The nervous system in horses is a complex network responsible for transmitting signals between different parts of the body. It consists of the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which comprises nerves that extend throughout the body. The nervous system regulates various physiological processes, including movement, sensation, and the coordination of bodily functions. It plays a critical role in processing sensory information and initiating appropriate responses. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of the equine nervous system, including its role in behavior, response to stimuli, and neurological disorders.
KIVALO E, TALANTI S.A good deal of hypothetical evidence has been presented for the view that the antidiuretic and oxytocic hormones are not produced in the posterior lobe of the hypophysis. These hormones appear to originate from a neurosecretory process in the neurosecretory nerve cells of the supraoptic and paraventricular nuclei in the hypothalamus and to migrate within the nerve fibers of the supraoptico-hypophysial tract and into the neurohypophysis (Hild, 1951, 1954 a, b and Hild & Zetler, 1951, 1952, 1953 a, b). Here they are stored and if necessary released. Neurosecretory neurons are described in many s...
Cavasin JP, Miller AD, Duhamel GE.An 8-year-old Anglo-European gelding with progressive neurological signs was humanely destroyed and submitted for necropsy examination. The right parietal cortex was disrupted by a well-demarcated, intraparenchymal, 1.5 cm diameter, tan, homogeneous, dense mass. Microscopical examination was consistent with an astrocytoma, which was confirmed on the basis of strong immunohistochemical labelling for glial fibrillary acidic protein. The neoplastic population lacked immunolabelling for oligodendrocyte transcription factor 2. Labelling for ionized calcium binding adaptor molecule 1 highlighted la...
Cavalleri JM, Metzger J, Hellige M, Lampe V, Stuckenschneider K, Tipold A, Beineke A, Becker K, Distl O, Feige K.Cerebellar abiotrophy (CA) is a rare but significant disease in Arabian horses caused by progressive death of the Purkinje cells resulting in cerebellar ataxia characterized by a typical head tremor, jerky head movements and lack of menace response. The specific role of magnetic resonance imaging (MRI) to support clinical diagnosis has been discussed. However, as yet MR imaging has only been described in one equine CA case. The role of MR morphometry in this regard is currently unknown. Due to the hereditary nature of the disease, genetic testing can support the diagnosis of CA. Therefore, the...
Liu SK, Dolensek EP, Adams CR, Tappe JP.Degenerative myelopathy was diagnosed in six Mongolian wild horses. Three of the horses had a history of ataxia dating from birth to 3 months of age. The clinical signs were uncoordinated movement of the hindlimbs and an abnormally wide-based gait and stance. The other 3 horses had mild ataxia. There were no gross lesions in the brain, vertebrae, or spinal cord. Histologic examination revealed degeneration of the neural processes in the ventral and lateral funiculi of all 6 horses. Myelin sheaths were dilated and vacuolated, and there were swollen, fragmented, or lysed axons. Neuronal degenera...
Nappert G, Vrins A, Breton L, Beauregard M.A retrospective study of 19 ataxic horses admitted to the College of Veterinary Medicine of the University of Montreal during the period of January 1985 to December 1988 is presented. There were 11 cases of cervical vertebral malformation, four of equine degenerative myeloencephalopathy, two of equine protozoal myeloencephalitis, one each of vertebral osteomyelitis and intervertebral disc protrusion. The clinical diagnosis of ataxia in horses requires neurological, radiographic, myelographic, and laboratory examinations.
Mayhew IG, deLahunta A, Whitlock RH, Geary JC.Five horses of mixed breeding and 1 zebra with symmetric tetraparesis and ataxia were studied. There were 2 females and 4 males. Signs of illness were first noticed from birth to 12 months of age. Clinical and pathologic studies were performed when the animals were 4 to 24 months old. Two of the horses were related. All of the subjects had diffuse degenerative myeloencephalopathy. The degeneration was most pronounced in thoracic segments of the spinal cord. Ventral and dorsolateral funiculi were most severely affected. Axonal swelling and abnormal neuronal cell bodies were seen in the gray mat...
Graf von Schweinitz D.Infrared thermographic imaging (ITI) is the most sensitive objective imaging currently available for the detection of back disease in horses. It is, however, only a physiological study primarily of vasomotor tone overlying other superficial tissue factors. Interpretation requires extreme care in imaging protocol and in understanding the significance of altered sympathetic nervous tone and the sympathetic distribution. Most discussions on back pain have centered on nociception and inflammatory events. ITI provides information and localization for more significant than diagnosing areas of hot sp...
