1 Hz Repetitive Transcranial Magnetic Stimulation of the Primary Motor Cortex: Impact on Excitability and Task Performance in Healthy Subjects

2020 ◽  
Vol 81 (02) ◽  
pp. 147-154 ◽  
Author(s):  
Melina Engelhardt ◽  
Thomas Picht
Keyword(s):  
Motor Cortex ◽  
Healthy Subjects ◽  
Grip Force ◽  
Silent Period ◽  
Small Sample ◽  
Hemispheric Dominance ◽  
Finger Tapping ◽  
Cortical Silent Period ◽  
Brain Areas ◽  
Resting Motor Threshold

Abstract Objective Neuronavigated repetitive transcranial stimulation (rTMS) at a frequency of 1 Hz was shown to reduce excitability in underlying brain areas while increasing excitability in the opposite hemisphere. In stroke patients, this principle is used to normalize activity between the lesioned and healthy hemispheres and to facilitate rehabilitation. However, standardization is lacking in applied protocols, and there is a poor understanding of the underlying physiologic mechanisms. Furthermore, the influence of hemispheric dominance on the intervention has not been studied before. A systematic evaluation of the effects in healthy subjects would deepen the understanding of these mechanisms and offer insights into ways to improve the intervention. Methods Twenty healthy subjects underwent five 15-minute sessions of neuronavigated rTMS or sham stimulation over their dominant or nondominant motor cortex. Dominance was assessed with the Edinburgh Handedness Inventory. Changes in both hemispheres were measured using behavioral parameters (finger tapping, grip force, and finger dexterity) and TMS measures (resting motor threshold, recruitment curve, motor area, and cortical silent period). Results All subjects tolerated the stimulation well. A pronounced improvement was noted in finger tapping scores over the nonstimulated hemisphere as well as a nonsignificant reduction of the cortical silent period in the stimulated hemisphere, indicating a differential effect of the rTMS on both hemispheres. Grip force remained at the baseline level in the rTMS group while decreasing in the sham group, suggesting the rTMS counterbalanced the effects of fatigue. Lastly, dominance did not influence any of the observed effects. Conclusions This study shows the capability of the applied low-frequency rTMS protocol to modify excitability of underlying brain areas as well as the contralateral hemisphere. It also highlights the need for a better understanding of underlying mechanisms and the identification of predictors for responsiveness to rTMS. However, results should be interpreted with caution because of the small sample size.

scholarly journals Evaluation of the Cortical Silent Period of the Laryngeal Motor Cortex in Healthy Individuals

2017 ◽  
Vol 11 ◽  
Author(s):  
Mo Chen ◽  
Rebekah L. S. Summers ◽  
George S. Goding ◽  
Sharyl Samargia ◽  
Christy L. Ludlow ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Silent Period ◽  
Healthy Individuals ◽  
Cortical Silent Period

Abstract 2806: Does Motor Cortex Activity Predict Motor Recovery? An fMRI Study of Subacute Lacunar Stroke

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Assia Jaillard ◽  
Chantal Delon martin ◽  
Leeanne Carey ◽  
Laurent Lalamalle ◽  
Marc J Hommel ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Recovery ◽  
Small Sample ◽  
Stroke Onset ◽  
Stroke Recovery ◽  
Finger Tapping ◽  
Lacunar Stroke ◽  
Related Activity ◽  
Recovery Score

Background: While primary motor cortex (M1) has been demonstrated to be crucial for motor recovery in a recent meta-analysis including fMRI and TMS studies, other functional neuroimaging studies have found that activity in a broader sensorimotor cortical network correlate with motor recovery. The heterogeneity of stroke lesions and the small sample size characterizing many studies could account for these discrepancies. Hypothesis : The strength of task-related activity in primary motor cortex predicts motor recovery in a clinically homogenous population of acute lacunar stroke patients. Methods: We used fMRI to investigate the neural mechanisms of stroke recovery. We studied 18 stroke patient (4 females, 14 males) after their first single lacunar stroke (7 right , 11 left hemisphere). The lesions caused pure hemiparesia one week after stroke onset (mean 7.2 days; range 2 -15). Lesions were limited to the deep territory of the anterior choroid artery, involving the corticospinal tract at the level of the internal capsule or the corona radiata ( Figure 1 ). Patients were matched to 18 healthy controls for age and sex. Motor impairment was assessed using the NIH Stroke Scale (NIHSS), the Fugl-Meyer Scale (FMS), Finger Tapping Score (FTS), Purdue Pegboard and simple reaction times 7 days and 6 months after stroke. At 6 months, a global motor recovery score was computed using the FMS and the FTS to assess motor recovery. Functional MRI scans were obtained using a self-paced finger tapping (FT) task implemented as a block design alternating right FT, left FT and rest. Data were processed using SPM8. In the first level analysis “FT minus fixation” contrasts were computed for the impaired hand. At the second level, multiple regression was used to assess the effect of the motor recovery score on the FT-related motor activity (threshold p<0.05 FWE; extent threshold k=5). Age and FT rate recorded during the experiment were included as covariates in the second level model. Results: As a group, the patients showed good recovery at 6 months. Both patients and controls exhibited a typical pattern of FT task-related activity. Activity in primary motor cortex predicted motor recovery at 6 months, after adjustment for age and FT rate. MNI coordinates = [-34,-14,48] See Figure 1 . Conclusions: Primary motor cortex activity, measured soon after stroke onset, predicts motor recovery assessed at 6 months post-stroke. fMRI measurements made in the early phase of stroke recovery could be useful to derive prognostic biomarkers in both clinical practice and clinical trials investigating novel treatments, such as stem cell administration.

