Changes of multisegmental responses of the calf muscles during transcranial magnetic stimulation and electrical stimulation of peripheral nerve

2019 ◽  
Vol 12 (2) ◽  
pp. 433-434
Author(s):  
A. Militskova ◽  
G. Yafarova ◽  
T. Baltina ◽  
I. Lavrov
2009 ◽  
Vol 2 (3) ◽  
pp. 168-173 ◽  
Author(s):  
Mark S. Mennemeier ◽  
William J. Triggs ◽  
Kenneth C. Chelette ◽  
A.J. Woods ◽  
Timothy A. Kimbrell ◽  
...  

2021 ◽  
Author(s):  
S.S. Ananiev ◽  
D.A. Pavlov ◽  
R.N. Yakupov ◽  
V.A. Golodnova ◽  
M.V. Balykin

The study was conducted on 22 healthy men aged 18-23 years. The primary motor cortex innervating the lower limb was stimulated with transcranial magnetic stimulation. Using transcutaneous electrical stimulation of the spinal cord, evoked motor responses of the muscles of the lower extremities were initiated when electrodes were applied cutaneous between the spinous processes in the Th11-Th12 projection. Research protocol: Determination of the thresholds of BMO of the muscles of the lower extremities during TESCS; determination of the BMO threshold of the TA muscle in TMS; determination of the thresholds of the BMO of the muscles of the lower extremities during TESCS against the background of 80% and 90% TMS. It was found that magnetic stimulation of the motor cortex of the brain leads to an increase in the excitability of the neural structures of the lumbar thickening of the spinal cord and an improvement in neuromuscular interactions. Key words: transcranial magnetic stimulation, transcutaneous electrical stimulation of the spinal cord, neural networks, excitability, neuromuscular interactions.


2004 ◽  
Vol 100 (3) ◽  
pp. 560-564 ◽  
Author(s):  
Dirk De Ridder ◽  
Gert De Mulder ◽  
Vincent Walsh ◽  
Neil Muggleton ◽  
Stefan Sunaert ◽  
...  

✓ Tinnitus is a distressing symptom that affects up to 15% of the population for whom no satisfactory treatment exists. The authors present a novel surgical approach for the treatment of intractable tinnitus, based on cortical stimulation of the auditory cortex. Tinnitus can be considered an auditory phantom phenomenon similar to deafferentation pain, which is observed in the somatosensory system. Tinnitus is accompanied by a change in the tonotopic map of the auditory cortex. Furthermore, there is a highly positive association between the subjective intensity of the tinnitus and the amount of shift in tinnitus frequency in the auditory cortex, that is, the amount of cortical reorganization. This cortical reorganization can be demonstrated by functional magnetic resonance (fMR) imaging. Transcranial magnetic stimulation (TMS) is a noninvasive method of activating or deactivating focal areas of the human brain. Linked to a navigation system that is guided by fMR images of the auditory system, TMS can suppress areas of cortical plasticity. If it is successful in suppressing a patient's tinnitus, this focal and temporary effect can be perpetualized by implanting a cortical electrode. A neuronavigation-based auditory fMR imaging-guided TMS session was performed in a patient who suffered from tinnitus due to a cochlear nerve lesion. Complete suppression of the tinnitus was obtained. At a later time an extradural electrode was implanted with the guidance of auditory fMR imaging navigation. Postoperatively, the patient's tinnitus disappeared and remains absent 10 months later. Focal extradural electrical stimulation of the primary auditory cortex at the area of cortical plasticity is capable of suppressing contralateral tinnitus completely. Transcranial magnetic stimulation may be an ideal method for noninvasive studies of surgical candidates in whom stimulating electrodes might be implanted for tinnitus suppression.


Author(s):  
James Louis Nuzzo ◽  
David S. Kennedy ◽  
Harrison T. Finn ◽  
Janet Louise Taylor

We examined if transcranial magnetic stimulation (TMS) is a valid tool for assessment of voluntary activation of the knee extensors in healthy individuals. Maximal M-waves (Mmax) of vastus lateralis (VL) were evoked with electrical stimulation of femoral nerve (FNS); Mmax of medial hamstrings (HS) was evoked with electrical stimulation of sciatic nerve branches; motor evoked potentials (MEPs) of VL and HS were evoked with TMS; superimposed twitches (SIT) of knee extensors were evoked with FNS and TMS. In Study 1, TMS intensity (69% output(SD 5)) was optimized for MEP sizes, but guidelines for test validity could not be met. Agonist VL MEPs were too small (51.4% Mmax(SD 11.9); guideline ≥70% Mmax) and antagonist HS MEPs were too big (16.5% Mmax(SD 10.3); guideline <10% Mmax). Consequently, the TMS estimated resting twitch (99.1 N(SD 37.2)) and FNS resting twitch (142.4 N(SD 41.8)) were different. In Study 2, SITs at 90% maximal voluntary contraction (MVC) were similar between TMS (16.1 N(SD 10.3)) and FNS (20.9 N(SD 16.7)), when TMS intensity was optimized for this purpose, suggesting a procedure that combines TMS SITs with FNS resting twitches could be valid. In Study 3, which tested the TMS intensity (56% output(SD 18)) that evoked the largest SIT at 90%MVC, voluntary activation from TMS (87.3%(SD 7.1)) and FNS (84.5%(SD 7.6)) were different. In sum, the contemporary procedure for TMS-based voluntary activation of the knee extensors is invalid. A modified procedure improves validity, but only in individuals who meet rigorous inclusion criteria for SITs and MEPs.


2015 ◽  
Vol 114 (4) ◽  
pp. 2285-2294 ◽  
Author(s):  
Davis A. Forman ◽  
Devin T. G. Philpott ◽  
Duane C. Button ◽  
Kevin E. Power

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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