Neurology in horses encompasses the study of the equine nervous system, including its structure, function, and associated disorders. The equine nervous system is divided into the central nervous system (CNS), consisting of the brain and spinal cord, and the peripheral nervous system (PNS), which includes nerves extending throughout the body. Neurological conditions in horses can manifest as gait abnormalities, behavioral changes, or sensory deficits. Common neurological disorders include equine protozoal myeloencephalitis (EPM), cervical vertebral stenotic myelopathy (CVSM), and equine herpesvirus myeloencephalopathy (EHM). Diagnostic approaches may involve clinical evaluation, imaging techniques, and laboratory tests. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, pathophysiology, diagnosis, and management of neurological disorders in horses.
Marcinkowska M, Bucki A, Panek D, Siwek A, Fajkis N, Bednarski M, Zygmunt M, Godyń J, Del Rio Valdivieso A, Kotańska M, Kołaczkowski M....Serotonin 5-HT receptors, butyrylcholinesterase (BuChE) and oxidative stress are related to the pathophysiology of Alzheimer's disease. Inhibition of BuChE provides symptomatic treatment of the disease and the same effect was demonstrated for 5-HT antagonists in clinical trials. Oxidative stress is regarded as a major and primary factor contributing to the development of Alzheimer's disease; therefore, antioxidant agents may provide a disease-modifying effect. Combining BuChE inhibition, 5-HT antagonism, and antioxidant properties may result in multitarget-directed ligands providing cognitio...
Morales Gómez AM, Zhu S, Palmer S, Olsen E, Ness SL, Divers TJ, Bischoff K, Mohammed HO.Neurofilaments (NFs) are structural proteins of neurons that are released in significant quantities in the cerebrospinal fluid and blood as a result of neuronal degeneration or axonal damage. Therefore, NFs have potential as biomarkers for neurologic disorders. Neural degeneration increases with age and has the potential to confound the utility of NFs as biomarkers in the diagnosis of neurologic disorders. We investigated this relationship in horses with and without neurological diagnosis. While controlling for horse type (draft, pleasure, and racing), we evaluated the relationship between ser...
Toribio RE.Neonatal encephalopathy (NE) and neonatal maladjustment syndrome (NMS) are terms used for newborn foals that develop noninfectious neurologic signs in the immediate postpartum period. Cerebral ischemia, hypoxia, and inflammation leading to neuronal and glial dysfunction and excitotoxicity are considered key mechanisms behind NE/NMS. Attention has been placed on endocrine and paracrine factors that alter brain cell function. Abnormal steroid concentrations (progestogens, neurosteroids) have been measured in critically ill and NE foals. In addition to supportive treatment, antimicrobials should ...
Schmidt MJ, Knemeyer C, Heinsen H.In this study, the morphology of the horse brain (Equus caballus) is decribed in detail using high field MRI. The study includes sagittal, dorsal, and transverse T2-weighted images at 0.25 mm resolution at 3 Tesla and 3D models of the brain presenting the external morphology of the brain. Representative gallocyanin stained histological slides of the same brain are presented. The images represent a useful tool for MR image interpretation in horses and may serve as a starting point for further research aiming at in vivo analysis in this species.
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...
Perry S, Larhammar M, Vieillard J, Nagaraja C, Hilscher MM, Tafreshiha A, Rofo F, Caixeta FV, Kullander K.Neuronal networks within the spinal cord, collectively known as the central pattern generator (CPG), coordinate rhythmic movements underlying locomotion. The transcription factor doublesex and mab-3-related transcription factor 3 (DMRT3) is involved in the differentiation of the dorsal interneuron 6 class of spinal cord interneurons. In horses, a non-sense mutation in the gene has major effects on gaiting ability, whereas mice lacking the gene display impaired locomotor activity. Although the gene is necessary for normal spinal network formation and function in mice, a direct role for -deri...
