscles scaled with perturbation magnitude. In experiment 2 we examined the trial-by-trial relationship between long-latency stretch responses at adjacent joints and found that the magnitudes of the responses in shoulder and elbow muscles, as well as elbow and wrist muscles, were positively correlated. In experiment 3 we explicitly instructed participants how to use their wrist to move their hand to the target after the perturbation. We found that long-latency stretch responses in wrist muscles were not sensitive to our instructions, despite the fact that participants incorporated these instructions into their voluntary behavior. Taken together, our results indicate that, during reaching, the coordination of long-latency stretch responses across multiple joints counteracts intersegmental dynamics but may not be able to exploit kinematic redundancy.
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Affiliation(s)
- Jeffrey Weiler
- Brain and Mind Institute, Western University, London, Ontario, Canada; .,Department of Psychology, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - James Saravanamuttu
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - Paul L Gribble
- Brain and Mind Institute, Western University, London, Ontario, Canada.,Department of Psychology, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - J Andrew Pruszynski
- Brain and Mind Institute, Western University, London, Ontario, Canada.,Department of Psychology, Western University, London, Ontario, Canada.,Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.,Robarts Research Institute, Western University, London, Ontario, Canada; and.,Department of Integrative Medical Biology, Umea University, Umea, Sweden
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Ochoa N, Gogola GR, Gorniak SL. Contribution of tactile dysfunction to manual motor dysfunction in type II diabetes. Muscle Nerve 2016; 54:895-902. [PMID: 27061801 PMCID: PMC6645679 DOI: 10.1002/mus.25137] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/15/2016] [Accepted: 04/05/2016] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Changes in sensory and motor functions of the hand in type II diabetes (T2D) patients have been reported; there is speculation that these changes are driven by tactile dysfunction. The purpose of this study was to evaluate the effects of tactile feedback on manual function in T2D patients. METHODS T2D patients and healthy controls underwent median nerve blocks at the wrist and elbow. All participants underwent traditional timed motor evaluations, force dynamometry, laboratory-based kinetic evaluations, and sensory evaluation. RESULTS Tactile sensation in the T2D group at baseline was found to be equivalent to tactile function of the control group after median nerve block. Traditional timed evaluation results were negatively impacted by anesthesia, but more sensitive kinetic measures were not impacted. CONCLUSIONS These data suggest that mechanisms outside of tactile dysfunction play a significant role in motor dysfunction in T2D. Muscle Nerve 54: 895-902, 2016.
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Affiliation(s)
- Nereyda Ochoa
- Department of Health and Human Performance, University of Houston, 3875 Holman Street, Garrison 104N, Houston, Texas, 77204, USA.,Center for Neuromotor and Biomechanics Research, University of Houston, Houston, Texas, USA
| | - Gloria R Gogola
- Hand and Upper Extremity Surgery, Shriners Hospitals for Children, Houston, Houston, Texas, USA
| | - Stacey L Gorniak
- Department of Health and Human Performance, University of Houston, 3875 Holman Street, Garrison 104N, Houston, Texas, 77204, USA. .,Center for Neuromotor and Biomechanics Research, University of Houston, Houston, Texas, USA. .,Texas Obesity Research Center, University of Houston, Houston, Texas, USA.
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8
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Weiler J, Gribble PL, Pruszynski JA. Goal-dependent modulation of the long-latency stretch response at the shoulder, elbow, and wrist. J Neurophysiol 2015; 114:3242-54. [PMID: 26445871 DOI: 10.1152/jn.00702.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/30/2015] [Indexed: 12/17/2022] Open
Abstract
Many studies have demonstrated that muscle activity 50-100 ms after a mechanical perturbation (i.e., the long-latency stretch response) can be modulated in a manner that reflects voluntary motor control. These previous studies typically assessed modulation of the long-latency stretch response from individual muscles rather than how this response is concurrently modulated across multiple muscles. Here we investigated such concurrent modulation by having participants execute goal-directed reaches to visual targets after mechanical perturbations of the shoulder, elbow, or wrist while measuring activity from six muscles that articulate these joints. We found that shoulder, elbow, and wrist muscles displayed goal-dependent modulation of the long-latency stretch response, that the relative magnitude of participants' goal-dependent activity was similar across muscles, that the temporal onset of goal-dependent muscle activity was not reliably different across the three joints, and that shoulder muscles displayed goal-dependent activity appropriate for counteracting intersegmental dynamics. We also observed that the long-latency stretch response of wrist muscles displayed goal-dependent modulation after elbow perturbations and that the long-latency stretch response of elbow muscles displayed goal-dependent modulation after wrist perturbations. This pattern likely arises because motion at either joint could bring the hand to the visual target and suggests that the nervous system rapidly exploits such simple kinematic redundancy when processing sensory feedback to support goal-directed actions.
