Effect of Transcranial Magnetic Stimulation on Bimanual Movements

2005 ◽  
Vol 93 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Jen-Tse Chen ◽  
Yung-Yang Lin ◽  
Din-E Shan ◽  
Zin-An Wu ◽  
Mark Hallett ◽  
...  

Transcranial magnetic stimulation (TMS) of the motor cortex can interrupt voluntary contralateral rhythmic limb movements. Using the method of “resetting index” (RI), our study investigated the TMS effect on different types of bimanual movements. Six normal subjects participated. For unimanual movement, each subject tapped either the right or left index finger at a comfortable rate. For bimanual movement, index fingers of both hands tapped in the same (in-phase) direction or in the opposite (antiphase) direction. TMS was applied to each hemisphere separately at various intensities from 0.5 to 1.5 times motor threshold (MT). TMS interruption of rhythm was quantified by RI. For the unimanual movements, TMS disrupted both contralateral and ipsilateral rhythmic hand movements, although the effect was much less in the ipsilateral hand. For the bimanual in-phase task, TMS could simultaneously reset the rhythmic movements of both hands, but the effect on the contralateral hand was less and the effect on the ipsilateral hand was more compared with the unimanual tasks. Similar effects were seen from right and left hemisphere stimulation. TMS had little effect on the bimanual antiphase task. The equal effect of right and left hemisphere stimulation indicates that neither motor cortex is dominant for simple bimanual in-phase movement. The smaller influence of contralateral stimulation and the greater effect of ipsilateral stimulation during bimanual in-phase movement compared with unimanual movement suggest hemispheric coupling. The antiphase movements were resistant to TMS disruption, and this suggests that control of rhythm differs in the 2 tasks. TMS produced a transient asynchrony of movements on the 2 sides, indicating that both motor cortices might be downstream of the clocking command or that the clocking is a consequence of the 2 hemispheres communicating equally with each other.

2020 ◽  
Author(s):  
Isaac N. Gomez ◽  
Kara Ormiston ◽  
Ian Greenhouse

AbstractAction preparation involves widespread modulation of motor system excitability, but the precise mechanisms are unknown. In this study, we investigated whether intracortical inhibition changes in task-irrelevant muscle representations during action preparation. We used transcranial magnetic stimulation (TMS) combined with electromyography in healthy human adults to measure motor evoked potentials (MEPs) and cortical silent periods (CSPs) in task-irrelevant muscles during the preparatory period of simple delayed response tasks. In Experiment 1, participants responded with the left-index finger in one task condition and the right-index finger in another task condition, while MEPs and CSPs were measured from the contralateral non-responding and tonically contracted index finger. During Experiment 2, participants responded with the right pinky finger while MEPs and CSPs were measured from the tonically contracted left-index finger. In both experiments, MEPs and CSPs were compared between the task preparatory period and a resting intertrial baseline. The CSP duration during response preparation decreased from baseline in every case. A laterality difference was also observed in Experiment 1, with a greater CSP reduction during the preparation of left finger responses compared to right finger responses. MEP amplitudes showed no modulation during movement preparation in any of the three response conditions. These findings indicate cortical inhibition associated with task-irrelevant muscles is transiently released during action preparation and implicate a novel mechanism for the controlled and coordinated release of motor cortex inhibition.New & NoteworthyIn this study we observed the first evidence of a release of intracortical inhibition in task-irrelevant muscle representations during response preparation. We applied transcranial magnetic stimulation to elicit cortical silent periods in task-irrelevant muscles during response preparation and observed a consistent decrease in the silent period duration relative to a resting baseline. These findings address the question of whether cortical mechanisms underlie widespread modulation in motor excitability during response preparation.


2004 ◽  
Vol 16 (9) ◽  
pp. 1605-1611 ◽  
Author(s):  
Sara Torriero ◽  
Massimiliano Oliveri ◽  
Giacomo Koch ◽  
Carlo Caltagirone ◽  
Laura Petrosini

Increasing evidence suggests cerebellar involvement in procedural learning. To further analyze its role and to assess whether it has a lateralized influence, in the present study we used a repetitive transcranial magnetic stimulation interference approach in a group of normal subjects performing a serial reaction time task. We studied 36 normal volunteers: 13 subjects underwent repetitive transcranial magnetic stimulation on the left cerebellum and performed the task with the right (6 subjects) or left (7 subjects) hand; 10 subjects underwent repetitive transcranial magnetic stimulation on the right cerebellum and performed the task with the hand ipsilateral (5 subjects) or contralateral (5 subjects) to the stimulation; another 13 subjects served as controls and were not submitted to repetitive transcranial magnetic stimulation; 7 of them performed the task with the right hand and 6 with the left hand. The main results show that interference with the activity of the lateral cerebellum induces a significant decrease of procedural learning: Interference with the right cerebellar hemisphere activity induces a significant decrease in procedural learning regardless of the hand used to perform the serial reaction time task, whereas left cerebellar hemisphere activity seems more linked with procedural learning through the ipsilateral hand. In conclusion, the present study shows for the first time that a transient interference with the functions of the cerebellar cortex results in an impairment of procedural learning in normal subjects and it provides new evidences for interhemispheric differences in the lateral cerebellum.


2009 ◽  
Vol 106 (17) ◽  
pp. 7197-7202 ◽  
Author(s):  
Claudia D. Vargas ◽  
Antoine Aballéa ◽  
Érika C. Rodrigues ◽  
Karen T. Reilly ◽  
Catherine Mercier ◽  
...  