Tanner J, Spriet M, Espinosa-Mur P, Estell KE, Aleman M.Temporohyoid osteoarthropathy is a well-recognized cause of equine neurologic disease. Temporal bone fractures associated with temporohyoid osteoarthropathy have been recognized with CT, however, little information is available regarding these fractures. The aims of this retrospective analytical study were to assess the prevalence of these fractures and to describe the specific configurations and associated imaging and clinical features. Fracture of the temporal bone was identified with CT in 16 of 39 included horses. All fractures were unilateral, minimally displaced and extended through the ...
Mittelman NS, Stefanovski D, Johnson AL.Accurate antemortem EPM diagnosis requires evidence of intrathecal antibody production. Some advocate the use of acute phase proteins in addition to serology, which alone results in substantial false positives. Objective: The purpose of this study was to determine if serum C-reactive protein (CRP) or serum amyloid A (SAA) concentrations were elevated in cases of equine protozoal myeloencephalitis (EPM) compared to other neurological diseases. Methods: 25 clinical cases of equine neurological disease: EPM (10), cervical vertebral stenotic myelopathy (CVSM) (10), neuroborreliosis (2), equine mot...
Ström L, Michanek M, Ekesten B.To investigate age-associated changes of flash visual evoked potentials (FVEPs) in sedated horses. Methods: Twenty-eight clinically healthy Standardbred Warmblooded trotters, aged 36 hours to 28 years. Methods: Light-adapted FVEPs and FERGs were recorded (An-vision RETIport, Roland-consult, Germany) in response to flash stimuli. Sedation was obtained using alpha-2-agonists intravenously. Akinesia of the eyelids was induced and pupils were dilated. Results: Reproducible FVEPs and FERGs were readily recorded from all foals and horses. The FVEP waveform included up to four positive components (...
Burns EN, Finno CJ.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy is an inherited neurodegenerative disorder affecting many horse breeds. Clinical signs include a symmetric ataxia and an abnormal stance at rest, similar to cervical vertebral compressive myelopathy, equine protozoal myeloencephalitis, and equine herpesvirus 1 myeloencephalopathy. This review will provide an update on the disease prevalence, management, impact, and ongoing research.
Finno CJ, Estell KE, Winfield L, Katzman S, Bordbari MH, Burns EN, Miller AD, Puschner B, Tran CK, Xu L.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on an α-tocopherol (α-TOH) deficient diet. Currently no antemortem diagnostic test for eNAD/EDM is available. Objective: Because α-TOH deficiency is associated with increased lipid peroxidation, it was hypothesized that F2 -isoprostanes (F2 IsoP), F4 -neuroprostanes (F4 NP) and oxysterols derived from free radical oxidation would be increased in the cerebrospinal fluid (CSF) and neural tissue of eNAD/EDM affected horses and could ...
Aleman M, Costa LRR, Crowe C, Kass PH.Neuroglycopenia refers to a shortage of glucose in the brain resulting in neuronal dysfunction and death if left untreated. Presumed neuroglycopenia has not been described in horses. Objective: To report neurological signs in horses with presumed neuroglycopenia as the result of severe hypoglycemia. Methods: Ninety horses (hours to 28 years of age) diagnosed with hypoglycemia (blood glucose concentration < 75 mg/dL [< 4.2 mmol/L]). Methods: Retrospective study. Electronic medical records were searched. Signalment, history, complaint, clinical signs, laboratory findings including CSF analysis, ...
Bell C, Hnenny L, Torske K.A 5-year-old Hannovarian warmblood gelding was presented for recurrent headshaking exacerbated with exercise. The horse displayed clinical signs of repetitive vertical head movements, face rubbing on the forelimbs and on the ground, repetitive sneezing, and striking the muzzle with his forelimbs. The clinical signs resulted in a horse that could not be ridden and was dangerous. Clinical signs were most persistent in direct sunlight, but occurred with excitement, exercise, or bridling indoors. A diagnosis of equine trigeminal mediated headshaking syndrome was made. Surgical treatment was perfor...