Ferreira LVO, Kamura BDC, Oliveira JPM, Chimenes ND, Carvalho M, Santos LAD, Dias-Melicio LA, Amorim RL, Amorim RM.Schwann cells (SCs) are essential for the regenerative processes of peripheral nerve injuries. However, their use in cell therapy is limited. In this context, several studies have demonstrated the ability of mesenchymal stem cells (MSCs) to transdifferentiate into Schwann-like cells (SLCs) using chemical protocols or co-culture with SCs. Here, we describe for the first time the in vitro transdifferentiation potential of MSCs derived from equine adipose tissue (AT) and equine bone marrow (BM) into SLCs using a practical method. In this study, the facial nerve of a horse was collected, cut into ...
Lecoq L, Gains M, Blond L, Parent J.Age and rate of acoustic stimulation affect peak latencies in brainstem auditory evoked responses (BAER) in humans. Those effects are unknown in foals. Objective: Our goals were to (1) establish reference values for BAER in foals by using 3 different stimulation protocols, (2) evaluate the effects of age and stimulation frequencies on BAER tracing in foals up to 6 months old, and (3) compare the data with BAER obtained from foals with central nervous system (CNS) disorders. Methods: Thirty-nine neurologically normal foals and 16 foals with neurologic diseases. Methods: Prospective observationa...
Kurz JP, Schoenhals KE, Hullinger GA, Van Wettere AJ.Syringomyelia is a form of myelodysplasia defined by the formation of one or more fluid-filled cavities within the spinal cord that do not communicate with the central canal. The defect may be congenital or acquired. Clinical signs correlate to the segment of spinal cord affected and include pain, paresis, proprioceptive deficits, alterations in sensation, scoliosis, and autonomic dysfunction. This report describes the clinical and pathologic changes in a case of acquired syringomyelia in a 10-year-old American Paint Horse mare. The horse had a six-week history of progressive proprioceptive de...
van der Kolk JH, Wisse H, van Dijk S.A 20-year-old Arab crossbred gelding was examined because it had apparently suffered an overstimulation of the parasympathetic nervous system for three hours. The clinical signs consisted of hypersalivation, profuse sweating, maximal miosis, fasciculation of the muscles and lateral recumbency in combination with continuous convulsions without diarrhoea. The horse's plasma pseudocholinesterase activity was approximately 10 per cent of normal. It responded well to 10 mg atropine and 50 mg diazepam administered intravenously.
Sheldon SA, Aleman M, Costa LRR, Santoyo AC, Howey Q, Madigan JE.Trigeminal-mediated headshaking results from low-threshold firing of the trigeminal nerve resulting in apparent facial pain. Magnesium may have neuroprotective effects on nerve firing that potentially dampen signs of neuropathic pain. This hypothesis has not been investigated in horses with trigeminal-mediated headshaking. Objective: To investigate head-shaking behavior in affected horses after IV magnesium sulfate infusion. Methods: Six geldings with trigeminal-mediated headshaking. Methods: Prospective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextros...
Hooper PT.Severe spongy degeneration of the central nervous system (CNS) was seen in 11 cattle, 19 sheep, 4 pigs and 1 goat, associated with a variety of hepatic diseases, particularly those caused by hepatotoxic pyrrolizidine alkaloids. It was also seen in a milder form in 2 of 8 horses examined, 1 dog of 5 dogs examined, and in 1 rabbit only of a large number of laboratory animals examined. This paper reports results of experiments which confirmed initially that the CNS disease cold be caused by pyrrolizidine alkaloid intoxication. This was done by poisoning lambs with lasiocarpine. As the disease was...
Kim HT, Gim TJ, Lee JH.A 53-year-old man had chronic low back and leg pain for four years without any history of trauma or neurological manifestations. There was a reduction in symptoms after a lumbar epidural block. Two hours later after the procedure, the patient complained of perineal numbness and lower extremity weakness. The neurological evaluation revealed loss of sensation in the saddle area and the posterior aspect of the leg. The deep-tendon reflexes were decreased in the leg. The patient was unable to urinate. The MRI revealed a schwannoma at the S3 level of the sacral spine with cauda equina compression. ...
Bowker RM, Abhold RH, Caron JP, Sonea IM, Vex KB, Kotyk R.Immunocytochemical analysis of equine synovial membranes revealed presence of several neuropeptides, including substance P (SP), neurokinin A, and neuropeptide Y, in nerves of the radiocarpal, middle carpal, and metacarpophalangeal (fetlock) joints. Within the subsynovium, these neuropeptides were located perivascularly, whereas in the fronds, only neuropeptide Y was restricted to the vessels of the synovial membrane. Only SP and neurokinin A were found in the intimal layer. The intimal layer of the metacarpophalangeal joint contained more SP-immunoreactive fibers than were observed in the int...
