Magnetic motor evoked potential monitoring in the rat

1999 ◽  
Vol 91 (2) ◽  
pp. 205-210 ◽  
Author(s):  
R. Dean Linden ◽  
Yi-Ping Zhang ◽  
Darlene A. Burke ◽  
Matthew A. Hunt ◽  
John E. Harpring ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Stimulus Intensity ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Onset Latency ◽  
Content Type ◽  
Cord Injury ◽  
Fine Print

Object. The authors conducted a study to provide an objective electrophysiological assessment of descending motor pathways in rats, which may become a means for predicting outcome in spinal cord injury research. Methods. Transcranial magnetic motor evoked potentials (TMMEPs) were recorded under various conditions in awake, nonanesthetized, restrained rats. Normative data were collected to determine the reproducibility of the model and to evaluate the effect of changing the stimulus intensity on the evoked signals. In addition, an experiment was performed to determine if the TMMEPs produced were the result of auditory startle response (ASR) potentials elicited by the sound generated by the movement of the copper coil inside its casing during magnetic stimulation. Transcranial magnetic motor evoked potentials were elicited after magnetic stimulation. At 100% stimulus intensity, the mean forelimb onset latency was 4.2 ± 0.39 msec, and the amplitude was 9.16 ± 3.44 mV. The hindlimb onset latency was 6.5 ± 0.47 msec, and the amplitude was 11.47 ± 5.25 mV. As the stimulus intensity was decreased, the TMMEP onset latency increased and the response amplitude decreased. The ASR potentials were shown to have longer latencies, smaller amplitudes, and were more variable than those of the TMMEPs. Conclusions. These experiments demonstrate that TMMEPs can be recorded in awake, nonanesthetized rats. The evoked signals were easy to elicit and reproduce. This paper introduces noninvasive TMMEPs as a new technique for monitoring the physiological integrity of the rat spinal cord.

Effect of naloxone on posttraumatic ischemia in experimental spinal contusion

1981 ◽  
Vol 55 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Wise Young ◽  
Eugene S. Flamm ◽  
Harry B. Demopoulos ◽  
John J. Tomasula ◽  
Vincent DeCrescito
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Evoked Potentials ◽  
Somatosensory Evoked Potentials ◽  
Sensory Function ◽  
Thoracic Spinal Cord ◽  
Flow Rates ◽  
Content Type ◽  
Cord Injury ◽  
Fine Print

✓ The effect of naloxone on blood flow and somatosensory evoked potentials was studied in cats subjected to 400 gm-cm contusion injuries of the thoracic spinal cord. Eight cats were treated with 10 mg/kg naloxone 45 to 60 minutes after injury, 11 cats were given 10 ml of saline instead of naloxone, and six cats were neither injured nor treated. Hydrogen clearance was used to measure blood flow in the lateral white columns at the contusion site. Naloxone, given intravenously, significantly improved the blood flow rates in the lateral column white matter. At 2 hours after injury, the mean blood flow in the saline-treated cats fell to 50% (p < 0.01) of preinjury flow rates, whereas it increased 6% (p > 0.50) in naloxone-treated cats, and 12% (p > 0.50) in uninjured cats. At the 3rd hour after injury, the respective flows fell 47% (p < 0.01), and 6% (p > 0.50), and increased 15% (p > 0.50) of the preinjury flow rates. The naloxone-treated cats had striking preservation of sensory function and somatosensory evoked potentials at 24 hours after injury. At 24 hours, responses had returned in all the naloxone-treated cats and in only 11% of the saline-treated cats. The probability of this combination of events occurring by chance is 0.0030. The authors conclude that naloxone may be useful for the treatment of spinal cord injury. The mechanism of the effect is unknown.

Motor Evoked Potentials

2016 ◽  
pp. 592-605
Author(s):  
Jeffrey A. Strommen ◽  
Andrea J. Boon
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Standard Of Care ◽  
Transcranial Electrical Stimulation ◽  
Pharmacological Agents ◽  
Physiological Variables ◽  
Stimulation Parameters ◽  
Cord Injury

Motor evoked potentials (MEP) may be used in the diagnosis of central and peripheral neurological disorders and have become the standard of care in many operative procedures as a means to monitor the motor pathways.In the awake patient, transcranial magnetic stimulation (TMS) can be utilized with surface or subcutaneous muscle recordings to identify central conduction abnormalities, as well as assist with prognosis, in conditions such as multiple sclerosis, stroke, spinal cord injury, Parkinson’s disease, hereditary spastic paraplegia, or ALS. In the operating theater, transcranial electrical stimulation with recording from the spinal cord, root, peripheral nerve, or muscle can be used to prevent spinal cord damage, determine continuity of roots or peripheral nerves, and assist with surgical planning. MEP are significantly affected by many physiological variables and pharmacological agents. Various techniques in regards to simulation sites, stimulation parameters, and recording techniques and sites need to be modified to enhance the reproducibility and reliability of these responses.