Hemmings A, Parker MO, Hale C, McBride SD.Spontaneous stereotypic behaviours are repetitive, compulsive, topographically invariant response patterns commonly observed in captive or domestic animals, which have been linked to dysfunction of basal ganglia input/output pathways. There is evidence that endogenous opioids play a key regulatory role in basal ganglia direct and indirect pathways, but their precise role, both causally and functionally, in spontaneous stereotypic behaviour is unclear. Here we examined the profile of mu- and delta-opioid receptors (density [Bmax] and affinity [Kd]) of basal ganglia structures in stereotypy (nâ€...
Farmer K, Krüger K, Byrne RW, Marr I.Many studies have been carried out into both motor and sensory laterality of horses in agonistic and stressful situations. Here we examine sensory laterality in affiliative interactions within four groups of domestic horses and ponies (N = 31), living in stable social groups, housed at a single complex close to Vienna, Austria, and demonstrate for the first time a significant population preference for the left side in affiliative approaches and interactions. No effects were observed for gender, rank, sociability, phenotype, group, or age. Our results suggest that right hemisphere specializ...
Rijckaert J, Pardon B, Van Ham L, van Loon G, Deprez P.To date, motor evoked potential (MEP) recording in animals is often performed using intramuscular monopolar needle electrodes. Their placement and use has several disadvantages. Adhesive surface electrodes appear to be attractive because they are painless and easy to place. Because these are not used in horses, a scouting study is performed to (1) explore the applicability of surface electrodes in horses (2) determine the repeatability of motor latency times (MLTs) and amplitude measurements, and (3) to investigate if MLTs and amplitude values of surface electrode recordings were similar to in...
Kang KD, Jung TW, Park IH, Han DH.Internet gaming disorder (IGD) has been suggested to be a mental health disorder. Attachment and emotional status in IGD patients are important for understanding the etiology and progression of IGD because both parameters are considered to be associated with the affective network. Equine-assisted activities and therapies (EAAT) have been reported to improve emotional status and attachment in subjects. We hypothesized that EAAT would improve attachment in IGD adolescents with insecure attachment issues and increase functional connectivity (FC) within the affective network. Methods: Subjects com...
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...
Johnson AL, Johnstone LK, Stefanovski D.The accuracy of the Lyme multiplex assay for the diagnosis of neuroborreliosis in horses is unknown. Objective: To describe Lyme multiplex results in horses with a postmortem diagnosis of neuroborreliosis. The hypothesis was that paired serum and cerebrospinal fluid (CSF) results and a CSFÂ :Â serum ratio would allow differentiation of horses with neuroborreliosis from those with other neurologic diseases. Methods: Ninety horses that had neurologic examinations, serum and CSF Lyme multiplex analyses, and postmortem examination of the nervous system performed. Methods: Retrospective study. Data...
Aman JE, Valberg SJ, Elangovan N, Nicholson A, Lewis SS, Konczak J.Cerebellar Purkinje cell axonal degeneration has been identified in horses with shivering but its relationship with abnormal hindlimb movement has not been elucidated. Objective: To characterise surface electromyographic (sEMG) hindlimb muscle activity in horses with shivering, correlate with clinical scores and examine horses for Purkinje axonal degeneration. Methods: Descriptive controlled clinical study. Methods: The hindlimb of seven shivering and six control draught horses were clinically scored. Biceps femoris (BF), vastus lateralis (VL), tensor fasciae latae and extensor digitorum longu...
McGorum BC, Pirie RS.Equine dysautonomia (ED; also known as equine grass sickness) is a neurological disease of unknown cause, which primarily affects grazing adult horses. The clinical signs reflect degeneration of specific neuronal populations, predominantly within the autonomic and enteric nervous systems, with disease severity and prognosis determined by the extent of neuronal loss. This review is primarily focused on the major clinical decision-making processes in relation to ED, namely, (1) clinical diagnosis, (2) selection of appropriate ancillary diagnostic tests, (3) obtaining diagnostic confirmation, (4)...
