Suppression of Corticospinal Excitability During Negative Motor Imagery

2003 ◽  
Vol 90 (4) ◽  
pp. 2303-2309 ◽  
Author(s):  
Young H. Sohn ◽  
Nguyet Dang ◽  
Mark Hallett
Keyword(s):  
Motor Imagery ◽  
Motor Evoked Potentials ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Intracortical Facilitation ◽  
Abductor Pollicis Brevis ◽  
Paired Pulse ◽  
Left Hand ◽  
Resting Motor Threshold ◽  
Conditioning Stimuli

To investigate the effect of negative motor imagery on corticospinal excitability, we performed transcranial magnetic stimulation (TMS) studies in seven healthy subjects during imagination of suppressing movements. Subjects were asked to imagine suppression of TMS-induced twitching movement of their nondominant left hands by attempting to increase the amount of relaxation after receiving an auditory NoGo cue (negative motor imagery), but to imagine squeezing hands after a Go cue (positive motor imagery). Single- and paired-pulse TMS were triggered at 2 s after Go or NoGo cues. Motor-evoked potentials (MEPs) were recorded in the first dorsal interosseus (FDI), abductor pollicis brevis (APB), and abductor digiti minimi (ADM) muscles of the left hand. Paired-pulse TMS with subthreshold conditioning stimuli at interstimulus intervals of 2 (short intracortical inhibition) and 15 ms (intracortical facilitation) and that with suprathreshold conditioning stimuli at interstimulus interval of 80 ms (long intracortical inhibition) were performed in both negative motor imagery and control conditions. Compared with the control state (no imagination), MEP amplitudes of FDI (but not APB and ADM) were significantly suppressed in negative motor imagery, but those from all three muscles were unchanged during positive motor imagery. F-wave responses (amplitudes and persistence) were unchanged during both negative and positive motor imagery. During negative motor imagery, resting motor threshold was significantly increased, but short and long intracortical inhibition and intracortical facilitation were unchanged. The present results demonstrate that excitatory corticospinal drive is suppressed during imagination of suppressing movements.

Abstract TMP43: Differential Cortical Effect Modulated by Anodal, Cathodal and Bihemispheric Transcranial Direct Current Stimulation (tDCS) in Patients With Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Pratik Y Chhatbar ◽  
William DeVries ◽  
Emily Grattan ◽  
Steven A Kautz ◽  
Wuwei Feng
Keyword(s):  
Ischemic Stroke ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Intracortical Inhibition ◽  
Motor Threshold ◽  
Stroke Patients ◽  
Intracortical Facilitation ◽  
Abductor Pollicis Brevis ◽  
Resting Motor Threshold

Introduction: The differential brain modulatory effects across hemispheres from different montages in stroke patients is not well established. We aimed to investigate the cortical excitability on lesional and contra-lesional hemisphere modulated by anodal, cathodal and bihemispheric montage at 4 mA tDCS strengths. Hypothesis: Bihemispheric tDCS montage induces more cortical excitability on the lesional hemisphere. Methods: Eighteen aging stroke patients with unilateral ischemic stroke of 6 or more months and inducible motor evoked potentials (MEP) underwent 3 sessions of 30 minutes 4 mA tDCS combined with occupational therapy. Each session was at least 2 days apart and consisted of one of the 3 different montages: anodal (Anode: lesional C3/C4, Cathode: non-lesional FP1/FP2), cathodal (Anode: lesional FP1/FP2, Cathode: non-lesional C3/C4), or bihemispheric (Anode: lesional C3/C4, Cathode: non-lesional C3/C4). We collected MEP size, short intracortical inhibition (SICI, 3 ms) and intracortical facilitation (ICF, 15 ms) on bilateral abductor pollicis brevis (APB) muscles using single or paired pulse TMS at 5 timepoints (baseline and four post-tDCS 12 minutes apart sessions). Results: All 18 subjects had comparable resting motor threshold (rMT) across 3 montages (see A). Bihemispheric tDCS montage offered significantly larger peak-to-peak MEP responses on the lesioned cortex (ANOVA, F=8.97, P<0.01) but not on the non-lesioned cortex (ANOVA, F=0.86, P=0.42). These differences were apparent in single pulse, SICI and ICF (see B). Conclusion: Our findings support that bihemispheric montage is better suited in post-stroke motor recovery tDCS applications.