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Affiliation(s)
- Jeffrey Weiler
- Brain and Mind Institute, Western University, London, Ontario, Canada; Department of Psychology, Western University, London, Ontario, Canada;
| | - Paul L Gribble
- Brain and Mind Institute, Western University, London, Ontario, Canada; Department of Psychology, Western University, London, Ontario, Canada; Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; and
| | - J Andrew Pruszynski
- Brain and Mind Institute, Western University, London, Ontario, Canada; Department of Psychology, Western University, London, Ontario, Canada; Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; and Robarts Research Institute, Western University, London, Ontario, Canada
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9
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Schrafl-Altermatt M, Dietz V. Cooperative hand movements in post-stroke subjects: Neural reorganization. Clin Neurophysiol 2015; 127:748-754. [PMID: 26275809 DOI: 10.1016/j.clinph.2015.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/01/2015] [Accepted: 07/05/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Recent research indicates a task-specific neural coupling controlling cooperative hand movements reflected in bilateral electromyographic reflex responses in arm muscles following unilateral nerve stimulation. Reorganization of this mechanism was explored in post-stroke patients in this study. METHODS Electromyographic reflex responses in forearm muscles to unilateral electrical ulnar nerve stimulation were examined during cooperative and non-cooperative hand movements. RESULTS Stimulation of the unaffected arm during cooperative hand movements led to electromyographic responses in bilateral forearm muscles, similar to those seen in healthy subjects, while stimulation of the affected side was followed only by ipsilateral responses. No contralateral reflex responses could be evoked in severely affected patients. The presence of contralateral responses correlated with the clinical motor impairment as assessed by the Fugl-Meyer test. CONCLUSION The observations suggest that after stroke an impaired processing of afferent input from the affected side leads to a defective neural coupling and is associated with a greater involvement of fiber tracts from the unaffected hemisphere during cooperative hand movements. SIGNIFICANCE The mechanism of neural coupling underlying cooperative hand movements is shown to be defective in post-stroke patients. The neural re-organizations observed have consequences for the rehabilitation of hand function.
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Affiliation(s)
| | - Volker Dietz
- Spinal Cord Injury Center, Balgrist University Hospital, 8008 Zurich, Switzerland
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10
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Pruszynski JA. Primary motor cortex and fast feedback responses to mechanical perturbations: a primer on what we know now and some suggestions on what we should find out next. Front Integr Neurosci 2014; 8:72. [PMID: 25309359 PMCID: PMC4164001 DOI: 10.3389/fnint.2014.00072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 08/29/2014] [Indexed: 11/26/2022] Open
Abstract
Many researchers have drawn a clear distinction between fast feedback responses to mechanical perturbations (e.g., stretch responses) and voluntary control processes. But this simple distinction is difficult to reconcile with growing evidence that long-latency stretch responses share most of the defining capabilities of voluntary control. My general view—and I believe a growing consensus—is that the functional similarities between long-latency stretch responses and voluntary control processes can be readily understood based on their shared neural circuitry, especially a transcortical pathway through primary motor cortex. Here I provide a very brief and selective account of the human and monkey studies linking a transcortical pathway through primary motor cortex to the generation and functional sophistication of the long-latency stretch response. I then lay out some of the notable issues that are ready to be answered.
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Affiliation(s)
- J Andrew Pruszynski
- Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
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11
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Detecting subtle fingertip sensory and motor dysfunction in adults with type II diabetes. Exp Brain Res 2014; 232:1283-91. [DOI: 10.1007/s00221-014-3844-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/11/2014] [Indexed: 11/26/2022]
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12
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Dietz V, Macauda G, Schrafl-Altermatt M, Wirz M, Kloter E, Michels L. Neural coupling of cooperative hand movements: a reflex and fMRI study. ACTA ACUST UNITED AC 2013; 25:948-58. [PMID: 24122137 DOI: 10.1093/cercor/bht285] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The neural control of "cooperative" hand movements reflecting "opening a bottle" was explored in human subjects by electromyographic (EMG) and functional magnetic resonance imaging (fMRI) recordings. EMG responses to unilateral nonnoxious ulnar nerve stimulation were analyzed in the forearm muscles of both sides during dynamic movements against a torque applied by the right hand to a device which was compensated for by the left hand. For control, stimuli were applied while task was performed in a static/isometric mode and during bilateral synchronous pro-/supination movements. During the dynamic cooperative task, EMG responses to stimulations appeared in the right extensor and left flexor muscles, regardless of which side was stimulated. Under the control conditions, responses appeared only on the stimulated side. fMRI recordings showed a bilateral extra-activation and functional coupling of the secondary somatosensory cortex (S2) during the dynamic cooperative, but not during the control, tasks. This activation might reflect processing of shared cutaneous input during the cooperative task. Correspondingly, it is assumed that stimulation-induced unilateral volleys are processed in S2, leading to a release of EMG responses to both forearms. This indicates a task-specific neural coupling during cooperative hand movements, which has consequences for the rehabilitation of hand function in poststroke patients.