Al-Bagdadi F, Schumacher J, Carter J, Tóth F, Henry RW.The ramus communicans, neural connection between medial and lateral plantar nerves of the horse, was transected to determine the degree to which medial and lateral plantar nerves contribute to the plantar ramus. After 2 months, sections of plantar nerves immediately proximal and distal to the communicating branch were collected and processed for electron microscopy. All examined nerves had undergone Wallerian degeneration and contained regenerating and mature fibers. Layers of the myelin sheath were separated by spaces and vacuoles, indicating demyelination of medial and lateral plantar nerves...
Meneses CS, Müller HY, Herzberg DE, Uberti B, Werner MP, Bustamante HA.To determine the microglial and astrocyte response to painful lameness in horses. Methods: Ionized calcium binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) expression, cell density and morphology were determined through immunofluorescence within the dorsal horn of equine spinal cord. Methods: A total of five adult horses with acute or chronic unilateral lameness, previously scheduled for euthanasia. Methods: Musculoskeletal lameness was evaluated in five horses through visual evaluation according to clinical guidelines. Spinal cord samples were obtained immediately...
Scott EY, Woolard KD, Finno CJ, Penedo MCT, Murray JD.Cerebellar Abiotrophy (CA) is a neurodegenerative disease in Arabian horses affecting the cerebellum, more specifically the Purkinje neurons. Although CA occurs in several domestic species, CA in Arabian horses is unique in that a single nucleotide polymorphism (SNP) has been associated with the disease. Total RNA sequencing (RNA-seq) was performed on CA-affected horses to address the molecular mechanism underlying the disease. This research expands upon the RNA-seq work by measuring the impact of the CA-associated SNP on the candidate gene MutY homolog (MUTYH) and its regulation, isoform-spec...
Meneses CS, Müller HY, Herzberg DE, Uberti B, Bustamante HA, Werner MP.The role of glial cells in pain modulation has recently gathered attention. The objective of this study was to determine healthy spinal microglia and astrocyte morphology and disposition in equine spinal cord dorsal horns using Iba-1 and GFAP/Cx-43 immunofluorescence labeling, respectively. Five adult horses without visible wounds or gait alterations were selected. Spinal cord segments were obtained post-mortem for immunohistochemical and immunocolocalization assays. Immunodetection of spinal cord dorsal horn astrocytes was done using a polyclonal goat antibody raised against Glial Fibrillary ...
Myrna KE.This article provides a brief, clinically relevant review of neurologic disorders of the eye. A description of the neuro-ophthalmic examination is provided. Stepwise descriptions of the most common neuro-ophthalmic abnormalities are provided along with common rule outs.
Saville WJA, Reed SM, Dubey JP, Granstrom DE, Morley PS, Hinchcliff KW, Kohn CW, Wittum TE, Workman JD.The diagnosis of equine protozoal myeloencephalitis (EPM) relies heavily on the clinical examination. The accurate identification of neurologic signs during a clinical examination is critical to the interpretation of laboratory results. Objective: To investigate the level of agreement between board-certified veterinary internists when performing neurologic examinations in horses. Methods: Ninety-seven horses admitted to the Veterinary Teaching Hospital at The Ohio State University from December 1997 to June 1998. Methods: A prospective epidemiologic research design was used. Horses enrolled in...
Timoney PJ, Donnelly WJ, Clements LO, Fenlon M.An outbreak of LI infection in a group of free range horses is described. Three of 4 horses displayed signs of CNS disturbance and 2 of these died after illnesses ranging from 2-12 days duration. In both cases a variable degree of viral polioencephalomyelitis was observed. A virus antigenically indistinguishable from a reference strain of LI virus was isolated from the brain and cervical cord of a 3 y.o. draft mare. Serum samples obtained from 3 of the horses contained HI, CF, precipitating and neutralising antibodies to LI virus, with a rise in antibody titre being demonstrated in 2 animals.
