scholarly journals Transcranial electrical stimulation motor-evoked potentials in a spinal cord ischaemia rabbit model

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Yucheng Lu ◽  
Baotao Lv ◽  
Qimin Song

Abstract Background Spinal cord ischaemia animal models were established by selective ligation of the lumbar artery in a craniocaudal direction between the renal artery and the aortic bifurcation. Transcranial electrical stimulation motor-evoked potentials were measured to enable their use in future studies on spinal cord ischaemia protection. Methods Thirty-three New Zealand rabbits were randomly divided into 6 groups. Transcranial electrical stimulation motor-evoked potentials were recorded before vascular ligation, 30 min after vascular ligation, and 2 days after vascular ligation. Motor functions were assessed after surgery and 2 days after vascular ligation. The specimens were taken 2 days after ligation for histopathologic observation. Results With increased numbers of ligations, a transient extension of the latency became clear, but there were no significant differences in the statistical analysis. Analysis of variance after ligation at the same time in each group and t tests before and after ligation (P > 0.05) were not significant. One or 2 ligations did not cause spinal cord ischaemic damage. There were no significant differences before and after ligation for the amplitude (P > 0.05). With increased numbers of ligations, the amplitude before and after ligation was gradually reduced in the 3–5 ligation groups (P < 0.05). Conclusions Ligation of segmental spinal cord vessels on 1 or 2 levels did not cause ischaemic damage. Spinal cord ischaemia was observed after 3, 4, or 5 ligations. The amplitude was more sensitive to spinal cord ischaemia than latency. Spinal cord function can be predicted by early changes in the amplitude.

2004 ◽  
Vol 100 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Katsushige Watanabe ◽  
Takashi Watanabe ◽  
Akio Takahashi ◽  
Nobuhito Saito ◽  
Masafumi Hirato ◽  
...  

✓ The feasibility of high-frequency transcranial electrical stimulation (TES) through screw electrodes placed in the skull was investigated for use in intraoperative monitoring of the motor pathways in patients who are in a state of general anesthesia during cerebral and spinal operations. Motor evoked potentials (MEPs) were elicited by TES with a train of five square-wave pulses (duration 400 µsec, intensity ≤ 200 mA, frequency 500 Hz) delivered through metal screw electrodes placed in the outer table of the skull over the primary motor cortex in 42 patients. Myogenic MEPs to anodal stimulation were recorded from the abductor pollicis brevis (APB) and tibialis anterior (TA) muscles. The mean threshold stimulation intensity was 48 ± 17 mA for the APB muscles, and 112 ± 35 mA for the TA muscles. The electrodes were firmly fixed at the site and were not dislodged by surgical manipulation throughout the operation. No adverse reactions attributable to the TES were observed. Passing current through the screw electrodes stimulates the motor cortex more effectively than conventional methods of TES. The method is safe and inexpensive, and it is convenient for intraoperative monitoring of motor pathways.


2013 ◽  
Vol 110 (6) ◽  
pp. 1311-1322 ◽  
Author(s):  
Parag Gad ◽  
Igor Lavrov ◽  
Prithvi Shah ◽  
Hui Zhong ◽  
Roland R. Roy ◽  
...  

The rat spinal cord isolated from supraspinal control via a complete low- to midthoracic spinal cord transection produces locomotor-like patterns in the hindlimbs when facilitated pharmacologically and/or by epidural electrical stimulation. To evaluate the role of epidural electrical stimulation in enabling motor control (eEmc) for locomotion and posture, we recorded potentials evoked by epidural spinal cord stimulation in selected hindlimb muscles during stepping and standing in adult spinal rats. We hypothesized that the temporal details of the phase-dependent modulation of these evoked potentials in selected hindlimb muscles while performing a motor task in the unanesthetized state would be predictive of the potential of the spinal circuitries to generate stepping. To test this hypothesis, we characterized soleus and tibialis anterior (TA) muscle responses as middle response (MR; 4–6 ms) or late responses (LRs; >7 ms) during stepping with eEmc. We then compared these responses to the stepping parameters with and without a serotoninergic agonist (quipazine) or a glycinergic blocker (strychnine). Quipazine inhibited the MRs induced by eEmc during nonweight-bearing standing but facilitated locomotion and increased the amplitude and number of LRs induced by eEmc during stepping. Strychnine facilitated stepping and reorganized the LRs pattern in the soleus. The LRs in the TA remained relatively stable at varying loads and speeds during locomotion, whereas the LRs in the soleus were strongly modulated by both of these variables. These data suggest that LRs facilitated electrically and/or pharmacologically are not time-locked to the stimulation pulse but are highly correlated to the stepping patterns of spinal rats.


Author(s):  
Vedran Deletis ◽  
Francesco Sala ◽  
Sedat Ulkatan

Transcranial electrical stimulation is a well-recognized method for corticospinal tract (CT) activation. This article explains the use of TES during surgery and highlights the physiology of the motor-evoked potentials (MEPs). It describes the techniques and methods for brain stimulation and recording of responses. There are two factors that determine the depth of the current penetrating the brain, they are: choice of electrode montage for stimulation over the scalp and the intensity of stimulation. D-wave collision technique is a newly developed technique that allows mapping intraoperatively and finding the anatomical position of the CT within the surgically exposed spinal cord. Different mechanisms may be involved in the pathophysiology of postoperative paresis in brain and spinal cord surgeries so that different MEP monitoring criteria can be used to avoid irreversible damage and accurately predict the prognosis.


2020 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Stephanie L. Schwartz ◽  
Emily B. Kale ◽  
Dennis Madden ◽  
Aatif M. Husain

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