The effects of methylprednisolone and the ganglioside GM1 on acute spinal cord injury in rats

1994 ◽  
Vol 80 (1) ◽  
pp. 97-111 ◽  
Author(s):  
Shlomo Constantini ◽  
Wise Young
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Body Weight Loss ◽  
Ganglioside Gm1 ◽  
Rat Spinal Cord ◽  
Neuroprotective Effects ◽  
Content Type ◽  
Human Spinal Cord ◽  
Cord Injury ◽  
Fine Print

✓ Recent clinical trials have reported that methylprednisolone sodium succinate (MP) or the monosialic ganglioside GM1 improves neurological recovery in human spinal cord injury. Because GM1 may have additive or synergistic effects when used with MP, the authors compared MP, GM1, and MP+GM1 treatments in a graded rat spinal cord contusion model. Spinal cord injury was caused by dropping a rod weighing 10 gm from a height of 1.25, 2.5, or 5.0 cm onto the rat spinal cord at T-10, which had been exposed via laminectomy. The lesion volumes were quantified from spinal cord Na and K shifts at 24 hours after injury and the results were verified histologically in separate experiments. A single dose of MP (30 mg/kg), given 5 minutes after injury, reduced 24-hour spinal cord lesion volumes by 56% (p = 0.0052), 28% (p = 0.0065), and 13% (p > 0.05) in the three injury-severity groups, respectively, compared to similarly injured control groups treated with vehicle only. Methylprednisolone also prevented injury-induced hyponatremia and increased body weight loss in the spine-injured rats. When used alone, GM1 (10 to 30 mg/kg) had little or no effect on any measured variable compared to vehicle controls; when given concomitantly with MP, GM1 blocked the neuroprotective effects of MP. At a dose of 3 mg/kg, GM1 partially prevented MP-induced reductions in lesion volumes, while 10 to 30 mg/kg of GM1 completely blocked these effects of MP. The effects of MP on injury-induced hyponatremia and body weight loss were also blocked by GM1. Thus, GM1 antagonized both central and peripheral effects of MP in spine-injured rats. Until this interaction is clarified, the authors recommend that MP and GM1 not be used concomitantly to treat acute human spinal cord injury. Because GM1 modulates protein kinase activity, protein kinases inhibit lipocortins, and lipocortins mediate anti-inflammatory effects of glucocorticoids, it is proposed that the neuroprotective effects of MP are partially due to anti-inflammatory effects and that GM1 antagonizes the effects of MP by inhibiting lipocortin. Possible beneficial effects of GM1 reported in central nervous system injury may be related to the effects on neural recovery rather than acute injury processes.

Multi-limb acquisition of motor evoked potentials and its application in spinal cord injury

2010 ◽  
Vol 193 (2) ◽  
pp. 210-216 ◽  
Author(s):  
Shrivats Iyer ◽  
Anil Maybhate ◽  
Alessandro Presacco ◽  
Angelo H. All
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Cord Injury

scholarly journals A novel bone-thinning technique for transcranial stimulation motor-evoked potentials in rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuyo Maeda ◽  
Takashi Otsuka ◽  
Takafumi Mitsuhara ◽  
Takahito Okazaki ◽  
Louis Yuge ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Animal Studies ◽  
Histological Analysis ◽  
Motor Evoked Potentials ◽  
Neurological Dysfunction ◽  
Onset Latency ◽  
Sprague Dawley ◽  
Cord Injury ◽  
A New Technique ◽  
Injury Models

AbstractTranscranial electrical stimulated motor-evoked potentials (tcMEPs) are widely used to evaluate motor function in humans, and even in animal studies, tcMEPs are used to evaluate neurological dysfunction. However, there is a dearth of reports on extended tcMEP recordings in both animal models and humans. Therefore, this study examined a new technique for stably recording tcMEPs over several weeks in six healthy female Sprague–Dawley rats. We thinned the skull bone using the skull base and spinal surgery technique to reduce electrical resistance for electrical stimulation. tcMEPs were recorded on days 1, 7, 14, 21, and 28 after surgery. The onset latency and amplitude of tcMEPs from the hindlimbs were recorded and evaluated, and histological analysis was performed. Stable amplitude and onset latency could be recorded over several weeks, and histological analysis indicated no complications attributable to the procedure. Thus, our novel technique allows for less invasive, safer, easier, and more stable extended tcMEP recordings than previously reported techniques. The presently reported technique may be applied to the study of various nerve injury models in rats: specifically, to evaluate the degree of nerve dysfunction and recovery in spinal cord injury, cerebral infarction, and brain contusion models.

Percutaneous flexible bipolar epidural neuroelectrode for spinal cord stimulation

1984 ◽  
Vol 60 (6) ◽  
pp. 1317-1319 ◽  
Author(s):  
Alfred G. Kaschner ◽  
Wilhelm Sandmann ◽  
Heinz Larkamp
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Epidural Space ◽  
Somatosensory Evoked Potentials ◽  
Spinal Cord Stimulation ◽  
Spinal Cord Ischemia ◽  
Aortic Occlusion ◽  
Content Type ◽  
Fine Print

✓ This article describes a new flexible bipolar neuroelectrode which is inserted percutaneously into the epidural space for segmental spinal cord stimulation. This electrode was used in experiments with dogs and monkeys for recording cortical somatosensory evoked potentials in order to identify intraoperative spinal cord ischemia during periods of aortic occlusion.

Therapeutic trial of hypercarbia and hypocarbia in acute experimental spinal cord injury

1984 ◽  
Vol 61 (5) ◽  
pp. 925-930 ◽  
Author(s):  
Ronald W. J. Ford ◽  
David N. Malm
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Cord Injuries ◽  
Mortality Rates ◽  
Therapeutic Trial ◽  
Tissue Preservation ◽  
Content Type ◽  
Experimental Spinal Cord Injury ◽  
Cord Injury ◽  
Fine Print

✓ Hypocarbia, normocarbia, or hypercarbia was maintained for an 8-hour period beginning 30 minutes after acute threshold spinal cord injuries in cats. No statistically significant differences in neurological recovery or histologically assessed tissue preservation were found among the three groups of animals 6 weeks after injury. No animal recovered the ability to walk. It is concluded that maintenance of hypercarbia or hypocarbia during the early postinjury period is no more therapeutic than maintenance of normocarbia. Mortality rates and tissue preservation data suggest, however, that postinjury hypocarbia may be less damaging than hypercarbia.

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