Gundlach AL, Kortz G, Burazin TC, Madigan J, Higgins RJ.Inherited myoclonus in Poll Hereford calves and spasticity in the spastic mouse (spa/spa) are characterized by myoclonic jerks of the skeletal musculature which occur spontaneously and in response to sensory stimuli, symptoms resembling those in subconvulsive strychnine poisoning. The primary, biochemical defect in these myoclonic animals is a deficit of inhibitory glycine receptors in the central nervous system. We now report the occurrence of similar stimulus-induced myoclonus in individual, pure-bred Peruvian Paso horses and an associated, specific deficiency in the density of [3H]strychnin...
Otto K, Short CE.Electroencephalographic (EEG) power spectrum analysis was performed in 18 conscious, adult horses for evaluation as control values for EEG data obtained during anesthesia. Computer-processed total amplitudes for the frequency range 0 to 32 Hz were mainly between 400 and 600 microV, with 80% spectral edge frequency between 16.6 and 32.5 Hz. The highest electrical activity was in the delta band (41.3 +/- 4.4% of total amplitude); there was a less pronounced activity in the beta (34.2 +/- 5.2%), theta (13.6 +/- 1.5%), and alpha (10.0 +/- 1.0%) bands. The applicability of EEG power spectrum analys...
Chiocchetti R, Bombardi C, Mongardi-Fantaguzzi C, Venturelli E, Russo D, Spadari A, Montoneri C, Romagnoli N, Grandis A.This paper describes the morphology and distribution of the enteric nervous system (ENS) cells and fibres immunoreactive for choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), substance P (SP), calcitonin gene-related peptide (CGRP), NF200kDa (NF200), and S100 protein. The percentages of subclasses of enteric neurons in the total neuronal population were investigated by the use of anti-PGP 9.5 or anti-NSE antibodies. ChAT-IR myenteric plexus (MP) and submucosal plexus (SMP) neurons were 66+/-7% and 74+/-15%, respectively, whereas those cells expressing nNOS-IR were 38+/-7...
Laval K, Van Cleemput J, Poelaert KC, Brown IK, Nauwynck HJ.Equine herpesvirus type 1 (EHV-1) is responsible for respiratory disorders, abortion and myeloencephalopathy (EHM) in horses. Two pathotypes of EHV-1 strains are circulating in the field: neurovirulent (N) and non-neurovirulent (NN). For both strains, CD172a monocytic cells are one of the main carrier cells of EHV-1 during primary infection, allowing the virus to invade the horse's body. Recently, we showed that EHV-1 NN strains showed a restricted and delayed replication in CD172a cells. Here we characterize the in vitro replication kinetics of two EHV-1N strains in CD172a cells and investiga...
Foss RR, Genetzky RM, Riedesel EA, Graham C.Two horses with ataxia of all four limbs were found to have cervical intervertebral disc protrusion. Severe pelvic limb ataxia, proprioceptive deficits and spasticity were present in both horses with similar but less severe signs in the thoracic limbs. Cerebrospinal fluid analysis was within normal limits. Metrizamide myelography allowed definitive diagnosis in one case when a compression of the spinal cord was demonstrated at the level of the second intervertebral space. In the second case, an intervertebral disc protrusion between cervical vertebrae 6 and 7 was found at necropsy. Fiber degen...
Giancola F, Rambaldi AM, Bianco F, Iusco S, Romagnoli N, Tagliavia C, Bombardi C, Clavenzani P, De Giorgio R, Chiocchetti R.Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5-HT exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5-HT agonists is well known, the cellular sites of 5-HT expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5-HT in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprung's disease. Methods: The intestine and spinal ganglia were obtained from three he...
Tong L, Stewart M, Johnson I, Appleyard R, Wilson B, James O, Johnson C, McGreevy P.The current project aims to build on knowledge of the nociceptive capability of equine skin to detect superficial acute pain, particularly in comparison to human skin. Post-mortem samples of gluteal skin were taken from men ( = 5) and women ( = 5), thoroughbreds and thoroughbred types (mares, = 11; geldings, = 9). Only sections that contained epidermis and dermis through to the hypodermis were analysed. Epidermal depth, dermal depth and epidermal nerve counts were conducted by a veterinary pathologist. The results revealed no significant difference between the epidermal nerve counts of human...
