Comparison of Muscle MEPs From Transcranial Magnetic and Electrical Stimulation and Appearance of Reflexes in Horses
| Autor: | Sanne Lotte Journée, Henricus Louis Journée, Hanneke Irene Berends, Steven Michael Reed, Cornelis Marinus de Bruijn, Cathérine John Ghislaine Delesalle |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
transcranial stimulation
040301 veterinary sciences RETICULOSPINAL NEURONS Stimulation MOTOR-EVOKED-POTENTIALS CORTICOSPINAL TRACT lcsh:RC321-571 0403 veterinary science 03 medical and health sciences 0302 clinical medicine Nuclear magnetic resonance Medicine SENSORY NERVE-CONDUCTION Veterinary Sciences Corneal reflex PERIPHERAL-NERVE lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry horses Original Research startle reflex Tibialis Cranialis motor potentials business.industry neurology General Neuroscience food and beverages 04 agricultural and veterinary sciences Spinal cord VOLUNTARY CONTRACTION BLINK REFLEX BRAIN-STIMULATION medicine.anatomical_structure TMS Brain stimulation Corticospinal tract Reflex Brainstem SPINAL-CORD HUMAN CEREBRAL-CORTEX business TES 030217 neurology & neurosurgery Neuroscience |
| Zdroj: | Frontiers in Neuroscience, Vol 14 (2020) Frontiers in Neuroscience, 14:570372, 1-20. Frontiers Media SA FRONTIERS IN NEUROSCIENCE Frontiers in Neuroscience |
| ISSN: | 1662-4548 1662-453X |
| Popis: | Introduction: Transcranial electrical (TES) and magnetic stimulation (TMS) are both used for assessment of the motor function of the spinal cord in horses. Muscular motor evoked potentials (mMEP) were compared intra-individually for both techniques in five healthy horses. mMEPs were measured twice at increasing stimulation intensity steps over the extensor carpi radialis (ECR), tibialis cranialis (TC), and caninus muscles. Significance was set at p < 0.05. To support the hypothesis that both techniques induce extracranially elicited mMEPs, literature was also reviewed.Results: Both techniques show the presence of late mMEPs below the transcranial threshold appearing as extracranially elicited startle responses. The occurrence of these late mMEPs is especially important for interpretation of TMS tracings when coil misalignment can have an additional influence. Mean transcranial motor latency times (MLT; synaptic delays included) and conduction velocities (CV) of the ECR and TC were significantly different between both techniques: respectively, 4.2 and 5.5 ms (MLT TMS --MLT TES ), and -7.7 and -9.9 m/s (CV TMS -CV TES ). TMS and TES show intensity-dependent latency decreases of, respectively, -2.6 (ECR) and -2.7 ms (TC)/30% magnetic intensity and -2.6 (ECR) and -3.2 (TC) ms/30V. When compared to TMS, TES shows the lowest coefficients of variation and highest reproducibility and accuracy for MLTs. This is ascribed to the fact that TES activates a lower number of cascaded interneurons, allows for multipulse stimulation, has an absence of coil repositioning errors, and has less sensitivity for varying degrees of background muscle tonus. Real axonal conduction times and conduction velocities are most closely approximated by TES.Conclusion: Both intracranial and extracranial mMEPs inevitably carry characteristics of brainstem reflexes. To avoid false interpretations, transcranial mMEPs can be identified by a stepwise latency shortening of 15-20 ms when exceeding the transcranial motor threshold at increasing stimulation intensities. A ring block around the vertex is advised to reduce interference by extracranial mMEPs. mMEPs reflect the functional integrity of the route along the brainstem nuclei, extrapyramidal motor tracts, propriospinal neurons, and motoneurons. The corticospinal tract appears subordinate in horses. TMS and TES are interchangeable for assessing the functional integrity of motor functions of the spinal cord. However, TES reveals significantly shorter MLTs, higher conduction velocities, and better reproducibility. |
| Databáze: | OpenAIRE |
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