scholarly journals Comparison of Corticospinal Excitability between Observations of Tonic Contraction and Rhythmic Movement: a TMS Study

2017 ◽  
Vol 6 (0) ◽  
pp. 42-47
Author(s):  
Kanchi Ito ◽  
Yuki Osawa ◽  
Kenta Kaneko ◽  
Yutaka Kikuchi ◽  
Masato Odagaki
Keyword(s):  
Rhythmic Movement ◽  
Tonic Contraction ◽  
Corticospinal Excitability

Premovement Changes in Corticospinal Excitability of the Biceps Brachii are Not Different Between Arm Cycling and an Intensity-Matched Tonic Contraction

Motor Control ◽  
2015 ◽  
Vol 19 (3) ◽  
pp. 223-241 ◽  
Author(s):  
David B. Copithorne ◽  
Davis A. Forman ◽  
Kevin E. Power
Keyword(s):  
Evoked Potentials ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Surface Emg ◽  
Tonic Contraction ◽  
Corticospinal Excitability ◽  
Spinal Motoneuron ◽  
Motoneuron Excitability ◽  
Arm Cycling ◽  
Motor Outputs

The purpose of this study was to determine if supraspinal and/or spinal motoneuron excitability of the biceps brachii were differentially modulated before: 1) arm cycling and 2) an intensity-matched tonic contraction. Surface EMG recordings of motor evoked potentials (MEPs) and cervicomedullary motor evoked potentials (CMEPs) were used to assess supraspinal and spinal motoneuron excitability, respectively. MEP amplitudes were larger and onset latencies shorter, before arm cycling and tonic contraction when compared with rest with no intent to move, but with no difference between motor outputs. CMEP amplitudes and onset latencies remained unchanged before cycling and tonic contraction compared with rest. Premovement enhancement of corticospinal excitability was due to an increase in supraspinal excitability that was not task-dependent. This suggests that a common neural drive is used to initiate both motor outputs with task-dependent changes in neural excitability only being evident once the motor outputs have begun.

Corticospinal excitability of the biceps brachii is higher during arm cycling than an intensity-matched tonic contraction

2014 ◽  
Vol 112 (5) ◽  
pp. 1142-1151 ◽  
Author(s):  
Davis Forman ◽  
Amita Raj ◽  
Duane C. Button ◽  
Kevin E. Power
Keyword(s):  
Evoked Potentials ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Maximum Amplitude ◽  
Elbow Flexion ◽  
Tonic Contraction ◽  
Corticospinal Excitability ◽  
Spinal Motoneuron ◽  
Motoneuron Excitability ◽  
Arm Cycling

Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cycling than an intensity-matched tonic contraction. Supraspinal and spinal motoneuron excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. TMS-induced motor-evoked potentials (MEPs) and TMES-induced cervicomedullary-evoked potentials (CMEPs) were assessed at three separate positions (3, 6, and 12 o'clock relative to a clock face) during arm cycling and an intensity-matched tonic contraction. MEP amplitudes were 7.2 and 8.8% maximum amplitude of the compound muscle action potential (Mmax) larger during arm cycling compared with a tonic contraction at the 3 ( P < 0.001) and 6 o'clock ( P < 0.001) positions, respectively. There was no difference between tasks during elbow extension (12 o'clock). CMEP amplitudes were 5.2% Mmax larger during arm cycling compared with a tonic contraction at the 3 o'clock position ( P < 0.001) with no differences seen at midflexion (6 o'clock) or extension (12 o'clock). The data indicate an increase in the excitability of corticospinal neurons, which ultimately project to biceps brachii during the elbow flexion portion of arm cycling, and increased spinal motoneuron excitability at the onset of elbow flexion during arm cycling. We conclude that supraspinal and spinal motoneuron excitability are phase- and task-dependent.

Corticospinal Excitability Is Lower During Rhythmic Arm Movement Than During Tonic Contraction

2006 ◽  
Vol 95 (2) ◽  
pp. 914-921 ◽  
Author(s):  
Timothy J. Carroll ◽  
Evan R. L. Baldwin ◽  
David F. Collins ◽  
E. Paul Zehr
Keyword(s):  
Motor Cortex ◽  
Neural Control ◽  
Motor Evoked Potentials ◽  
Arm Movement ◽  
Voluntary Contraction ◽  
Tonic Contraction ◽  
H Reflex ◽  
Corticospinal Excitability ◽  
Arm Cycling ◽  
Subcortical Regions