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Affiliation(s)
- Volker Dietz
- Spinal Cord Injury Center, Balgrist University Hospital, 8008 Zurich, Switzerland and
| | - Gianluca Macauda
- Clinic of Neuroradiology, University Hospital of Zurich, 8001 Zurich, Switzerland
| | | | - Markus Wirz
- Spinal Cord Injury Center, Balgrist University Hospital, 8008 Zurich, Switzerland and
| | - Evelyne Kloter
- Spinal Cord Injury Center, Balgrist University Hospital, 8008 Zurich, Switzerland and
| | - Lars Michels
- Clinic of Neuroradiology, University Hospital of Zurich, 8001 Zurich, Switzerland
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Omrani M, Diedrichsen J, Scott SH. Rapid feedback corrections during a bimanual postural task. J Neurophysiol 2012; 109:147-61. [PMID: 23054604 DOI: 10.1152/jn.00669.2011] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An important observation in motor physiology is that even the fastest feedback responses can be modified in a task-dependent manner. However, whether or not such responses in one limb can be modulated based on online sensory feedback from other limbs is still unknown. We tested this using a bimanual postural control task, in which the two hands either controlled two separate cursors (double-cursor task) or a single cursor displayed at the spatial average between the hands (single-cursor task). In the first experiment, the two hands were symmetrically perturbed outwards. In the double-cursor task, the participants therefore had to return their hands to the targets, whereas in the single-cursor task no correction was necessary. Within 50 ms, the electromyographic activity showed significantly smaller responses in the single- compared with the double-cursor task. In the second experiment, the perturbation direction of the left hand (inward/outward) was randomized, such that participants could not preplan their response before perturbation onset. Results show that the behavior of the right arm in the one-cursor task depended on online feedback coming from the left arm: the muscular response was modulated within 75 ms based on directionally specific information of the left arm. These results suggest that sensory feedback from one limb can quickly modify the perturbation response of another limb in a task-dependent manner.
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Affiliation(s)
- Mohsen Omrani
- Centre for Neuroscience Studies, Queen’s University, Kingston, Ontario, Canada.
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14
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Pruszynski JA, Scott SH. Optimal feedback control and the long-latency stretch response. Exp Brain Res 2012; 218:341-59. [PMID: 22370742 DOI: 10.1007/s00221-012-3041-8] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/13/2012] [Indexed: 12/27/2022]
Abstract
There has traditionally been a separation between voluntary control processes and the fast feedback responses which follow mechanical perturbations (i.e., stretch "reflexes"). However, a recent theory of motor control, based on optimal control, suggests that voluntary motor behavior involves the sophisticated manipulation of sensory feedback. We have recently proposed that one implication of this theory is that the long-latency stretch "reflex", like voluntary control, should support a rich assortment of behaviors because these two processes are intimately linked through shared neural circuitry including primary motor cortex. In this review, we first describe the basic principles of optimal feedback control related to voluntary motor behavior. We then explore the functional properties of upper-limb stretch responses, with a focus on how the sophistication of the long-latency stretch response rivals voluntary control. And last, we describe the neural circuitry that underlies the long-latency stretch response and detail the evidence that primary motor cortex participates in sophisticated feedback responses to mechanical perturbations.
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15
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Dimitriou M, Franklin DW, Wolpert DM. Task-dependent coordination of rapid bimanual motor responses. J Neurophysiol 2011; 107:890-901. [PMID: 22072514 PMCID: PMC3289469 DOI: 10.1152/jn.00787.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Optimal feedback control postulates that feedback responses depend on the task relevance of any perturbations. We test this prediction in a bimanual task, conceptually similar to balancing a laden tray, in which each hand could be perturbed up or down. Single-limb mechanical perturbations produced long-latency reflex responses ("rapid motor responses") in the contralateral limb of appropriate direction and magnitude to maintain the tray horizontal. During bimanual perturbations, rapid motor responses modulated appropriately depending on the extent to which perturbations affected tray orientation. Specifically, despite receiving the same mechanical perturbation causing muscle stretch, the strongest responses were produced when the contralateral arm was perturbed in the opposite direction (large tray tilt) rather than in the same direction or not perturbed at all. Rapid responses from shortening extensors depended on a nonlinear summation of the sensory information from the arms, with the response to a bimanual same-direction perturbation (orientation maintained) being less than the sum of the component unimanual perturbations (task relevant). We conclude that task-dependent tuning of reflexes can be modulated online within a single trial based on a complex interaction across the arms.
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Affiliation(s)
- Michael Dimitriou
- Computational and Biological Learning Lab, Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
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16
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Global effect on multi-segment physiological tremors due to localized fatiguing contraction. Eur J Appl Physiol 2011; 112:899-910. [DOI: 10.1007/s00421-011-2044-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 06/07/2011] [Indexed: 10/18/2022]
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17
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Kurtzer I, Pruszynski JA, Scott SH. Long-Latency Responses During Reaching Account for the Mechanical Interaction Between the Shoulder and Elbow Joints. J Neurophysiol 2009; 102:3004-15. [DOI: 10.1152/jn.00453.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although considerable research indicates that reaching movements rely on knowledge of the arm's mechanical properties and environment to anticipate and counter predictable loads, far less research has examined whether this degree of sophistication is present for on-line corrections during reaching. Here we examine the R2/3 response to mechanical perturbations (45–100 ms, also called the long-latency reflex), which is highly flexible and includes the fastest possible contribution from primary motor cortex, a key neural substrate for self-initiated action. Torque perturbations were occasionally and unexpectedly applied to the subject's shoulder and/or elbow in the course of performing reaching movements. Critically, these perturbations would evoke different patterns of feedback corrections from a shoulder extensor muscle if it countered only the local shoulder displacement relative to unperturbed motion or accounted for the mechanical interactions between the shoulder and elbow joints and countered the underlying shoulder torque. Our results show that the earliest response (R1: 20–45 ms) reflected local shoulder displacement, whereas the R2/3 response (45–100 ms) reflected knowledge of multijoint dynamics. Moreover, the same pattern of feedback occurred whether the shoulder muscle helped initiate the movement (during its agonist phase) or helped terminate the movement (during its antagonist phase). These results contribute to the accumulating evidence that highly sophisticated feedback control underlies motor behavior and are consistent with a shared neural substrate, such as primary motor cortex, for feedforward and feedback control.
