Motoneuron double discharges: only one or two different entities?

Kudina, Lydia P.; Andreeva, Regina E.

doi:10.3389/fncel.2013.00075

Cited by 19 publications

(19 citation statements)

References 36 publications

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“…High-frequency discharges have also been recorded from single motor units during locomotion in the rat (24) and during rapid corrective movements performed during locomotion in humans (28). Doublet discharges at the onset of fast contractions have been suggested to enable rapid force development and thus are probably functionally relevant (16,46). The addition of a high-frequency doublet, similar to a motor unit doublet, at the onset of slow, constant-frequency electrical stimulation can also augment subsequent force production for up to several seconds (i.e., catchlike property) (22,63).…”

Section: Discussionmentioning

confidence: 99%

“…During voluntary contractions, skeletal motor units can be activated to discharge briefly at very high frequencies (interstimulus interval, ISI Ͻ 20 ms) (5,14,67). The presence of doublet discharges at the onset of ballistic contractions suggests that doublet potentiation may in fact be utilized to facilitate rapid force generation during volitional contractions (16,46).…”

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confidence: 99%

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Doublet potentiation in the triceps surae is limited by series compliance and dynamic fascicle behavior

Mayfield

Lichtwark

Cronin

et al. 2015

Journal of Applied Physiology

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Activation of skeletal muscle twice in quick succession results in nonlinear force summation (i.e., doublet potentiation). The force contributed by a second activation is typically of augmented amplitude, longer in duration, and generated at a greater rate. The purpose of this study was to examine force summation in a muscle attached to a compliant tendon, where considerable internal shortening occurs during a fixed-end contraction. The triceps surae of 21 (Experiment 1) and 9 (Experiment 2) young adults were maximally activated with doublet stimulation of different interstimulus intervals (ISIs) (5-100 ms) at several muscle lengths. Ultrasound images acquired from lateral gastrocnemius and soleus muscles allowed quantification of dynamic fascicle behavior. Force summation was muscle length dependent. Force augmentation was limited to a short muscle length. Lateral gastrocnemius and soleus fascicles underwent large amounts of active shortening and achieved high velocities in response to doublet stimulation, dynamics unfavorable for force production. Summation amplitude and the sensitivity of summation to ISI were dramatically depressed in the triceps surae after comparison to muscles with less fixed-end compliance. We propose that the internal shortening permitted by high series compliance limited force augmentation by offsetting and/or interfering with activation and cross-bridge processes driving augmentation. High series compliance may also reduce the sensitivity of the summated response to ISI, an assertion supported by predictions from a Hill-type muscle model. These muscles may exhibit greater force augmentation during more accustomed stretch-shorten tasks (i.e., hopping), where the compliance of the Achilles tendon actually enables near-isometric fascicle behavior.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Doublet potentiation in the triceps surae is limited by series compliance and dynamic fascicle behavior

Mayfield

Lichtwark

Cronin

et al. 2015

Journal of Applied Physiology

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“…Nonetheless, the doublet pattern is not specific for PD and can be seen under other normal and pathological conditions. For example, doublets are seen in humans at the onset of strong and ballistic movements (35), during whole-body heating (36), and after dynamic training (37). Doublets are common in neuropathies (38) and amyotrophic lateral sclerosis (39).…”

Section: Emg As a Potential Early Marker For Pdmentioning

confidence: 99%

Non-Linear EMG Parameters for Differential and Early Diagnostics of Parkinson’s Disease

Meigal¹,

Rissanen²,

Tarvainen³

et al. 2013

Front. Neurol.

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The pre-clinical diagnostics is essential for management of Parkinson’s disease (PD). Although PD has been studied intensively in the last decades, the pre-clinical indicators of that motor disorder have yet to be established. Several approaches were proposed but the definitive method is still lacking. Here we report on the non-linear characteristics of surface electromyogram (sEMG) and tremor acceleration as a possible diagnostic tool, and, in prospective, as a predictor for PD. Following this approach we calculated such non-linear parameters of sEMG and accelerometer signal as correlation dimension, entropy, and determinism. We found that the non-linear parameters allowed discriminating some 85% of healthy controls from PD patients. Thus, this approach offers considerable potential for developing sEMG-based method for pre-clinical diagnostics of PD. However, non-linear parameters proved to be more reliable for the shaking form of PD, while diagnostics of the rigid form of PD using EMG remains an open question.

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“…From this reason, doublets are considered as a special strategy of the central nervous system, which improves efficiency of a motor task requiring large force especially at early stage of muscle contraction (Garland and Griffin, 1999; Kudina and Andreeva, 2013). …”

Section: Introductionmentioning

confidence: 99%

Physiological consequences of doublet discharges on motoneuronal firing and motor unit force

Mrówczyński

Celichowski

Raikova

et al. 2015

Front. Cell. Neurosci.

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The double discharges are observed at the onset of contractions of mammalian motor units (MUs), especially during their recruitment to strong or fast movements. Doublets lead to MU force increase and improve ability of muscles to maintain high force during prolonged contractions. In this review we discuss an ability to produce doublets by fast and slow motoneurons (MNs), their influence on the course of action potential afterhyperpolarization (AHP) as well as its role in modulation of the initial stage of the firing pattern of MNs. In conclusion, a generation of doublets is an important strategy of motor control, responsible for fitting the motoneuronal firing rate to the optimal for MUs at the start of their contraction, necessary for increment of muscle force.

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Motoneuron double discharges: only one or two different entities?

Cited by 19 publications

References 36 publications

Doublet potentiation in the triceps surae is limited by series compliance and dynamic fascicle behavior

Doublet potentiation in the triceps surae is limited by series compliance and dynamic fascicle behavior

Non-Linear EMG Parameters for Differential and Early Diagnostics of Parkinson’s Disease

Physiological consequences of doublet discharges on motoneuronal firing and motor unit force

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