The human primary motor cortex (M1) undergoes considerable reorganization in response to traumatic upper limb amputation. The representations of the preserved arm muscles expand, invading portions of M1 previously dedicated to the hand, suggesting that former hand neurons are reassigned to the control of remaining proximal upper limb muscles. Hand allograft offers a unique opportunity to study the reversibility of such long-term cortical changes. We used transcranial magnetic stimulation in patient LB, who underwent bilateral hand transplantation 3 years after a traumatic amputation, to longitudinally track both the emergence of intrinsic (from the donor) hand muscles in M1 as well as changes in the representation of stump (upper arm and forearm) muscles. The same muscles were also mapped in patient CD, the first bilateral hand allograft recipient. Newly transplanted intrinsic muscles acquired a cortical representation in LB's M1 at 10 months postgraft for the left hand and at 26 months for the right hand. The appearance of a cortical representation of transplanted hand muscles in M1 coincided with the shrinkage of stump muscle representations for the left but not for the right side. In patient CD, transcranial magnetic stimulation performed at 51 months postgraft revealed a complete set of intrinsic hand-muscle representations for the left but not the right hand. Our findings show that newly transplanted muscles can be recognized and integrated into the patient's motor cortex.


1995 ◽  
Vol 73 (6) ◽  
pp. 2608-2611 ◽  
Author(s):  
L. Fadiga ◽  
L. Fogassi ◽  
G. Pavesi ◽  
G. Rizzolatti

1. We stimulated the motor cortex of normal subjects (transcranial magnetic stimulation) while they 1) observed an experimenter grasping 3D-objects, 2) looked at the same 3D-objects, 3) observed an experimenter tracing geometrical figures in the air with his arm, and 4) detected the dimming of a light. Motor evoked potentials (MEPs) were recorded from hand muscles. 2. We found that MEPs significantly increased during the conditions in which subjects observed movements. The MEP pattern reflected the pattern of muscle activity recorded when the subjects executed the observed actions. 3. We conclude that in humans there is a system matching action observation and execution. This system resembles the one recently described in the monkey.


2019 ◽  
Author(s):  
Cécilia Neige ◽  
Dylan Rannaud Monany ◽  
Cathy M. Stinear ◽  
Winston D. Byblow ◽  
Charalambos Papaxanthis ◽  
...  

AbstractMotor imagery (MI) is the mental simulation of an action without any apparent muscular contraction. By means of transcranial magnetic stimulation, few studies revealed a decrease of short-interval intracortical inhibition (SICI) within the primary motor cortex. However, this decrease is ambiguous, as one would expect greater inhibition during MI to prevent overt motor output. The current study investigated the extent of SICI modulation during MI through a methodological and a conceptual reconsideration of i) the importance of parameters to assess SICI (Exp.1) and ii) the inhibitory process within the primary motor cortex as an inherent feature of MI (Exp.2). Participants performed two tasks: 1) rest and 2) imagery of isometric abduction of the right index finger. Using transcranial magnetic stimulation, motor evoked potentials were elicited in the right first dorsal interosseous muscle. An adaptive threshold-hunting paradigm was used, where the stimulus intensity required to maintain a fixed motor evoked potential amplitude was quantified. To test SICI, we conditioned the test stimulus with a conditioning stimulus (CS) of different intensities. Results revealed an Intensity by Task interaction showing that SICI decreased during MI as compared to rest only for the higher CS intensity (Exp.1). At the lowest CS intensities, a Task main effect revealed that SICI increased during MI (Exp.2). SICI modulation during MI depends critically on the CS intensity. By optimising CS intensity, we have shown that SICI circuits may increase during MI, revealing a potential mechanism to prevent the production of a movement while the motor system is activated.HighlightsExcitatory and inhibitory neural processes interact during motor imagery, as the motor regions are activated but no movement is produced.The current study investigated the extent of short interval intracortical inhibition modulation (SICI) during motor imagery.When using optimal settings, SICI increased during motor imagery, likely to prevent the production of an overt movement.


Cephalalgia ◽  
2008 ◽  
Vol 28 (3) ◽  
pp. 203-208 ◽  
Author(s):  
AR Artemenko ◽  
AL Kurenkov ◽  
EG Filatova ◽  
SS Nikitin ◽  
H Kaube ◽  
...  

We studied the excitability of the visual and motor cortex in 36 patients with frequent migraine without aura (30 women, mean age 38.6 ± 10.0 years) before and after treatment with topiramate (100 mg/day) using transcranial magnetic stimulation. Treatment with topiramate resulted in reduction of both headache frequency (12.0 ± 1.3 to 5.8 ± 3.2 migraine days per month; P = 0.004) and cortical excitability: motor cortex thresholds increased on the right side from 43.8 ± 7.5% to 47.7 ± 9.2% ( P = 0.049) and on the left side from 43.4 ± 7.0% to 47.2 ± 9.6% ( P = 0.047), and phosphene thresholds increased from 58.9 ± 11.1% to 71.2 ± 11.2% ( P = 0.0001). Reduction of headache frequency correlated inversely with an increase of visual thresholds and did not correlate with motor thresholds. The effect of topiramate in migraine prevention is complex and can not be explained simply by inhibition of cortical excitability.


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