Humans perform rhythmic, locomotor movements with the arms and legs every day. Studies using reflexes to probe the functional role of the CNS suggest that spinal circuits are an important part of the neural control system for rhythmic arm cycling and walking. Here, by studying motor-evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS) of the motor cortex, and H-reflexes induced by electrical stimulation of peripheral nerves, we show a reduction in corticospinal excitability during rhythmic arm movement compared with tonic, voluntary contraction. Responses were compared between arm cycling and tonic contraction at four positions, while participants generated similar levels of muscle activity. Both H-reflexes and MEPs were significantly smaller during arm cycling than during tonic contraction at the midpoint of arm flexion ( F = 13.51, P = 0.006; F = 11.83, P = 0.009). Subthreshold TMS significantly facilitated the FCR H-reflex during tonic contractions, but did not significantly modulate H-reflex amplitude during arm cycling. The data indicate a reduction in the responsiveness of cells constituting the fast, monosynaptic, corticospinal pathway during arm cycling and suggest that the motor cortex may contribute less to motor drive during rhythmic arm movement than during tonic, voluntary contraction. Our results are consistent with the idea that subcortical regions contribute to the control of rhythmic arm movements despite highly developed corticospinal projections to the human upper limb.

Action processing in the motor system: TMS evidence of shared mechanisms in the visual and linguistic modalities.

2018 ◽  
Author(s):  
Claudia Gianelli ◽  
Katharina Kühne ◽  
Silvia Mencaraglia ◽  
Riccardo Dalla Volta
Keyword(s):  
Motor System ◽  
Native Speakers ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Stimulus Presentation ◽  
Corticospinal Excitability ◽  
First Dorsal Interosseous ◽  
Action Processing ◽  
Abductor Digiti Minimi ◽  
Hand Action

In two experiments, we compared the dynamics of corticospinal excitability when processing visually or linguistically presented tool-oriented hand actions in native speakers and sequential bilinguals. In a third experiment we used the same procedure to test non-motor, low-level stimuli, i.e. scrambled images and pseudo-words. Stimuli were presented in sequence: pictures (tool + tool-oriented hand action or their scrambled counterpart) and words (tool noun + tool-action verb or pseudo-words). Experiment 1 presented German linguistic stimuli to native speakers, while Experiment 2 presented English stimuli to non-natives. Experiment 3 tested Italian native speakers. Single-pulse trascranial brain stimulation (spTMS) was applied to the left motor cortex at five different timings: baseline, 200ms after tool/noun onset, 150, 350 and 500ms after hand/verb onset with motor-evoked potentials (MEPs) recorded from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles.We report strong similarities in the dynamics of corticospinal excitability across the visual and linguistic modalities. MEPs’ suppression started as early as 150ms and lasted for the duration of stimulus presentation (500ms). Moreover, we show that this modulation is absent for stimuli with no motor content. Overall, our study supports the notion of a core, overarching system of action semantics shared by different modalities.

Motor cortex disinhibition in normal-pressure hydrocephalus

2012 ◽  
Vol 116 (2) ◽  
pp. 453-459 ◽  
Author(s):  
Andrei V. Chistyakov ◽  
Hava Hafner ◽  
Alon Sinai ◽  
Boris Kaplan ◽  
Menashe Zaaroor
Keyword(s):  
Motor Cortex ◽  
Healthy Volunteers ◽  
Normal Pressure Hydrocephalus ◽  
Close Association ◽  
Motor Evoked Potential ◽  
Normal Pressure ◽  
Corticospinal Excitability ◽  
Conduction Time ◽  
Shunt Placement ◽  
Resting Motor Threshold

Object Previous studies have shown a close association between frontal lobe dysfunction and gait disturbance in idiopathic normal-pressure hydrocephalus (iNPH). A possible mechanism linking these impairments could be a modulation of corticospinal excitability. The aim of this study was 2-fold: 1) to determine whether iNPH affects corticospinal excitability; and 2) to evaluate changes in corticospinal excitability following ventricular shunt placement in relation to clinical outcome. Methods Twenty-three patients with iNPH were examined using single- and paired-pulse transcranial magnetic stimulation of the leg motor area before and 1 month after ventricular shunt surgery. The parameters of corticospinal excitability assessed were the resting motor threshold (rMT), motor evoked potential/M-wave area ratio, central motor conduction time, intracortical facilitation, and short intracortical inhibition (SICI). The results were compared with those obtained in 8 age-matched, healthy volunteers, 19 younger healthy volunteers, and 9 age-matched patients with peripheral neuropathy. Results Significant reduction of the SICI associated with a decrease of the rMT was observed in patients with iNPH at baseline evaluation. Ventricular shunt placement resulted in significant enhancement of the SICI and increase of the rMT in patients who markedly improved, but not in those who failed to improve. Conclusions This study demonstrates that iNPH affects corticospinal excitability, causing disinhibition of the motor cortex. Recovery of corticospinal excitability following ventricular shunt placement is correlated with clinical improvement. These findings support the view that reduced control of motor output, rather than impairment of central motor conduction, is responsible for gait disturbances in patients with iNPH.

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