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Nociceptive trigeminal reflexes in non-sedated horses
K O Veres-Nyéki1, M Leandri, C Spadavecchia
1Department of Clinical Veterinary Medicine, Anaesthesiology Division, Vetsuisse-Faculty, University of Berne, Länggassstrasse, Berne CH-3012, Switzerland. kata.veres@vetsuisse.unibe.ch
Veterinary Journal (London, England : 1997)
|June 14, 2011
Summary
Researchers explored nociceptive trigeminal reflexes in horses using electrical nerve stimulation. This study establishes a baseline for diagnosing trigeminal system dysfunction in equine patients.
Area of Science:
- Veterinary Neurology
- Electrophysiology
- Equine Physiology
Background:
- Electrically induced reflexes aid in understanding human trigeminal system physiology and pathophysiology.
- Assessing trigemino-cervical (TCR) and blink reflexes (BR) offers potential diagnostic value in horses.
Purpose of the Study:
- To evoke nociceptive trigeminal reflexes in non-sedated horses.
- To characterize the electrophysiological properties of these reflexes.
- To establish a reference for assessing equine trigeminal system dysfunction.
Main Methods:
- Transcutaneous electrical stimulation of the infraorbital (ION) and supraorbital nerves (SON) in 10 adult Warmblood horses.
- Gradual current increase to determine TCR threshold and evaluate stimulus-response curves.
- Simultaneous assessment of BR and recording of surface electromyographic (EMG) responses from orbicularis oculi, splenius, and cleidomastoideus muscles.
Main Results:
- Noxious electrical stimulation of ION or SON elicited reflex EMG responses with consistent features.
- Increasing stimulus intensity resulted in greater reflex amplitude and shorter latency.
- Enhanced behavioral reactions correlated with stimulus intensity, confirming the nociceptive nature of TCR.
Conclusions:
- Electrophysiological characterization of nociceptive trigeminal reflexes in horses is feasible.
- These findings provide a normative dataset for evaluating trigeminal nerve function and dysfunction in horses.
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