Gunning P, Smith A, Fox V, Bolt DM, Lowe J, Sinclair C, Witte TH, Weller R.Lameness is the most common presenting complaint in equine practice. Performing diagnostic nerve blocks is an integral part of any lameness work-up, and is therefore an essential skill for equine practitioners. However, the opportunities for veterinary students to practice this skill are limited. The aim of this study was to design and validate an equine nerve block simulator. It was hypothesised that the simulator would improve students' ability and enhance their confidence in performing nerve blocks. A simulator was built using an equine forelimb skeleton and building foam. Wire wool targets...
Lane JG, Mair TS.The clinical records of 100 cases of headshaking in horses were reviewed. Possible causes of the abnormal behaviour were identified in 11 animals; these included ear mite infestation, otitis interna, cranial nerve dysfunction, cervical injury, ocular disease, guttural pouch mycosis, dental periapical osteitis and suspected vasomotor rhinitis. However, in only two of these could it be shown that correction of the abnormality led to elimination of the headshaking. The additional clinical signs exhibited by the other idiopathic cases of headshaking included evidence of nasal irritation, sneezing ...
Jackman BR, Baxter GM, Doran RE, Allen D, Parks AH.The medical records of 57 horses that had palmar digital neurectomy performed between 1984 and 1990 were reviewed. Neurectomies were performed either by transection and electrocoagulation (47 horses) or by the guillotine technique (10 horses). Middle-aged geldings, Quarter Horses, and Thoroughbreds were significantly over-represented when compared with the hospital population. Horses used as hunter/jumpers also appeared to be over-represented. Complications occurred in 17 (34%) of the 50 horses for which follow-up information was obtained. Recurrence of heel pain was the most common complicati...
Acone F, Botti M, Gazza F, Sanna M, Cappai MG, Bo Minelli L.The sensitive and autonomic innervation of the prostate was studied in some mammals (rat, rabbit, horse, donkey and bull) using gold chloride impregnation. In all the species considered the gland was supplied with conspicuous innervation located in the thickness of the capsule and in trabeculae. The autonomic innervation was constituted by ganglion cells of different sizes (small, medium and large), isolated or in groups of large ganglia also, always located along the course of nerve bundles. The sensitive nervous component, placed more frequently in the most superficial layer of the capsule, ...
Ruby RE, Janes JG.The variety of neurologic diseases which affect horses makes pathologic examination of the nervous system a complex and lengthy process. An understanding of the common causes of neurologic disease, antemortem neurolocalization, and supplementation of the necropsy examination with ancillary testing will help to diagnose a large number of causes of neurologic disease. A general understanding of neuropathology and collaborative relationship with your local pathologists will aid in the definitive diagnosis of neurologic diseases.
Ruíz-López P, Morgaz J, Quirós-Carmona S, Navarrete-Calvo R, Domínguez JM, Gómez-Villamandos RJ, Granados MM.Autonomic nervous system (ANS) activity can modify cardiovascular parameters in response to nociceptive stimuli or drugs in anesthetized animals. The aim of this study was to determine if a surgical nociceptive stimulus and morphine, ketamine, and dobutamine administration would modify ANS activity observed as a change in the mean parasympathetic tone activity (PTAm) in anesthetized horses. In 20 anesthetized horses, heart rate (HR), mean arterial pressure (MAP), and PTAm were monitored before and 1, 3, and 5 min after surgical incision, and before and 10 min after the administration of morphi...
Ehrle A, Ressel L, Ricci E, Singer ER.Pain related to the osseous thoracolumbar spine is common in the equine athlete, with minimal information available regarding soft tissue pathology. The aims of this study were to describe the anatomy of the equine SSL and ISL (supraspinous and interspinous ligaments) in detail and to assess the innervation of the ligaments and their myofascial attachments including the thoracolumbar fascia. Ten equine thoracolumbar spines (T15-L1) were dissected to define structure and anatomy of the SSL, ISL and adjacent myofascial attachments. Morphological evaluation included histology, electron microscopy...
