Monitoring spinal cord motor and somatosensory evoked potentials in anesthetized primates

Ghaly, Ramsis F.; Stone, James L.; Lee, J.J.; Ham, Jong Hyun; Levy, Walter J.

doi:10.1080/01616412.1999.11740944

Cited by 9 publications

(2 citation statements)

References 32 publications

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“…1994). In primates, a N 2 O‐methohexital anaesthesia had little effect on the transmission of motor and sensory potentials (Ghaly et al . 1999), but isofluorane had a depressive action on spinal motor potentials (Baker et al .…”

Section: Discussionmentioning

confidence: 99%

Effect of transcranial magnetic stimulation on single‐unit activity in the cat primary visual cortex

Moliadze

Zhao

Eysel

et al. 2003

The Journal of Physiology

217

161

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Journal of Physiologytimed combinations of TMS and visual stimuli to analyse the interaction between TMS and sensory evoked activity at the cortical level. METHODS General proceduresUnder deep anaesthesia induced by a combination of ketamine (20 mg kg _1 I.M., Ketanest, Parke-Davies, Germany) and xylazine (2 mg kg _1 I.M., Rompun, Bayer, Germany), cats (n = 7) were fixed into position using standard stereotaxic methods. All incisions and pressure points were also locally anaesthetised by xylocaine (2 %, Astra Chemicals, Germany). Craniotomies provided access to area 17 of the right hemisphere for single-unit recording, and to area 18 of the left hemisphere for epidural EEG recording, via a 0.5 mm silver ball electrode. Relaxation to enable artificial ventilation of the lungs was achieved with alcuronium chloride (0.15 mg kg _1 h _1 , Alloferin 10, Hoffmann-La Roche, Germany) in 1 % glucose-Ringer solution, infused via the femoral artery. Continuous anaesthesia during recording sessions was achieved by artificial respiration with N 2 O-O 2 (70 %-30 %) and halothane (0.6-2.5 % Fluothane, ICI-Pharma, Germany). Halothane was increased to 2.0 % or more during any potentially painful procedure like handling the contact lenses or performing a new electrode penetration through the dura mater. During the recording sessions the level of anaesthesia was lowered to 0.6-1.0 % halothane to reduce intoxication of the liver during the long-lasting experiments (4-5 days). Blood pressure, heart rate and the EEG were monitored continuously, and the level of anaesthesia was increased (halothane 1.0-2.0 %) when increases in blood pressure or heart rate, or a loss of EEG delta waves signalled distress of the animal. To our knowledge, these procedures are sufficient to prevent the experimental animal from suffering pain.

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Section: Discussionmentioning

confidence: 99%

Effect of transcranial magnetic stimulation on single‐unit activity in the cat primary visual cortex

Moliadze

Zhao

Eysel

et al. 2003

The Journal of Physiology

217

161

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“…A third explanation could be the influence of the strength of stimulation. Previous studies in cats and primates have demonstrated that the MMEP evoked by nearthreshold stimulation of the motor cortex consists of a series of waves generated in the motor cortex and conducted along the corticospinal tract (Haghighi et al 1995;Hiraizumi et al 1996;Ghaly et al 1999). However, Konrad and Tacker (1990) found that suprathreshold stimulation of the motor cortex in cats produced large MMEPs which travelled in the ventral funiculus and, therefore, were probably associated with extrapyramidal tracts, such as the reticulospinal and vestibulospinal tracts.…”

Section: Discussionmentioning

confidence: 99%

Transcranial magnetic stimulation: normal values of magnetic motor evoked potentials in 84 normal horses and influence of height, weight, age and sex

Nollet

Deprez

Ham

et al. 2004

Equine Veterinary Journal

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Reasons for performing study: Cervical spinal corddysfunction is a common problem in equine medicine and the currently available tests give no objective information about the functionality of the nervous tracts. Therefore, transcranial magnetic stimulation (TMS) was performed in 84 healthy horses of different height in order to have an objective measure for the integrity of the descending motor tracts in normal horses. Objectives: To obtain reference values for onset latency and peak-to-peak amplitude of magnetic motor evoked potentials (MMEPs) and to evaluate the possible effect of height, age and gender on the neurophysiological measures. Methods: All horses were sedated and stimulated transcranially by using a magnetic coil placed on the forehead. The stimulator triggered the sweep of an electromyogram machine that recorded MMEPs bilaterally from needle electrodes in the extensor carpi radialis and cranial tibial muscles. In that way, it was possible to measure latency between stimulus and onset of response. Results: A significant difference was found between recordings made in the fore-and hindlimbs; MMEPs recorded in the front legs had a shorter onset latency and higher peak-topeak amplitude. Mean ± s.d. normal values for onset latency of 19.32 ± 2.50 and 30.54 ± 5.28 msecs and peak-to-peak amplitude values of 9.54 ± 3.73 and 6.62 ± 3.62 mV were obtained for extensor carpi radialis and cranial tibial muscles, respectively. The left-to-right difference in onset latency and peak-to-peak amplitude was not significant. In the same horse, differences up to 0.82 and 1.53 msecs for the extensor carpi radialis and cranial tibial muscles, respectively, lie within the 95% confidence limit and are considered normal. In contrast to onset latency, peak-topeak amplitude showed a very large intra-and interindividual variability, even in the same muscle. To reduce the variability and predict normal values of new individual cases, influence of height, weight, age and sex on the MMEPs were determined. No significant effects of sex were observed on onset latency and peak-to-peak amplitude. The age of the horse had only a small but significant effect on peak-to-peak amplitude, with larger responses in older horses. Height at the withers and weight of the horse, parameters that strongly correlate with the size of the horse, had an important significant influence on onset latency but not on peak-to-peak amplitude. The age of the horse and height at the withers were used to predict peak-to-peak amplitude and onset latency, respectively, in normal horses. Conclusions and potential relevance: TMS is an excellentaddition to the few tools we have for noninvasive imaging of the equine nervous system. Magnetically evoked potentials are highly reproducible and recent advances suggest that the applications of TMS in horses will continue to grow rapidly.

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Somatosensory- and Motor-Evoked Potentials in Surgery of Eloquent Cortex Under General Anesthesia: Advantages and Limitations

Selner

Stone

2016

Functional Mapping of the Cerebral Cortex

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Monitoring spinal cord motor and somatosensory evoked potentials in anesthetized primates

Cited by 9 publications

References 32 publications

Effect of transcranial magnetic stimulation on single‐unit activity in the cat primary visual cortex

Effect of transcranial magnetic stimulation on single‐unit activity in the cat primary visual cortex

Transcranial magnetic stimulation: normal values of magnetic motor evoked potentials in 84 normal horses and influence of height, weight, age and sex

Somatosensory- and Motor-Evoked Potentials in Surgery of Eloquent Cortex Under General Anesthesia: Advantages and Limitations

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