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Affiliation(s)
| | | | - Stephen H. Scott
- Centre for Neuroscience Studies,
- Department of Anatomy and Cell Biology, and
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
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18
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Mutha PK, Sainburg RL. Shared bimanual tasks elicit bimanual reflexes during movement. J Neurophysiol 2009; 102:3142-55. [PMID: 19793874 DOI: 10.1152/jn.91335.2008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous research has suggested distinct predictive and reactive control mechanisms for bimanual movements compared with unimanual motion. Recent studies have extended these findings by demonstrating that movement corrections during bimanual movements might differ depending on whether or not the task is shared between the arms. We hypothesized that corrective responses during shared bimanual tasks recruit bilateral rapid feedback mechanisms such as reflexes. We tested this hypothesis by perturbing one arm as subjects performed uni- and bimanual movements. Movements were made in a virtual-reality environment in which hand position was displayed as a cursor on a screen. During bimanual motion, we provided cursor feedback either independently for each arm (independent-cursor) or such that one cursor was placed at the average location between the arms (shared-cursor). On random trials, we applied a 40 N force pulse to the right arm 100 ms after movement onset. Our results show that while reflex responses were rapidly elicited in the perturbed arm, electromyographic activity remained close to baseline levels in the unperturbed arm during the independent-cursor trials. In contrast, when the cursor was shared between the arms, reflex responses were reduced in the perturbed arm and were rapidly elicited in the unperturbed arm. Our results thus suggest that when both arms contribute to achieving the task goal, reflex responses are bilaterally elicited in response to unilateral perturbations. These results agree with and extend recent suggestions that bimanual feedback control might be modified depending on task context.
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Affiliation(s)
- Pratik K Mutha
- Department of Kinesiology, Pennsylvania State University, University Park, PA 16802, USA
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19
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de Freitas PB, Jaric S. Force coordination in static manipulation tasks performed using standard and non-standard grasping techniques. Exp Brain Res 2009; 194:605-18. [PMID: 19247643 DOI: 10.1007/s00221-009-1738-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 02/07/2009] [Indexed: 11/24/2022]
Affiliation(s)
- Paulo B de Freitas
- Human Performance Lab, Department of Health, Nutrition, and Exercise Sciences, University of Delaware, 547 South College Avenue, Newark, DE 19716, USA
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20
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de Freitas PB, Krishnan V, Jaric S. Force coordination in static manipulation tasks: effects of the change in direction and handedness. Exp Brain Res 2007; 183:487-97. [PMID: 17665176 DOI: 10.1007/s00221-007-1064-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Accepted: 07/04/2007] [Indexed: 10/23/2022]
Abstract
A number of studies have demonstrated high coordination of the hand grip force (GF; normal component of force acting at the digits-object contact area) and load force (LF; tangential component) in a variety of manipulation tasks. The aim of the study was to explore the mainly neglected effect of the change in LF direction and the effect of handedness on GF and LF coordination in bimanual manipulation task. Subjects (N = 14) exerted a bimanual sinusoidal LF pattern against externally fixed handles in trials that gradually changed from unidirectional (LF exerted only in one direction) to fully bidirectional (equal LF peaks in two opposite directions). Despite the gradual change of LF, unidirectional trials demonstrated high indices of force coordination, while in all bidirectional trials, no matter how low and brief LF exertion was in the opposite direction, all indices of GF and LF coordination deteriorated to a considerably lower level. The non-dominant hand demonstrated both a higher directional accuracy of exerting LF and higher GF modulation than the dominant one. We concluded that manipulation tasks performed in a single and two alternating directions may be based on partly distinctive neural control mechanisms, as well as that a switching of muscle synergies required in bidirectional tasks could play a role in the observed phenomenon. Regarding the effect of hand dominance, the recorded advantage of the non-dominant hand could be considered as an addition to the current views of the non-dominant arm/hemisphere specialization in controlling limb position.
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Affiliation(s)
- Paulo Barbosa de Freitas
- Department of Health, Nutrition, and Exercise Sciences, Human Performance Lab, University of Delaware, 547 S. College Av., Newark, DE 19716, USA.
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21
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Witney AG, Wolpert DM. The effect of externally generated loading on predictive grip force modulation. Neurosci Lett 2007; 414:10-5. [PMID: 17289265 PMCID: PMC2635841 DOI: 10.1016/j.neulet.2006.10.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 10/04/2006] [Accepted: 10/12/2006] [Indexed: 11/22/2022]
Abstract
A characteristic of skilled movement is the ability of the CNS to predict the consequences of motor commands. When we lift an object there is an anticipatory increase in grip force that prevents a grasped object from slipping. When an object is pulled from our grasp by an external force, a reflexive modulation in grip force prevents slippage. Here we examine how external perturbations to a grasped object influence anticipatory grip force during object manipulation using a bimanual task, with each hand holding a computer-controlled object. Subjects were instructed to maintain the position of the object held in the right hand. Loading was applied to this restrained object: either self-generated by the action of their left hand or externally generated by a motor. The magnitude of the grip force response to self-generated loading increased after the object was loaded, and the latency of this response remained predictive of load force. This implies that external and self-generated loading increase the anticipatory grip force response. Unlinked trials, where the subject's moved their left hand but no loading was generated on the right-hand object were used to assess the presence of purely predictive control of grip force. External loading soon after self-generated loading maintained an existing predictive response once the linkage between the subject's action and object loading had been removed. However, external loading had no influence as the existing prediction decays. Therefore, the predictive grip force response during object manipulation can be significantly modified by object loading from an external source.