Impaired motor cortex inhibition in patients with amyotrophic lateral sclerosis

Neurology ◽  
1997 ◽  
Vol 49 (5) ◽  
pp. 1292-1298 ◽  
Author(s):  
Ulf Ziemann ◽  
Martin Winter ◽  
Carl D. Reimers ◽  
Karin Reimers ◽  
Frithjof Tergau ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Control Group ◽  
Cortical Silent Period ◽  
Healthy Control ◽  
Als Patients ◽  
Period Duration ◽  
Lateral Sclerosis

We investigated 14 patients with amyotrophic lateral sclerosis (ALS) by paired conditioning-test transcranial magnetic stimulation to test the hypothesis that the motor cortex is hyperexcitable in ALS. Intracortical(corticocortical) inhibition was significantly less in the ALS group than in an age-matched healthy control group (85.3 ± 27.0% versus 45.2± 15.5%, respectively; p < 0.0001). In contrast, intracortical facilitation, motor threshold, and cortical silent period duration in the ALS patients were not different from the control group. We suggest that the selective abnormality of intracortical inhibition is best compatible with an impaired function of inhibitory interneuronal circuits in the motor cortex that in turn renders the corticomotoneuron hyperexcitable.

scholarly journals Clinical and Electrophysiological Hints to TMS in De Novo Patients with Parkinson’s Disease and Progressive Supranuclear Palsy

2020 ◽  
Vol 10 (4) ◽  
pp. 274
Author(s):  
Francesco Fisicaro ◽  
Giuseppe Lanza ◽  
Mariagiovanna Cantone ◽  
Raffaele Ferri ◽  
Giovanni Pennisi ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Progressive Supranuclear Palsy ◽  
De Novo ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Small Sample ◽  
Conduction Time ◽  
Resting Motor Threshold

Background: Transcranial magnetic stimulation (TMS) can non-invasively probe cortical excitability in movement disorders, although clinical significance is still controversial, especially at early stages. We compare single-pulse TMS in two prototypic synucleinopathy and tauopathy—i.e., Parkinson’s disease (PD) and Progressive Supranuclear Palsy (PSP), respectively—to find neurophysiological differences and identify early measures associated with cognitive impairment. Methods: 28 PD and 23 PSP de novo patients were age-matched with 28 healthy controls, all right-handed and drug-free. Amplitude and latency of motor evoked potentials (MEP), central motor conduction time, resting motor threshold (rMT), and cortical silent period (CSP) were recorded through a figure-of-eight coil from the First Dorsal Interosseous muscle (FDI), bilaterally. Results: Mini Mental Examination and Frontal Assessment Battery (FAB) scored worse in PSP; PD had worse FAB than controls. Higher MEP amplitude from right FDI in PD and PSP than controls was found, without difference between them. CSP was bilaterally longer in patients than controls, but similar between patient groups. A positive correlation between FAB and rMT was observed in PSP, bilaterally. Conclusions: Despite the small sample size, PD and PSP might share, at early stage, a similar global electrocortical asset. rMT might detect and possibly predict cognitive deterioration in PSP.

scholarly journals Persistent Motor System Abnormalities in Formerly Concussed Athletes

2011 ◽  
Vol 46 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Louis De Beaumont ◽  
David Mongeon ◽  
Sébastien Tremblay ◽  
Julie Messier ◽  
François Prince ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor System ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Football Players ◽  
System Function ◽  
Motor Execution ◽  
Cortical Silent Period ◽  
Motor Cortex Excitability ◽  
Execution Speed