Effect of Volitional Inhibition on Cortical Inhibitory Mechanisms

2002 ◽  
Vol 88 (1) ◽  
pp. 333-338 ◽  
Author(s):  
Young H. Sohn ◽  
Katy Wiltz ◽  
Mark Hallett
Keyword(s):  
Index Finger ◽  
Motor Evoked Potentials ◽  
Intracortical Inhibition ◽  
Paired Pulse ◽  
Extensor Indicis Proprius ◽  
Inhibitory Mechanisms ◽  
Abductor Digiti Minimi ◽  
And Control ◽  
Conditioning Stimuli ◽  
Reaction Task

To investigate the effect of volitional inhibition on cortical inhibitory mechanisms, we performed transcranial magnetic stimulation (TMS) studies with a Go/NoGo reaction task in seven healthy subjects. Subjects were asked to extend their right index finger only after Go, but to remain relaxed after NoGo. Single- and paired-pulse TMS were triggered at the average reaction time for the Go response in each subject after Go or NoGo cues. Motor evoked potentials were recorded in the extensor indicis proprius (EIP) and abductor digiti minimi (ADM) muscles of right hand. Paired-pulse TMS with subthreshold conditioning stimuli at interstimulus intervals (ISIs) of 2 ms [short intracortical inhibition (SICI)] and 15 ms [intracortical facilitation (ICF)] and that with suprathreshold conditioning stimuli at ISI of 80 ms [long intracortical inhibition (LICI)] were performed in both Go/NoGo and control conditions. Inhibition of SICI was enhanced in both EIP and ADM after NoGo and was reduced only in EIP after Go. Inhibition of LICI was reduced in both muscles during both conditions, while ICF was not altered. The present results demonstrate that volitional inhibition enhances SICI but reduces LICI nonselectively. These results suggest that these two inhibitory mechanisms act differently during execution and suppression of voluntary movements.

scholarly journals Cortical disinhibition in Parkinson’s disease

Brain ◽  
2020 ◽  
Vol 143 (11) ◽  
pp. 3408-3421 ◽  
Author(s):  
Claudia Ammann ◽  
Michele Dileone ◽  
Cristina Pagge ◽  
Valentina Catanzaro ◽  
David Mata-Marín ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Magnetic Stimulation ◽  
Short Interval ◽  
Intracortical Inhibition ◽  
Motor Threshold ◽  
Intracortical Facilitation ◽  
Low Intensity ◽  
Resting Motor Threshold ◽  
Conditioning Stimuli

Abstract In Parkinson’s disease, striatal dopamine depletion produces profound alterations in the neural activity of the cortico-basal ganglia motor loop, leading to dysfunctional motor output and parkinsonism. A key regulator of motor output is the balance between excitation and inhibition in the primary motor cortex, which can be assessed in humans with transcranial magnetic stimulation techniques. Despite decades of research, the functional state of cortical inhibition in Parkinson’s disease remains uncertain. Towards resolving this issue, we applied paired-pulse transcranial magnetic stimulation protocols in 166 patients with Parkinson’s disease (57 levodopa-naïve, 50 non-dyskinetic, 59 dyskinetic) and 40 healthy controls (age-matched with the levodopa-naïve group). All patients were studied OFF medication. All analyses were performed with fully automatic procedures to avoid confirmation bias, and we systematically considered and excluded several potential confounding factors such as age, gender, resting motor threshold, EMG background activity and amplitude of the motor evoked potential elicited by the single-pulse test stimuli. Our results show that short-interval intracortical inhibition is decreased in Parkinson’s disease compared to controls. This reduction of intracortical inhibition was obtained with relatively low-intensity conditioning stimuli (80% of the resting motor threshold) and was not associated with any significant increase in short-interval intracortical facilitation or intracortical facilitation with the same low-intensity conditioning stimuli, supporting the involvement of cortical inhibitory circuits. Short-interval intracortical inhibition was similarly reduced in levodopa-naïve, non-dyskinetic and dyskinetic patients. Importantly, intracortical inhibition was reduced compared to control subjects also on the less affected side (n = 145), even in de novo drug-naïve patients in whom the less affected side was minimally symptomatic (lateralized Unified Parkinson’s Disease Rating Scale part III = 0 or 1, n = 23). These results suggest that cortical disinhibition is a very early, possibly prodromal feature of Parkinson’s disease.

scholarly journals Preconditioning Stimulus Intensity Alters Paired-Pulse TMS Evoked Potentials

2021 ◽  
Vol 11 (3) ◽  
pp. 326 ◽  
Author(s):  
Vishal Rawji ◽  
Isabella Kaczmarczyk ◽  
Lorenzo Rocchi ◽  
Po-Yu Fong ◽  
John C. Rothwell ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Stimulus Intensity ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Significant Negative Correlation ◽  
Intracortical Inhibition ◽  
Cortical Function ◽  
Paired Pulse ◽  
Resting Motor Threshold ◽  
Statistical Trends