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Affiliation(s)
- Alice G. Witney
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3JN, UK
- Corresponding author.
| | - Daniel M. Wolpert
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
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22
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Aberg M, Ljungberg C, Edin E, Jenmalm P, Millqvist H, Nordh E, Wiberg M. Considerations in evaluating new treatment alternatives following peripheral nerve injuries: A prospective clinical study of methods used to investigate sensory, motor and functional recovery. J Plast Reconstr Aesthet Surg 2007; 60:103-13. [PMID: 17223506 DOI: 10.1016/j.bjps.2006.04.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
The current problem finding reliable and objective methods for evaluating results after peripheral nerve repair is a challenge when introducing new clinical techniques. The aim of this study was to obtain reference material and to evaluate the applicability of different tests used for clinical assessment after peripheral nerve injuries. Fifteen patients with a history of complete median nerve transsection and repair, and 15 healthy volunteers were included. Each subject was investigated using a battery of conventional and new tests for functional, sensory and motor recovery including questionnaires, clinical evaluations, neurophysiological and physiological findings. The results were statistically analysed and comparisons were made within the patient group and between patients and healthy volunteers using a 'per protocol' and an 'intention to treat' approach. Criteria for success were stipulated in order to be able to judge the usefulness of each method. The results showed that 19 of 34 variables, representing six of 16 methods, were not able to fulfil the criteria and were thus questionable for the evaluations of nerve repair in a clinical trial setting. However, 2pd, sensory recovery according to the non-modified British Medical Research Council, sensory neurography, manual muscle test, electromyography, questionnaires (i.e. DASH and the 4 question form) and performance tests (i.e. AMPS and Sollerman's subtests 4 and 8) did fulfil the criteria defined for being useful.
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Affiliation(s)
- M Aberg
- Department of Hand & Plastic Surgery, Umeå University Hospital, Umeå, Sweden.
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23
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Tamburin S, Fiaschi A, Andreoli A, Marani S, Zanette G. Sensorimotor integration to cutaneous afferents in humans: the effect of the size of the receptive field. Exp Brain Res 2005; 167:362-9. [PMID: 16078031 DOI: 10.1007/s00221-005-0041-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Accepted: 04/26/2005] [Indexed: 12/19/2022]
Abstract
Transcranial magnetic stimulation (TMS) can be used to study sensorimotor integration in humans non-invasively. Motor excitability has been found to be inhibited when afferent stimuli are given to a peripheral nerve and precede TMS at interstimulus intervals (ISIs) of 20-50 ms. This phenomenon has been referred to as short-latency afferent inhibition (SAI). To better understand the functional meaning of these phenomena, we examined the effect of the size of the receptive field on SAI to cutaneous afferents in upper-limb sensorimotor areas in humans. We examined the effect of the stimulation of the isolated right first (D1), second (D2) and third finger (D3), the right second and third finger together (D23) and the right first three fingers together (D123) on the amplitude of motor evoked potentials (MEPs) to TMS in hand and forearm muscles. We examined the right abductor pollicis brevis (APB), first dorsal interosseous (FDI), extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles. Digital stimulation preceded TMS at ISIs of 20-50 ms. The effect of D2 stimulation was MEP inhibition (SAI), which was more marked and consistent in APB and FDI muscles than in ECR and FCR muscles. Similarly, D1 and D3 stimulation caused MEP reduction, while no MEP enhancement could be found to single finger stimulation. In contrast, D123 stimulation induced less effective SAI in upper-limb muscles. MEP potentiation was recorded in some muscles to D123 stimulation. A significant difference between D2 and D123 stimulation was found in APB (ISIs = 30-50 ms) and FDI (ISIs = 40-50 ms) muscles, but not in forearm muscles. The effect to D23stimulation on MEP amplitude was intermediate between those to D2 and D123 stimulation. Our data suggest that motor excitability to cutaneous afferents may be influenced by the size of the receptive fields, this effect being the result of increasing convergence between hand afferents in the somatosensory system. These phenomena appear to be topographically arranged across the representation of upper-limb muscles. These findings may help to understand the functional significance of SAI in normal physiology and pathophysiology.
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Affiliation(s)
- Stefano Tamburin
- Department of Neurological Sciences and Vision, Section of Neurological Rehabilitation, University of Verona, Verona, Italy.