Pavone S, Veronesi F, Piergili Fioretti D, Mandara MT.Gastrointestinal motility disorders represent a significant cause of morbidity and mortality in horses. Previously regarded as a non-pathogenic tapeworm, Anoplocephala perfoliata has been recently associated with equine colic. In this study, pathological changes related to A. perfoliata at the ileocecal junction were investigated in 31 slaughtered horses. Our results showed a significant relationship between parasitic burden and grading of histopathological lesions in both the mucosa and submucosa. Moreover, in infested horses, hypertrophy of the circular muscle layer was determined. Finally, ...
Dorman D.The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This cha...
McBride SD, Roberts K, Hemmings AJ, Ninomiya S, Parker MO.Stress and genotype elicit changes in impulse control in a range of species that are attributable to adaptations in both the central and peripheral nervous system. We examined aspects of this mechanism in the horse by assessing the effect of a dopamine receptor genotype (DRD4) and central dopaminergic tone (measured via spontaneous blink rate [SBR] and behavioral initiation rate [BIR]), on measures of impulsivity, compulsivity (3-choice serial reaction time task) and sympathetic/ parasympathetic system balance (heart rate variability [HRV]). Genotype did not have a significant effect on any of...
Ibrahim M.Rhinoestrus species larvae are considered obligatory parasites of the nasal cavities of equine. This type of myiasis is characterised by sneezing, coughing, olfactory nerve damage and encephalomyelitis. Also, it has a zoonotic importance as the larvae might cause ophthalmomyiasis and conjunctivitis in human. While few studies describing R. purpureus adult fly antennal sensillae are available, the R. usbekistanicus antennal sensillae have never been described. Also, scanty data are available on the adult flies of Rhinoestrus species morphology. For this reason, the current study aimed at identi...
Finno CJ, Valberg SJ, Shivers J, D'Almeida E, Armién AG.Equine degenerative myeloencephalopathy (EDM) is characterized by a symmetric general proprioceptive ataxia in young horses, and is likely underdiagnosed for 2 reasons: first, clinical signs overlap those of cervical vertebral compressive myelopathy; second, histologic lesions--including axonal spheroids in specific tracts of the somatosensory and motor systems--may be subtle. The purpose of this study was (1) to utilize immunohistochemical (IHC) markers to trace axons in the spinocuneocerebellar, dorsal column-medial lemniscal, and dorsospinocerebellar tracts in healthy horses and (2) to dete...
Lemos KR, Marques LC, Deaquino LP, Alessi AC, Machado RZ.An histochemical and immunohistochemical study was carried out to evaluate the mechanisms of immune response of horses experimentally infected by Trypanosoma evansi. For this purpose the HE histochemical stain and the avidin biotin peroxidase method were used. To determine the presence and immunoreactivity of immune cells we used anti-major histocompatibility complex II antibodies. Cellular infiltration phenotype was characterized with the aid of anti-CD3 antibody for T lymphocytes and by anti-BLA 36 antibodies for B lymphocytes. Macrophages were marked with an antibody against myeloid/histyoc...
Shchurova EN, Khudiaev AT.Temperature sense and pain appreciation has been studied in the dermatomes of cauda equine roots in patients with lumbar intervertebral disc hernia before treatment, in the immediate and long-term periods of observation after disc hernia elimination. Temperature sense and pain appreciation has been determined to be disordered not only in the dermatome of compressed root, but in the dermatomes located proximally and distally as well. The manifestation of negative changes was observed to a greater extent during temperature sense examination. After disc hernia elimination the recovery of temperat...
Walker AM, Sellon DC, Cornelisse CJ, Hines MT, Ragle CA, Cohen N, Schott HC.A retrospective study of the medical records of 33 horses was performed to determine the clinical and diagnostic abnormalities associated with temporohyoid osteoarthropathy. Data collected from medical records included signalment, presenting complaints, history, physical examination findings, laboratory data, results of diagnostic imaging studies, and treatments. Follow-up information was obtained from a review of case records; by telephone conversation with the owner, veterinarian, or trainer; or by both methods. Of 33 horses with temporohyoid osteoarthropathy, 29 presented with facial nerve ...
Arboviruses include mosquitoborne and tickborne agents that persist in nature in complex cycles involving birds or mammals, including humans. Arboviral infection can cause fever, headache, meningitis, encephalitis, and sometimes death. During 1996-1997, health departments in 19 states reported to CDC 286 confirmed or probable cases (eight fatal) of arboviral encephalitis in humans (132 cases in 1996 and 154 provisionally in 1997). Surveillance programs in 18 states detected enzootic arboviral activity in mosquito or sentinel or wild bird populations, and cases of arboviral disease were recogni...
