Comparative analysis of motor unit action potentials of the medial gastrocnemius muscle in cats and rats

Krutki, Piotr; Ciechanowicz, Iwona; Celichowski, Jan; Cywińska-Wasilewska, Grażyna

doi:10.1016/j.jelekin.2007.02.013

Cited by 8 publications

(4 citation statements)

References 26 publications

(37 reference statements)

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“…Because the increase of amplitude was observed mainly for S MUs, we concluded that motor neurons of these MUs were the most active in reinnervation. The amplitude of MUAP correlates with MU force, and the MU forces increased only for S MUs in the ALS III group. At the same time, twitch forces as well as action potential amplitudes of FF MUs were lower in the ALS animals as compared with controls, also suggesting that the strongest FF MUs degenerated during disease development.…”

Section: Discussionmentioning

confidence: 88%

Changes in motor unit properties in SOD1 (G93A) rats

2014

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Section: Discussionmentioning

confidence: 88%

Changes in motor unit properties in SOD1 (G93A) rats

2014

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“…The following MUAP parameters were measured: (1) amplitude (from the minimum to the maximum of an MUAP recording); (2) total duration (from the beginning to the end of an MUAP recording); (3) peak‐to‐peak time (between the minimum and maximum deflections of a MUAP recording); (4) number of turns (points of change in direction of a potential with at least 50‐µV difference); and (5) number of phases (number of isoelectric line crossings plus 1) (Fig. C) …”

Section: Methodsmentioning

confidence: 99%

Force regulation and electrical properties of motor units in overloaded muscle

et al. 2015

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“…It is relative amplitude that exhibits the robust recruitment effect, which suggests that it is primarily influenced by factors intrinsic to the motor unit, such as the number of fibers it contains (Henneman and Mendell 1981) or the cross-sectional area of individual fibers (Goldberg and Derfler 1977). The precise effects of intrinsic and extrinsic factors in determining EMG spike amplitude have been extensively discussed and modeled (e.g., Akaboshi et al 2000; Clamann and Robinson 1985; Ertas et al 1995; Fuglevand et al 1993; Keenan and Valero-Cuevas 2007; Keenan et al 2006; Krutki et al 2008; Nandedkar et al 1988a,b; Stålberg and Karlsson 2001; Yao et al 2000). In general terms, it appears that intrinsic factors are likely to be particularly dominant in small muscles, especially if they contain only one type of muscle fiber, as appears to be the case for the retractor bulbi muscle (Alvarado et al 1967; Crandall et al 1981; Gurahian and Goldberg 1987; Lennerstrand 1974).…”

Section: Discussionmentioning

confidence: 99%

Recruitment in Retractor Bulbi Muscle During Eyeblink Conditioning: EMG Analysis and Common-Drive Model

Lepora

Porrill

Yeo

et al. 2009

Journal of Neurophysiology

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To analyze properly the role of the cerebellum in classical conditioning of the eyeblink and nictitating membrane (NM) response, the control of conditioned response dynamics must be better understood. Previous studies have suggested that the control signal is linearly related to the CR as a result of recruitment within the accessory abducens motoneuron pool, which acts to linearize retractor bulbi muscle and NM response mechanics. Here we investigate possible recruitment mechanisms. Data came from simultaneous recordings of NM position and multiunit electromyographic (EMG) activity from the retractor bulbi muscle of rabbits during eyeblink conditioning, in which tone and periocular shock act as conditional and unconditional stimuli, respectively. Action potentials (spikes) were extracted and classified by amplitude. Firing rates of spikes with different amplitudes were analyzed with respect to NM response temporal profiles and total EMG spike firing rate. Four main regularities were revealed and quantified: 1) spike amplitude increased with response amplitude; 2) smaller spikes always appeared before larger spikes; 3) subsequent firing rates covaried for spikes of different amplitude, with smaller spikes always firing at higher rates than larger ones; and 4) firing-rate profiles were approximately Gaussian for all amplitudes. These regularities suggest that recruitment does take place in the retractor bulbi muscle during conditioned NM responses and that all motoneurons receive the same command signal (common-drive hypothesis). To test this hypothesis, a model of the motoneuron pool was constructed in which motoneurons had a range of intrinsic thresholds distributed exponentially, with threshold linearly related to EMG spike amplitude. Each neuron received the same input signal as required by the common-drive assumption. This simple model reproduced the main features of the data, suggesting that conditioned NM responses are controlled by a common-drive mechanism that enables simple commands to determine response topography in a linear fashion.

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Comparative analysis of motor unit action potentials of the medial gastrocnemius muscle in cats and rats

Cited by 8 publications

References 26 publications

Changes in motor unit properties in SOD1 (G93A) rats

Changes in motor unit properties in SOD1 (G93A) rats

Force regulation and electrical properties of motor units in overloaded muscle

Recruitment in Retractor Bulbi Muscle During Eyeblink Conditioning: EMG Analysis and Common-Drive Model

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