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24
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Jaric S, Collins JJ, Marwaha R, Russell E. Interlimb and within limb force coordination in static bimanual manipulation task. Exp Brain Res 2005; 168:88-97. [PMID: 16078026 DOI: 10.1007/s00221-005-0070-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2005] [Accepted: 05/13/2005] [Indexed: 11/29/2022]
Abstract
The aim of the study was to compare the coordination of hand grip (G) and load force (a force that tends to cause slippage of a grasped object; L) in static bimanual manipulation tasks with the same data obtained from the similar dynamic tasks. Based on the previous findings obtained from dynamic tasks, it was hypothesized that an increase in the rate of L change would be predominantly associated with a decrease in the coordination of the within limb forces (coordination of G and L of each hand as assessed through the correlation coefficients), while a decrease in coordination of interlimb forces (between two G and two L) will be less pronounced. Regarding the pattern of modulation of G, the same increase in L frequency was also expected to be associated with a decrease in G gain and an increase in G offset (as assessed by slope and intercept of the regression lines obtained from G to L diagrams, respectively), as well as with an increase in average G/L ratio. Subjects exerted oscillatory isometric L profiles by simultaneous pulling out two handles of an externally fixed device under an exceptionally wide range of L frequencies (0.67-3.33 Hz). The results demonstrated relatively high correlation coefficients between both the interlimb and within limb forces that were only moderately affected under sub-maximal L frequencies. Furthermore, the hypothesized changes in G gain and offset appeared only under the highest L frequency, while the G/L ratio remained unaffected. We conclude that, when compared with the dynamic tasks based on the unconstrained movements of hand-held objects that produce similar pattern of L change, the static manipulation tasks demonstrate a consistent and highly coordinated pattern of bilateral G and L under a wide range of frequencies. However, the neural mechanisms that play a role in the revealed differences need further elucidation.
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Affiliation(s)
- Slobodan Jaric
- Department of Health, Nutrition, and Exercise Sciences, Human Performance Lab, University of Delaware, 547 S. College Av., Newark, DE 19716, USA.
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25
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Abstract
Co-ordinated bi-manual actions form the basis for many everyday motor skills. In this review, the internal model approach to the problem of bi-manual co-ordination is presented. Bi-manual coordinative tasks are often regarded as a hallmark of complex action. They are often associated with object manipulation, whether the holding of a single object between the two hands or holding an object in each hand. However, the task of movement and control is deceptively difficult even when we execute an action with a single hand without holding an object. The simplest voluntary action requires the problems of co-ordination, timing and interaction between neural, muscular and skeletal structures to be overcome. When we are making a movement whilst holding an object, a further requirement is that an internal model is able to predict the dynamics of the object that is being held as well as the dynamics of the motor system. There has been extensive work examining the formation of internal models when acting in novel environments. The majority of studies examine uni-lateral learning of a task generally to the participant's dominant hand. However, many everyday motor tasks are bi-manual, and the existing findings regarding the learning of internal models in uni-manual tasks and their subsequent generalization highlights the complexities that must underlie the formation of bi-manual tasks. Our ability to perform bi-manual tasks raises interesting questions about how internal models are specified for co-ordinative actions, and also for how the motor system learns to represent the properties of objects.
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Affiliation(s)
- Alice G Witney
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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26
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Jaric S, Russell EM, Collins JJ, Marwaha R. Coordination of hand grip and load forces in uni- and bidirectional static force production tasks. Neurosci Lett 2005; 381:51-6. [PMID: 15882789 DOI: 10.1016/j.neulet.2005.01.086] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2005] [Revised: 01/31/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
The purpose of the study was to explore the differences in coordination of grip (G) and load forces (L) in a unidirectional and bidirectional bimanual static force production task. Subjects (N=10) exerted oscillatory isometric L profiles against an externally fixed hand-held device, modulated either in pure tension (unidirectional) or in alternating tension and compression (bidirectional) at a rate of either 1.33 or 2.67 Hz. The unidirectional task revealed a high level of coordination of both the ipsilateral (i.e., G and L of each hand) and contralateral pairs of forces (two Gs and two Ls) as assessed by correlation and stability of force ratios. The bidirectional task demonstrated a low level of inconsistently modulated Gs with respect to the change of L, which resulted in a deteriorated coordination, particularly between the ipsilateral forces. The overall effect of task on the force coordination was higher than the effect of frequency suggesting that the higher frequency of G modulation required in the bidirectional task is not likely to be the main cause of the observed phenomenon. We interpret these differences by a relative simplicity of the control mechanisms of the unidirectional task based on a single synergy of G and L muscles that allows simultaneous coordination of both the ipsilateral and contralateral forces. Due to the switching between two distinctive synergies involving G muscles, the bidirectional task could possess a higher control complexity causing a decoupled coordination of the ipsilateral forces, while retaining the coordination of contralateral forces at a relatively high level.
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Affiliation(s)
- Slobodan Jaric
- Human Performance Laboratory, Department of Health, Nutrition, and Exercise Sciences, University of Delaware, 547 S. College Avenue, Newark, DE 19716, USA.