Motor cortex (M1) paired-pulse TMS (ppTMS) probes excitatory and inhibitory intracortical dynamics by measurement of motor-evoked potentials (MEPs). However, MEPs reflect cortical and spinal excitabilities and therefore cannot isolate cortical function. Concurrent TMS-EEG has the ability to measure cortical function, while limiting peripheral confounds; TMS stimulates M1, whilst EEG acts as the readout: the TMS-evoked potential (TEP). Whilst varying preconditioning stimulus intensity influences intracortical inhibition measured by MEPs, the effects on TEPs is undefined. TMS was delivered to the left M1 using single-pulse and three, ppTMS paradigms, each using a different preconditioning stimulus: 70%, 80% or 90% of resting motor threshold. Corticospinal inhibition was present in all three ppTMS conditions. ppTMS TEP peaks were reduced predominantly under the ppTMS 70 protocol but less so for ppTMS 80 and not at all for ppTMS 90. There was a significant negative correlation between MEPs and N45 TEP peak for ppTMS 70 reaching statistical trends for ppTMS 80 and 90. Whilst ppTMS MEPs show inhibition across a range of preconditioning stimulus intensities, ppTMS TEPs do not. TEPs after M1 ppTMS vary as a function of preconditioning stimulus intensity: smaller preconditioning stimulus intensities result in better discriminability between conditioned and unconditioned TEPs. We recommend that preconditioning stimulus intensity should be minimized when using ppTMS to probe intracortical inhibition.

Changes in interhemispheric inhibition from active to resting primary motor cortex during a fine-motor manipulation task

2012 ◽  
Vol 107 (11) ◽  
pp. 3086-3094 ◽  
Author(s):  
Takuya Morishita ◽  
Kazumasa Uehara ◽  
Kozo Funase
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Conditioning Stimulus ◽  
Fine Motor ◽  
Interhemispheric Inhibition ◽  
Left Hand ◽  
Resting Motor Threshold ◽  
Inhibitory Circuit ◽  
Task Conditions

The effect of performance of a sensorimotor task on the interhemispheric inhibition (IHI) induced from the active primary motor cortex (M1) to the resting M1 was examined in 10 right-handed subjects. Transcranial magnetic stimulation (TMS) was performed to produce motor evoked potentials (MEP) in the resting right (Rt)-first dorsal interosseous (FDI). For the paired-TMS paradigm, a conditioning stimulus (CS) was delivered to the Rt-M1, and its intensity was adjusted from 0.6 to 1.4 times the resting motor threshold of the MEP in the left (Lt)-FDI in 0.2 steps. The test stimulus was delivered to the Lt-M1, and its intensity was adjusted to evoke similar MEP amplitudes in the Rt-FDI among the task conditions. The interstimulus interval was fixed at 10 ms. As a sensorimotor task, a fine-motor manipulation (FM) task (using chopsticks to pick up, transport, and release glass balls) was adopted. In addition, an isometric abduction (IA) task was also performed as a control task. These tasks were carried out with the left hand. The IHI from the active to the resting M1 observed during the FM task was markedly increased compared with that induced during the IA task, and this effect was not dependent on the MEP amplitude evoked in the active Lt-FDI by the CS. The present findings suggest that the increased IHI from the active to the resting M1 observed during the FM task was linked to reductions in the activity of the ipsilateral intracortical inhibitory circuit, as we reported previously.

Event-related desynchronization reflects downregulation of intracortical inhibition in human primary motor cortex

2013 ◽  
Vol 110 (5) ◽  
pp. 1158-1166 ◽  
Author(s):  
Mitsuaki Takemi ◽  
Yoshihisa Masakado ◽  
Meigen Liu ◽  
Junichi Ushiba
Keyword(s):  
Motor Cortex ◽  
Motor Imagery ◽  
Sensorimotor Cortex ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Short Interval ◽  
Hand Movement ◽  
Intracortical Inhibition ◽  
Imagery Task ◽  
Event Related Desynchronization

There is increasing interest in electroencephalogram (EEG)-based brain-computer interface (BCI) as a tool for rehabilitation of upper limb motor functions in hemiplegic stroke patients. This type of BCI often exploits mu and beta oscillations in EEG recorded over the sensorimotor areas, and their event-related desynchronization (ERD) following motor imagery is believed to represent increased sensorimotor cortex excitability. However, it remains unclear whether the sensorimotor cortex excitability is actually correlated with ERD. Thus we assessed the association of ERD with primary motor cortex (M1) excitability during motor imagery of right wrist movement. M1 excitability was tested by motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) with transcranial magnetic stimulation (TMS). Twenty healthy participants were recruited. The participants performed 7 s of rest followed by 5 s of motor imagery and received online visual feedback of the ERD magnitude of the contralateral hand M1 while performing the motor imagery task. TMS was applied to the right hand M1 when ERD exceeded predetermined thresholds during motor imagery. MEP amplitudes, SICI, and ICF were recorded from the agonist muscle of the imagined hand movement. Results showed that the large ERD during wrist motor imagery was associated with significantly increased MEP amplitudes and reduced SICI but no significant changes in ICF. Thus ERD magnitude during wrist motor imagery represents M1 excitability. This study provides electrophysiological evidence that a motor imagery task involving ERD may induce changes in corticospinal excitability similar to changes accompanying actual movements.