Chang HJ, Jung YG, Park YS, O SH, Kim DH, Kim CW.The horse riding simulator (HRS) reportedly has a beneficial effect on motor function and balance in children with cerebral palsy (CP). However, by itself, the HRS is not a sufficient source of challenge and motivation for children. To address this issue, we combined the HRS with virtual reality (VR) to promote somatosensory stimulation and motivation. Sixteen children (ages: 5-17 years) with CP and presenting Gross Motor Function Classification System (GMFCS) levels I-IV were enrolled in the study. Using a head-mounted display and controllers, interventions were carried out over 30-min period...
Pezzanite LM, Easley JT, Bayless R, Aldrich E, Nelson BB, Seim HB, Nout-Lomas YS.Further development of surgical techniques for equine cervical stabilisation is necessary to make the procedure less technically demanding, reduce complications and improve outcomes. Objective: To describe clinical outcomes and owner reports in horses undergoing placement of an interbody fusion device and polyaxial pedicle screw and rod construct for cervical vertebral fusion in horses with cervical vertebral compressive myelopathy. Methods: Retrospective case series. Methods: Data were retrieved from medical records of 10 horses undergoing cervical vertebral fusion (2015-2019). Records were e...
Pownder S, Scrivani PV, Bezuidenhout A, Divers TJ, Ducharme NG.In people, specific classifications of temporal bone fractures are associated with clinical signs and prognosis. In horses, similar classifications have not been evaluated and might be useful establishing prognosis or understanding pathogenesis of certain types of trauma. Objective: We hypothesized associations between temporal bone fracture location and orientation in horses detected during computed tomography (CT) and frequency of facial nerve (CN7) deficit, vestibulocochlear nerve (CN8) deficit, or temporohyoid osteoarthropathy (THO). Complex temporal region anatomy may confound fracture id...
Marshall AE, Byars TD, Whitlock RH, George LW.Brainstem auditory evoked response (BAER) testing was done to evaluate inner ear/VIIIth cranial nerve (CN8) function in the horse. The BAER test consisted of stimulating the auditory system with clicks and recording far-field responses of the brainstem auditory components via cutaneous electrodes and a signal averaging system. The normal response was shown to be a series of waves occurring within the first 10 msec after the stimulus click. Functional loss of the auditory receptor organ (cochlea) or CN8 results in loss of the entire response on the side of the injury. Because of the anatomic re...
Ferrell EA, Gavin PR, Tucker RL, Sellon DC, Hines MT.Magnetic resonance (MR) imaging was used as a neurodiagnostic modality in the assessment of 12 horses with neurologic disease localized cranial to the foramen magnum. This retrospective study included a mixed population of horse breeds and consisted of three foals and nine adult horses. MR sequences of the head and central nervous system of each horse were acquired. Routine MR sequences included transverse T1 weighted (T1wt), T2 weighted (T2wt), and proton density images. Additional imaging sequences were obtained on a patient-dependent basis. Eight neurologic related diseases were diagnosed. ...
Giessler KS, Samoilowa S, Soboll Hussey G, Kiupel M, Matiasek K, Sledge DG, Liesche F, Schlegel J, Fux R, Goehring LS.Upper respiratory tract infections with Equid Herpesvirus 1 (EHV-1) typically result in a peripheral blood mononuclear cell-associated viremia, which can lead to vasculopathy in the central nervous system. Primary EHV-1 infection also likely establishes latency in trigeminal ganglia (TG) via retrograde axonal transport and in respiratory tract-associated lymphatic tissue. However, latency establishment and reactivation are poorly understood. To characterize the pathogenesis of EHV-1 latency establishment and maintenance, two separate groups of yearling horses were experimentally infected intra...