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27
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Shibuya S, Ohki Y. Cutaneous Inputs Can Activate the Ipsilateral Primary Motor Cortex During Bimanual Sensory-Driven Movements in Humans. J Neurophysiol 2004; 92:3200-9. [PMID: 15115786 DOI: 10.1152/jn.00937.2003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using transcranial magnetic stimulation (TMS), we examined whether sensory input from a finger affects activity of the ipsilateral primary motor cortex (M1) when human subjects hold a virtual object bimanually and whether this ipsilateral activation varies under different contexts. Subjects used both index fingers to hold two plates, which were subjected to unpredictable pulling loads from torque motors. Loads were delivered in a random sequence to either plate or concurrently to both, although the latter occurred most frequently. Finger forces vertical to the plates and surface electromyographs from the first dorsal interosseous muscles were recorded bilaterally during the task. TMS was sometimes applied over the finger area of the left M1 at variable times relative to load onset to examine cortical excitability. Strength of TMS was set around the active motor threshold of the right finger muscle while subjects waited for loading to the handheld plates. When one plate was singly loaded, the M1 contralateral to the loaded finger was activated, causing automatic force increases in the finger. In addition, the ipsilateral M1 was activated during such loading, associated with transient force increases in the contralateral nonloaded finger. Activations in the ipsilateral M1 were also observed during concurrent loading, when activations were stronger than those following single loading of the contralateral plate. Ipsilateral activations weakened when concurrent loading was less frequent. These results suggest interactions between bilateral sensorimotor cortices during bimanual coordinated movements, with strength varying by context.
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Affiliation(s)
- Satoshi Shibuya
- Department of Health and Sports Science, Faculty of Education, Tokyo Gakugei University, Tokyo, Japan
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28
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Ohki Y, Watanabe K. Dependence of Reactive Responses in Human Bimanual Finger Movements on Sensory Feedback and Auditory Cues. J Neurophysiol 2004; 91:1260-70. [PMID: 14602834 DOI: 10.1152/jn.00168.2003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the effects of repetitive experience of feedback events and cue signals on adaptation of bimanual reactive response, both of which can be used to predict load forces on handheld objects. Normal human subjects used bimanual index fingers to hold two plates mounted on separate torque motors. Sensory-driven reactive forces from the fingers were measured during concurrent loading of both plates or isolated loading of the left plate. After repeated experiences of single load conditions, right and left fingers increased normal forces in a coordinated manner during concurrent loading, while the left finger responded almost exclusively during isolated loading of the left plate. However, after switching load conditions from concurrent to isolated load, or vice versa, several trials were needed to adapt to the new condition, as was clearly observed in the dynamic phase of responses from the right finger. Adaptation depends on the number of feedback experiences, and specifically on prediction error, showing intermediate predictions between the two conditions. Thus influences of the previous experiences show similar properties to those observed in self-generated movement, which were reported previously. In addition, auditory cues informing subjects of coming load conditions also partially adapted responses to these conditions. The neuronal center for reactive responses is therefore influenced by both previous experience and cue signals, inducing the appropriate responses for the predicted sensory inputs.
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Affiliation(s)
- Yukari Ohki
- Department of Physiology, Kyorin University School of Medicine, Shinkawa, Mitaka, Tokyo 181-8611, Japan.
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29
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Bracewell RM, Wing AM, Soper HM, Clark KG. Predictive and reactive co-ordination of grip and load forces in bimanual lifting in man. Eur J Neurosci 2003; 18:2396-402. [PMID: 14622202 DOI: 10.1046/j.1460-9568.2003.02944.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the intra- and inter-manual coordination of grip force (GF) and load force (LF) during bimanual lifting and holding of a single object. In a voluntary task involving lifting a predictable load (Experiment 1), we showed scaling of GF to LF generated by either hand, similar to effects seen in previous unimanual studies. Moreover, the GF rates generated by the two hands were correlated. In part this correlation was due to the correlation between the LF rates. However, the GF rates remained correlated when the effects of the correlation in LF rates were partialled out. This novel finding suggests an additional co-ordinative constraint at the level of specification of GFs. As a contrast to the predictable loading in the first experiment, in the second experiment loading was temporally unpredictable and elicited reactive increases in GF. In Experiment 2, the intermanual correlation of GF rates was stronger than in Experiment 1. We speculate that this result reflects greater degrees of co-ordinative constraint at lower levels in the motor control hierarchy.
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Affiliation(s)
- R Martyn Bracewell
- Behavioural Brain Sciences Centre, University of Birmingham, Edgbaston B15 2TT, UK
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30
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Diedrichsen J, Hazeltine E, Nurss WK, Ivry RB. The Role of the Corpus Callosum in the Coupling of Bimanual Isometric Force Pulses. J Neurophysiol 2003; 90:2409-18. [PMID: 14534269 DOI: 10.1152/jn.00250.2003] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Two split-brain patients, a patient with callosal agenesis, and 6 age-matched control participants were tested on a bimanual force production task. The participants produced isometric responses with their index fingers, attempting to match the target force specified by a visual stimulus. On unimanual trials, the stimuli were presented in either the left or right visual field and the response was made with the ipsilateral hand. On bimanual trials, two stimuli were presented, one on each side, and the target forces could be either identical or different. Bimanual responses of the control subjects showed strong evidence of coupling. Forces produced by one hand were influenced by the forces produced by the other hand with positive correlations observed for all target force combinations. These assimilation effects and correlations were greatly attenuated in the acallosal group, with similar results observed for the split-brain patients and participant with callosal agenesis. Furthermore, the processes involved in selecting and planning the two responses occurred independently in the acallosal group; in contrast to the controls, the three acallosal participants exhibited no differences in reaction times or accuracy between bimanual trials in which the two target forces were the same or different. We also found a striking temporal desynchronization of the responses in the split-brain patients, indicating that in this context, temporal coupling is impaired after callosotomy. These results are congruent with the hypothesis that interference related to response selection and planning of bimanual force pulses arises from callosal interactions.