Context: The known detrimental effects of sport concussions on motor system function include balance problems, slowed motor execution, and abnormal motor cortex excitability. Objective: To assess whether these concussion-related alterations of motor system function are still evident in collegiate football players who sustained concussions but returned to competition more than 9 months before testing. Design: Case-control study. Setting: University laboratory. Patients or Other Participants: A group of 21 active, university-level football players who had experienced concussions was compared with 15 university football players who had not sustained concussions. Intervention(s): A force platform was used to assess center-of-pressure (COP) displacement and COP oscillation regularity (approximate entropy) as measures of postural stability in the upright position. A rapid alternating-movement task was also used to assess motor execution speed. Transcranial magnetic stimulation over the motor cortex was used to measure long-interval intracortical inhibition and the cortical silent period, presumably reflecting γ-aminobutyric acid subtype B receptor-mediated intracortical inhibition. Main Outcome Measure(s): COP displacement and oscillation regularity, motor execution speed, long-interval intracortical inhibition, cortical silent period. Results: Relative to controls, previously concussed athletes showed persistently lower COP oscillation randomness, normal performance on a rapid alternating-movement task, and more M1 intracortical inhibition that was related to the number of previous concussions. Conclusions: Sport concussions were associated with pervasive changes in postural control and more M1 intracortical inhibition, providing neurophysiologic and behavioral evidence of lasting, subclinical changes in motor system integrity in concussed athletes.

Motor-Evoked Potentials of the Abductor Hallucis Muscle and Their Relationship with Foot Arch Functional Anatomy

2017 ◽  
Vol 107 (5) ◽  
pp. 467-470
Author(s):  
Tyrone Mayorga ◽  
Erato Giokas ◽  
Anaida Abagyan ◽  
Dhaval Patel ◽  
Yasmin Sarraf ◽  
...  
Keyword(s):  
Motor Evoked Potential ◽  
Silent Period ◽  
Functional Neuroanatomy ◽  
Motor Threshold ◽  
Abductor Hallucis ◽  
Cortical Silent Period ◽  
Foot Length ◽  
Resting Motor Threshold ◽  
Foot Arch ◽  
Period Duration

Background: The present study aimed to investigate the correlation between abductor hallucis (AH) muscle motor evoked potential (MEP) amplitude and foot arch anatomy. Methods: Twelve healthy individuals underwent foot arch measurement using a digital photographic technique and measurements of cortical excitability using transcranial magnetic stimulation applied on the cortical representation area of the right AH muscle. Truncated foot length and dorsal height were then measured and used to create the arch height index (AHI). Resting motor threshold, MEP amplitude (using a stimulation intensity of 110% resting motor threshold), and cortical silent period duration were also measured. Results: Mean ± SE values were as follows: truncated foot length, 16.72 ± 0.3 cm; dorsal height, 5.62 ± 0.13 cm; AHI, 0.34 ± 0.01; resting motor threshold, 81.6% ± 2.12%; MEP amplitude, 0.71 ± 0.1 mV; and cortical silent period duration, 108.05 ± 0.45 msec. A significant correlation was found between MEP amplitude and AHI (Spearman's rho: P &lt; .01). Conclusions: These results indicate that AH muscle functional neuroanatomy measurements are reliable and might be used by clinicians and therapists to investigate foot arch physiology and monitor the efficacy of treatments and rehabilitative protocols.

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.

scholarly journals Cortical silent period reflects individual differences in action stopping performance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mario Paci ◽  
Giulio Di Cosmo ◽  
Mauro Gianni Perrucci ◽  
Francesca Ferri ◽  
Marcello Costantini
Keyword(s):  
Individual Differences ◽  
Response Inhibition ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Stop Signal ◽  
Stop Signal Task ◽  
Behavioral Differences ◽  
Cortical Silent Period ◽  
Stop Signal Reaction Time

AbstractInhibitory control is the ability to suppress inappropriate movements and unwanted actions, allowing to regulate impulses and responses. This ability can be measured via the Stop Signal Task, which provides a temporal index of response inhibition, namely the stop signal reaction time (SSRT). At the neural level, Transcranial Magnetic Stimulation (TMS) allows to investigate motor inhibition within the primary motor cortex (M1), such as the cortical silent period (CSP) which is an index of GABAB-mediated intracortical inhibition within M1. Although there is strong evidence that intracortical inhibition varies during action stopping, it is still not clear whether differences in the neurophysiological markers of intracortical inhibition contribute to behavioral differences in actual inhibitory capacities. Hence, here we explored the relationship between intracortical inhibition within M1 and behavioral response inhibition. GABABergic-mediated inhibition in M1 was determined by the duration of CSP, while behavioral inhibition was assessed by the SSRT. We found a significant positive correlation between CSP’s duration and SSRT, namely that individuals with greater levels of GABABergic-mediated inhibition seem to perform overall worse in inhibiting behavioral responses. These results support the assumption that individual differences in intracortical inhibition are mirrored by individual differences in action stopping abilities.

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