scholarly journals The fall and rise of corticomotor excitability with cancellation and reinitiation of prepared action

2014 ◽  
Vol 112 (11) ◽  
pp. 2707-2717 ◽  
Author(s):  
H. J. MacDonald ◽  
J. P. Coxon ◽  
C. M. Stinear ◽  
W. D. Byblow
Keyword(s):  
Motor Behavior ◽  
Motor Evoked Potentials ◽  
Threshold Model ◽  
Intracortical Inhibition ◽  
Initial Increase ◽  
Delayed Response ◽  
Corticomotor Excitability ◽  
Left Hand ◽  
Human Participants ◽  
Response Task

The sudden cancellation of a motor action, known as response inhibition (RI), is fundamental to human motor behavior. The behavioral selectivity of RI can be studied by cueing cancellation of only a subset of a planned response, which markedly delays the remaining executed components. The present study examined neurophysiological mechanisms that may contribute to these delays. In two experiments, human participants received single- and paired-pulse transcranial magnetic stimulation while performing a bimanual anticipatory response task. Participants performed most trials bimanually (Go trials) and were sometimes cued to cancel the response with one hand while responding with the other (Partial trials). Motor evoked potentials were recorded from left first dorsal interosseous (FDI) as a measure of corticomotor excitability (CME) during Go and Partial trials. CME was temporally modulated during Partial trials in a manner that reflected anticipation, suppression, and subsequent initiation of a reprogrammed response. There was an initial increase in CME, followed by suppression 175 ms after the stop signal, even though the left hand was not cued to stop. A second increase in excitability occurred prior to the (delayed) response. We propose an activation threshold model to account for nonselective RI. To investigate the inhibitory component of our model, we investigated short-latency intracortical inhibition (sICI), but results indicated that sICI cannot fully explain the observed temporal modulation of CME. These neurophysiological and behavioural results indicate that the default mode for reactive partial cancellation is suppression of a unitary response, followed by response reinitiation with an inevitable time delay.

scholarly journals Intermittent single-joint fatiguing exercise reduces TMS-EEG measures of cortical inhibition

2019 ◽  
Vol 121 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Lavender A. Otieno ◽  
George M. Opie ◽  
John G. Semmler ◽  
Michael C. Ridding ◽  
Simranjit K. Sidhu
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Global Analysis ◽  
Intracortical Inhibition ◽  
Corticospinal Excitability ◽  
Cortical Inhibition ◽  
Relaxation Period ◽  
Fatiguing Exercise

Fatiguing intermittent single-joint exercise causes an increase in corticospinal excitability and a decrease in intracortical inhibition when measured with peripherally recorded motor evoked potentials (MEPs) after transcranial magnetic stimulation (TMS). Combined TMS and electroencephalography (TMS-EEG) allows for more direct recording of cortical responses through the TMS-evoked potential (TEP). The aim of this study was to investigate the changes in the excitatory and inhibitory components of the TEP during fatiguing single-joint exercise. Twenty-three young (22 ± 2 yr) healthy subjects performed intermittent 30-s maximum voluntary contractions of the right first dorsal interosseous muscle, followed by a 30-s relaxation period repeated for a total of 15 min. Six single-pulse TMSs and one peripheral nerve stimulation (PNS) to evoke maximal M wave (Mmax) were applied during each relaxation period. A total of 90 TMS pulses and 5 PNSs were applied before and after fatiguing exercise to record MEP and TEP. The amplitude of the MEP (normalized to Mmax) increased during fatiguing exercise ( P < 0.001). There were no changes in local and global P30, N45, and P180 of TEPs during the development of intermittent single-joint exercise-induced fatigue. Global analysis, however, revealed a decrease in N100 peak of the TEP during fatiguing exercise compared with before fatiguing exercise ( P = 0.02). The decrease in N100 suggests a fatigue-related decrease in global intracortical GABAB-mediated inhibition. The increase in corticospinal excitability typically observed during single-joint fatiguing exercise may be mediated by a global decrease in intracortical inhibition. NEW & NOTEWORTHY Fatiguing intermittent single-joint exercise causes an increase in corticospinal excitability and a decrease in intracortical inhibition when measured with transcranial magnetic stimulation (TMS)-evoked potentials from the muscle. The present study provides new and direct cortical evidence, using TMS-EEG to demonstrate that during single-joint fatiguing exercise there is a global decrease in intracortical GABAB-mediated inhibition.

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