Neural Control of Hand Muscles During Prehension

Johnston, Jamie A.; Winges, Sara A.; Santello, Marco

doi:10.1007/978-0-387-77064-2_31

Cited by 20 publications

(24 citation statements)

References 69 publications

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“…These features are in accord with the concept of a common, frequency-modulated neural input to the MN population (De Luca and Erim 1994;see also DeLuca and Contessa 2012;De Luca and Erim 2002;Farina et al 2013;Farmer et al 1993;Johnston et al 2005Johnston et al , 2009Laine and Bailey 2011;Marsden et al 1999;Rose and Knight 2011;Semmler et al 1997;Winges et al 2008). As indicated by our analyses, the strength of the modulation synchrony is not related to the force level and the frequency of the force variations or, equivalently, to the level and frequency of the oscillatory common input.…”

Section: Mu Firing Modulations and Underlying Neural Inputsupporting

confidence: 87%

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions

Erimaki

Agapaki

Christakos

2013

Journal of Neurophysiology

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Section: Mu Firing Modulations and Underlying Neural Inputsupporting

confidence: 87%

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions

Erimaki

Agapaki

Christakos

2013

Journal of Neurophysiology

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“…Therefore we hypothesized that subjects would employ significantly different digit forces as a function of wrist angle. Preliminary results of this study have been published as an abstract [18] and as part of a book chapter [12]. …”

mentioning

confidence: 99%

“…Previous studies of single motor units of hand muscles have revealed correlated neural drive to motor neuron pools of intrinsic [16] and extrinsic [9,12,13,14,24,25] hand muscles as well as to both sets of hand muscles [26]. Analysis of correlated variability in multi-unit EMG amplitude of hand muscles has further revealed diffused, broad co-activation of intrinsic and extrinsic hand muscles [19].…”

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confidence: 99%

Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping

Johnston¹,

Bobich²,

Santello³

2010

Neuroscience Letters

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Fingertip forces result from activation of muscles that cross the wrist and muscles whose origins and insertions reside within the hand (extrinsic and intrinsic hand muscles, respectively). Thus, tasks that involve changes in wrist angle affect the moment arm and length, hence the force-producing capabilities, of extrinsic muscles only. If a grasping task requires the exertion of constant fingertip forces, the Central Nervous System (CNS) may respond to changes in wrist angle by modulating the neural drive to extrinsic or intrinsic muscles only or by co-activating both sets of muscles. To distinguish between these scenarios, we recorded electromyographic (EMG) activity of intrinsic and extrinsic muscles of the thumb and index finger as a function of wrist angle during a two-digit object hold task. We hypothesized that changes in wrist angle would elicit EMG amplitude modulation of the extrinsic and intrinsic hand muscles. In one experimental condition we asked subjects to exert the same digit forces at each wrist angle, whereas in a second condition subjects could choose digit forces for holding the object. EMG activity was significantly modulated in both extrinsic and intrinsic muscles as a function of wrist angle (both p < 0.05) but only for the constant force condition. Furthermore, EMG modulation resulted from uniform scaling of EMG amplitude across all muscles. We conclude that the CNS controlled both extrinsic and intrinsic muscles as a muscle synergy. These findings are discussed within the theoretical frameworks of synergies and common neural input across motor nuclei of hand muscles.

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“…In addition to sensory loss, the changes in somatosensory feedback due to varied wrist posture impacts muscle coherence across intrinsic and extrinsic muscles [31]. Furthermore, extrinsic muscles were found to have a stronger coherence than the intrinsic muscles [32,33]. The lower coherence has been interpreted as a benefit for intrinsic muscle function [34].…”

Section: Discussionmentioning

confidence: 99%

Effects of Carpal Tunnel Syndrome on Force Coordination and Muscle Coherence during Precision Pinch

Xiu

et al. 2017

J. Med. Biol. Eng.

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Carpal tunnel syndrome (CTS), caused by entrapment of the median nerve in the carpal tunnel, impairs hand function including dexterous manipulation. The purpose of this study was to investigate the effects of CTS on force coordination and muscle coherence during low-intensity sustained precision pinch while the wrist assumed different postures. Twenty subjects (10 CTS patients and 10 asymptomatic controls) participated in this study. An instrumented pinch device was used to measure the thumb and index finger forces while simultaneously collecting surface electromyographic activities of the abductor pollicis brevis (APB) and first dorsal interosseous (FDI) muscles. Subjects performed a sustained precision pinch at 10% maximum pinch force for 15 sec with the wrist stabilized at 30° extension, neutral, or 30° flexion using customized splints. The force discrepancy and the force coordination angle between the thumb and index finger forces were calculated, as well as the β-band (15-30 Hz) coherence between APB and FDI. The index finger applied greater force than the thumb (p < 0.05); this force discrepancy was increased with wrist flexion (p < 0.05), but was not affected by CTS (p > 0.05). The directional force coordination was not significantly affected by wrist posture or CTS (p > 0.05). In general, digit force coordination during precision pinch seems to be sensitive to wrist flexion, but is not affected by CTS. The β-band muscular coherence was increased by wrist flexion for CTS patients (p < 0.05), which could be a compensatory mechanism for the flexion-induced exacerbation of CTS symptoms. This study demonstrates that wrist flexion negatively influences muscle and force coordination in CTS patients supporting the avoidance of flexion posture for symptom exacerbation and functional performance.

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Neural Control of Hand Muscles During Prehension

Cited by 20 publications

References 69 publications

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions

Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping

Effects of Carpal Tunnel Syndrome on Force Coordination and Muscle Coherence during Precision Pinch

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