Reduction of Cortico-spinal Excitability by Transcranial Magnetic Stimulation at Predictable Timing

Acetaminophen (ACT) facilitates the inhibition of voltage-gated calcium and sodium currents, which may effect cortico-spinal excitability. Twelve subjects ingested acetaminophen or a placebo and underwent transcranial magnetic stimulation to assess the motor evoked potential (MEP), and cortical silent period (CSP). ACT significantly increased MEP response (P > 0.05) but had no effect on CSP (P > 0.05). This indicates that ACT increases MEP and should be controlled for in studies where these measures are of interest.

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An Increase in Cortical Excitability with No Change in Spinal Excitability during Motor Imagery

Perceptual and Motor Skills ◽

10.2466/pms.1996.83.1.288 ◽

1996 ◽

Vol 83 (1) ◽

pp. 288-290 ◽

Cited By ~ 56

Author(s):

Susumu Yahagi ◽

Kuniyoshi Shimura ◽

Tatsuya Kasai

Keyword(s):

Transcranial Magnetic Stimulation ◽

Evoked Potentials ◽

Motor Imagery ◽

Magnetic Stimulation ◽

Cortical Excitability ◽

Motor Evoked Potentials ◽

Emg Activity ◽

Electrical Stimuli ◽

Spinal Excitability ◽

Flexor Carpi Radialis Muscle

During motor imagery, to estimate changes in excitability of flexor carpi radialis muscle motoneurons of the spinal and cortical levels, electrical stimuli for recording H-reflex and transcranial magnetic stimulation (TMS) for recording motor evoked potentials (MEPs) were used. In the absence of movement or detectable EMG activity during motor magery, there was an increase in cortical excitability with no change in spinal excitability

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Repetitive transcranial magnetic stimulation on the modulation of cortical and spinal cord excitability in individuals with spinal cord injury

Restorative Neurology and Neuroscience ◽

10.3233/rnn-211167 ◽

2021 ◽

pp. 1-11

Author(s):

Thyciane Mendonça ◽

Rodrigo Brito ◽

Plínio Luna ◽

Mayara Campêlo ◽

Lívia Shirahige ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Cortical Excitability ◽

Repetitive Transcranial Magnetic Stimulation ◽

Sham Stimulation ◽

Resting Motor Threshold ◽

Cord Injury ◽

Spinal Excitability

Background: Repetitive transcranial magnetic stimulation (rTMS) has been applied for modulating cortical excitability and treating spasticity in neurological lesions. However, it is unclear which rTMS frequency is most effective in modulating cortical and spinal excitability in incomplete spinal cord injury (SCI). Objective: To evaluate electrophysiological and clinical repercussions of rTMS compared to sham stimulation when applied to the primary motor cortex (M1) in individuals with incomplete SCI. Methods: A total of 11 subjects (35±12 years) underwent three experimental sessions of rTMS (10 Hz, 1 Hz and sham stimulation) in a randomized order at 90%intensity of the resting motor threshold and interspersed by a seven-day interval between sessions. The following outcome measures were evaluated: M1 and spinal cord excitability and spasticity in the moments before (baseline), immediately after (T0), 30 (T30) and 60 (T60) minutes after rTMS. M1 excitability was obtained through the motor evoked potential (MEP); spinal cord excitability by the Hoffman reflex (H-reflex) and homosynaptic depression (HD); and spasticity by the modified Ashworth scale (MAS). Results: A significant increase in cortical excitability was observed in subjects submitted to 10 Hz rTMS at the T0 moment when compared to sham stimulation (p = 0.008); this increase was also significant at T0 (p = 0.009), T30 (p = 0.005) and T60 (p = 0.005) moments when compared to the baseline condition. No significant differences were observed after the 10 Hz rTMS on spinal excitability or on spasticity. No inter-group differences were detected, or in the time after application of 1 Hz rTMS, or after sham stimulation for any of the assessed outcomes. Conclusions: High-frequency rTMS applied to M1 was able to promote increased cortical excitability in individuals with incomplete SCI for at least 60 minutes; however, it did not modify spinal excitability or spasticity.

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Hysteresis Effects of Cortico-Spinal Excitability during Transcranial Magnetic Stimulation

Frontiers in Computational Neuroscience ◽

10.3389/conf.neuro.10.2009.14.124 ◽

2009 ◽

Vol 3 ◽

Author(s):

Ziemann Ulf

Keyword(s):

Transcranial Magnetic Stimulation ◽

Magnetic Stimulation ◽

Spinal Excitability

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Cadence-dependent changes in corticospinal excitability of the biceps brachii during arm cycling

Journal of Neurophysiology ◽

10.1152/jn.00418.2015 ◽

2015 ◽

Vol 114 (4) ◽

pp. 2285-2294 ◽

Cited By ~ 22

Author(s):

Davis A. Forman ◽

Devin T. G. Philpott ◽

Duane C. Button ◽

Kevin E. Power

Keyword(s):

Electrical Stimulation ◽

Transcranial Magnetic Stimulation ◽

Evoked Potentials ◽

Magnetic Stimulation ◽

Biceps Brachii ◽

Elbow Flexion ◽

Elbow Extension ◽

Arm Cycling ◽

Spinal Excitability ◽

Stimulation Of

This is the first study to report the influence of different cadences on the modulation of supraspinal and spinal excitability during arm cycling. Supraspinal and spinal excitability were assessed using transcranial magnetic stimulation of the motor cortex and transmastoid electrical stimulation of the corticospinal tract, respectively. Transcranial magnetic stimulation-induced motor evoked potentials and transmastoid electrical stimulation-induced cervicomedullary evoked potentials (CMEPs) were recorded from the biceps brachii at two separate positions corresponding to elbow flexion and extension (6 and 12 o'clock relative to a clock face, respectively) while arm cycling at 30, 60 and 90 rpm. Motor evoked potential amplitudes increased significantly as cadence increased during both elbow flexion ( P < 0.001) and extension ( P = 0.027). CMEP amplitudes also increased with cadence during elbow flexion ( P < 0.01); however, the opposite occurred during elbow extension (i.e., decreased CMEP amplitude; P = 0.01). The data indicate an overall increase in the excitability of corticospinal neurons which ultimately project to biceps brachii throughout arm cycling as cadence increased. Conversely, changes in spinal excitability as cadence increased were phase dependent (i.e., increased during elbow flexion and decreased during elbow extension). Phase- and cadence-dependent changes in spinal excitability are suggested to be mediated via changes in the balance of excitatory and inhibitory synaptic input to the motor pool, as opposed to changes in the intrinsic properties of spinal motoneurons.

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