scholarly journals The effect of electrical stimulation of the corticospinal tract on motor units of the human biceps brachii

2002 ◽  
Vol 544 (1) ◽  
pp. 277-284 ◽  
Author(s):  
Nicolas T. Petersen ◽  
Janet L. Taylor ◽  
Simon C. Gandevia
Keyword(s):  
Electrical Stimulation ◽  
Corticospinal Tract ◽  
Biceps Brachii ◽  
Motor Units ◽  
Stimulation Of

Increased corticospinal excitability prior to arm cycling is due to enhanced supraspinal but not spinal motoneurone excitability

2013 ◽  
Vol 38 (11) ◽  
pp. 1154-1161 ◽  
Author(s):  
Kevin E. Power ◽  
David B. Copithorne
Keyword(s):  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Quiescent State ◽  
M Wave ◽  
Arm Cycling ◽  
Intention To Move ◽  
Stimulation Of

Human studies have not assessed supraspinal or spinal motoneurone excitability in the quiescent state prior to a rhythmic and alternating cyclical motor output. The purpose of the current study was to determine whether supraspinal and (or) spinal motoneurone excitability was modulated in humans prior to arm cycling when compared with rest with no intention to move. We hypothesized that corticospinal excitability would be enhanced prior to arm cycling due, in part, to increased spinal motoneurone excitability. Supraspinal and spinal motoneurone excitability were assessed via transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid stimulation of the corticospinal tract, respectively. Surface electromyography recordings of TMS motor evoked potentials (MEPs) and cervicomedullary MEPs (CMEPs) were made from the relaxed biceps brachii muscle prior to rhythmic arm cycling and at rest with no intention to move. The amplitude of the MEPs was greater (mean increase: +9.8% of maximal M wave; p = 0.006) and their onset latencies were shorter (mean decrease: –1.5 ms; p < 0.05) prior to cycling when compared with rest. The amplitudes of the CMEPs at any of 3 stimulation intensities were not different between conditions. We conclude that premovement enhancement of corticospinal excitability is greater prior to arm cycling than at rest because of increases in supraspinal but not spinal motoneurone excitability.

scholarly journals Phasic action of the tensor muscle modulates the calling song in cicadas

1996 ◽  
Vol 199 (7) ◽  
pp. 1535-1544
Author(s):  
P Fonseca ◽  
R Hennig
Keyword(s):  
Electrical Stimulation ◽  
Sound Production ◽  
Time Window ◽  
Time Lag ◽  
Motor Units ◽  
Pulse Amplitude ◽  
Time Correlation ◽  
Calling Song ◽  
Sound Pulse ◽  
Stimulation Of

The effect of tensor muscle contraction on sound production by the tymbal was investigated in three species of cicadas (Tettigetta josei, Tettigetta argentata and Tympanistalna gastrica). All species showed a strict time correlation between the activity of the tymbal motoneurone and the discharge of motor units in the tensor nerve during the calling song. Lesion of the tensor nerve abolished the amplitude modulation of the calling song, but this modulation was restored by electrical stimulation of the tensor nerve or by mechanically pushing the tensor sclerite. Electrical stimulation of the tensor nerve at frequencies higher than 30&shy;40 Hz changed the sound amplitude. In Tett. josei and Tett. argentata there was a gradual increase in sound amplitude with increasing frequency of tensor nerve stimulation, while in Tymp. gastrica there was a sudden reduction in sound amplitude at stimulation frequencies higher than 30 Hz. This contrasting effect in Tymp. gastrica was due to a bistable tymbal frame. Changes in sound pulse amplitude were positively correlated with changes in the time lag measured from tymbal motoneurone stimulation to the sound pulse. The tensor muscle acted phasically because electrical stimulation of the tensor nerve during a time window (0&shy;10 ms) before electrical stimulation of the tymbal motoneurone was most effective in eliciting amplitude modulations. In all species, the tensor muscle action visibly changed the shape of the tymbal. Despite the opposite effects of the tensor muscle on sound pulse amplitude observed between Tettigetta and Tympanistalna species, the tensor muscle of both acts by modulating the shape of the tymbal, which changes the force required for the tymbal muscle to buckle the tymbal.

scholarly journals Modulation of motor unit activity in biceps brachii by neuromuscular electrical stimulation applied to the contralateral arm

2015 ◽  
Vol 118 (12) ◽  
pp. 1544-1552 ◽  
Author(s):  
Ioannis G. Amiridis ◽  
Diba Mani ◽  
Awad Almuklass ◽  
Boris Matkowski ◽  
Jeffrey R. Gould ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Motor Unit ◽  
Unit Activity ◽  
Pulse Width ◽  
Biceps Brachii ◽  
Neuromuscular Electrical Stimulation ◽  
Motor Units ◽  
Elbow Flexors ◽  
Discharge Characteristics ◽  
Low Threshold

The purpose of the study was to determine the influence of neuromuscular electrical stimulation (NMES) current intensity and pulse width applied to the right elbow flexors on the discharge characteristics of motor units in the left biceps brachii. Three NMES current intensities were applied for 5 s with either narrow (0.2 ms) or wide (1 ms) stimulus pulses: one at 80% of motor threshold and two that evoked contractions at either ∼10% or ∼20% of maximal voluntary contraction (MVC) force. The discharge times of 28 low-threshold (0.4–21.6% MVC force) and 16 high-threshold (31.7–56.3% MVC force) motor units in the short head of biceps brachii were determined before, during, and after NMES. NMES elicited two main effects: one involved transient deflections in the left-arm force at the onset and offset of NMES and the other consisted of nonuniform modulation of motor unit activity. The force deflections, which were influenced by NMES current intensity and pulse width, were observed only when low-threshold motor units were tracked. NMES did not significantly influence the discharge characteristics of tracked single-threshold motor units. However, a qualitative analysis indicated that there was an increase in the number of unique waveforms detected during and after NMES. The findings indicate that activity of motor units in the left elbow flexors can be modulated by NMES current and pulse width applied to right elbow flexors, but the effects are not distributed uniformly to the involved motor units.

Spatial distribution of motor units recruited during electrical stimulation of the quadriceps muscle versus the femoral nerve

2013 ◽  
Vol 48 (5) ◽  
pp. 752-761 ◽  
Author(s):  
Javier Rodriguez-Falces ◽  
Nicola A. Maffiuletti ◽  
Nicolas Place
Keyword(s):  
Spatial Distribution ◽  
Electrical Stimulation ◽  
Femoral Nerve ◽  
Motor Units ◽  
Quadriceps Muscle ◽  
Stimulation Of

Electrical stimulation of cortex improves corticospinal tract tracing in rat spinal cord using manganese-enhanced MRI

2006 ◽  
Vol 156 (1-2) ◽  
pp. 17-22 ◽  
Author(s):  
Mehmet Bilgen ◽  
Warner Peng ◽  
Baraa Al-Hafez ◽  
Numa Dancause ◽  
Yong-Yue He ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Corticospinal Tract ◽  
Rat Spinal Cord ◽  
Tract Tracing ◽  
Enhanced Mri ◽  
Manganese Enhanced Mri ◽  
Stimulation Of
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