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Affiliation(s)
- Jörn Diedrichsen
- Department of Psychology, University of California, Berkeley, California 94720-5800, USA.
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31
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Abstract
When humans proactively manipulate objects, the applied fingertip forces primarily depend on feedforward, predictive neural control mechanisms that depend on internal representations of the physical properties of the objects. Here we investigate whether predictions of object properties also control fingertip forces that subjects generate reactively. We analyzed fingertip forces reactively supporting grasp stability in a restraining task that engaged two fingers. Each finger contacted a plate mounted on a separate torque motor, and, at unpredictable times, both plates were loaded simultaneously with forces tangential to the plates or just one of the plates was loaded. Thus, the apparatus acted as though the plates were mechanically linked or as though they were two independent objects. In different test series, each with a predominant behavior of the apparatus and with interspersed catch trials, we showed that the reactive responses clearly reflected the predominant behavior of the apparatus. Whether subject performed the task with one hand or bimanually, appropriate reactive fingertip forces developed when predominantly both contact plates were loaded or just one of the plates was loaded. When a finger was unexpectedly loaded during a catch trial, a weak initial reactive response was triggered, but the effective force development was delayed by approximately 100 msec. We conclude that the predicted physical properties of an object not only control fingertip forces during proactive but also in reactive manipulative tasks. Specifically, the automatic reactive responses reflect predictions at the level of individual digits as to the mechanical linkage of items contacted by the fingertips in manipulation.
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32
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Serrien DJ, Wiesendanger M. Bimanual organization of manipulative forces: evidence from erroneous feedforward programming of precision grip. Eur J Neurosci 2001; 13:1825-32. [PMID: 11359534 DOI: 10.1046/j.0953-816x.2001.01548.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The objective of the present study was to investigate grip-load force regulation during a bimanual lifting task with two hand-held objects. Various conditions were included during which the weight of one or both objects was changed in an unpredictable order every fourth trial. Results showed that force control of heavy weight movements preceded by light weight movements was not strongly influenced across trials. Conversely, force responses of light weight movements preceded by heavy weight movements were overestimated due to an augmented degree of grip force. However, successful updating of force output occurred after one trial. Furthermore, bimanual interactions between the grasping forces were observed, suggestive of a coordinative command that assimilated the individual response specifications. The latter also became apparent from a similar grip-load force ratio for both hands when the objects' physical properties had become predictable, independent of the forces that were produced according to the individual weight requirements. These data indicate that the grip-load force ratio is the controlled variable for bimanual manipulative behaviour.
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Affiliation(s)
- D J Serrien
- Department of Neurology, Inselspital, BHH M-133, University of Berne, CH-3010 Berne, Switzerland.
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33
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Iwamura Y, Taoka M, Iriki A. Bilateral activity and callosal connections in the somatosensory cortex. Neuroscientist 2001; 7:419-29. [PMID: 11597101 DOI: 10.1177/107385840100700511] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Earlier studies recording single neuronal activity in the postcentral somatosensory cortex of monkeys converged in suggesting that the bilateral receptive fields were related exclusively to the body midline including the trunk, perioral face, and oral cavity. These neurons were recorded mostly in the rostral part of the gyrus, areas 3b and 1. However, the authors recently found a substantial number of neurons with bilateral receptive fields on extremities, hand/digits, shoulders/arms, or legs/feet in the caudalmost part (areas 2 and 5) of the postcentral gyrus. The authors review these results and discuss functional implications of the bilateral representation in the postcentral somatosensory cortex.
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Affiliation(s)
- Y Iwamura
- Department of Physiology, Toho University School of Medicine, Otaku, Tokyo, Japan.
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Serrien DJ, Wiesendanger M. A higher-order mechanism overrules the automatic grip-load force constraint during bimanual asymmetrical movements. Behav Brain Res 2001; 118:153-60. [PMID: 11164512 DOI: 10.1016/s0166-4328(00)00317-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of the present study was to examine grip-load force regulation during unimanual and bimanual movements. Two protocols were included which manipulated the object's weight and covered distance. Results showed that grip-load ratio was adapted to the task requirements. During unimanual and bimanual symmetrical movements, an increased grip-load force ratio for long versus short amplitude movements as well as for light versus heavy weight movements was noted. These findings could be related to the observed movement speed variations associated with the tasks. During bimanual asymmetrical movements, the grip-load force ratio became comparable for both sides. When transporting different object's weights to constant distances, the grip-load force ratio of light weight movements decreased towards that of heavy weight movements. As movement speed was reduced, it indicates that grasping forces were adapted accordingly. When transporting constant object's weights to different distances, the grip-load force ratio of short amplitude movements increased towards that of long amplitude movements. Since movement speed was decreased, it suggests that a bimanual coordinative command overruled the automatic grip-load coupling. In conclusion, these data show that interlimb coupling induced a rescaling towards a common control structure, leading to similar grasping forces during bimanual movements with dissimilar actions.
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Affiliation(s)
- D J Serrien
- Department of Neurology, University of Berne, Inselspital, BHH M-133, CH-3010 Berne, Switzerland.
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