Zamboulis DE, Senior JM, Clegg PD, Gallagher JA, Carter SD, Milner PI.Purinergic pathways are considered important in pain transmission, and P2X receptors are a key part of this system which has received little attention in the horse. The aim of this study was to identify and characterise the distribution of P2X receptor subtypes in the equine digit and associated vasculature and nervous tissue, including peripheral nerves, dorsal root ganglia and cervical spinal cord, using PCR, Western blot analysis and immunohistochemistry. mRNA signal for most of the tested P2X receptor subunits (P2X1-5, 7) was detected in all sampled equine tissues, whereas P2X6 receptor su...
Firląg M, Kamaszewski M, Gaca K, Bałasińska B.Aging is a process which operates at many levels of physiological, genetic and molecular organization and leads inevitably to death. Brain macroscopic changes by MRI investigation during aging were observed in humans and dogs but chimpanzees did not display significant changes. This suggestion led to the statement that brain aging is different in various species. Although human brain changes, e.g. β-amyloid storage, neurofibrillary tangle formation, lipofuscin, are relatively well known, we are still looking for a suitable animal model to study the mechanisms of aging and neurodegenerative di...
de Camp NV, Ladwig-Wiegard M, Geitner CIE, Bergeler J, Thöne-Reineke C.As has been hypothesized more than 20 years ago, data derived from Electroencephalography (EEG) measurements can be used to distinguish between behavioral states associated with animal welfare. In our current study we found a high degree of correlation between the modulation index of phase related amplitude changes in the EEG of horses ( = 6 measurements with three different horses, mare and gelding) and their facial expression, measured by the use of the horse grimace scale. Furthermore, the pattern of phase amplitude coupling (PAC) was significantly different between a rest condition and a s...
Science (New York, N.Y.)November 5, 1976
Volume 194, Issue 4265 626-627 doi: 10.1126/science.790567
Radinsky L.Previous interpretations of early horse brains were based on an incorrectly identified fossil endocast, now believed to be from a condylarth. Newly prepared endocasts of Hyracotherium, the oldest horse and one of the earliest perissodactyls, reveal a relatively larger brain, with a more expanded neocortex, than existed in the condylarth ancestors of perissodactyls. Fifty million years ago, horse brains had suprasylvian, ectolateral, and lateral sulci, but the frontal lobe was undeveloped.
Tanner J, Spriet M, Espinosa-Mur P, Estell KE, Aleman M.Temporohyoid osteoarthropathy is a well-recognized cause of equine neurologic disease. Temporal bone fractures associated with temporohyoid osteoarthropathy have been recognized with CT, however, little information is available regarding these fractures. The aims of this retrospective analytical study were to assess the prevalence of these fractures and to describe the specific configurations and associated imaging and clinical features. Fracture of the temporal bone was identified with CT in 16 of 39 included horses. All fractures were unilateral, minimally displaced and extended through the ...
Duncan ID, Reifenrath P, Jackson KF, Clayton M.The terminal branches of the recurrent laryngeal nerve (RLN) of three normal ponies and six horses with sub-clinical laryngeal disease were examined qualitatively and quantitatively in an attempt to explain the preferential denervation of the laryngeal adductor muscles in the neuropathy of idiopathic laryngeal hemiplegia (ILH). The myelinated fibre spectra of all the motor nerve fibres in the left and right abductor and adductor branches of the RLN in three normal ponies were measured. The density of myelinated fibres was also calculated. There was no significant difference between the larger ...
Spadavecchia C, Arendt-Nielsen L, Andersen OK, Spadavecchia L, Doherr M, Schatzmann U.To compare nociceptive withdrawal reflexes (NWRs) evoked from the distal aspect of the left forelimb and hind limb in conscious standing horses and to investigate NWR recruitment for graded electrical stimulation intensities. Methods: 20 adult horses. Methods: Surface electromyographic (EMG) activity evoked by transcutaneous electrical stimulation of the digital palmar (or plantar) nerve was recorded from the common digital extensor and cranial tibial muscles. Stimuli consisted of 25-millisecond train-of-5 constant current pulses. Current intensity was gradually increased until NWR threshold i...
Eagle RC, Font RL, Swerczek TW.An 18-month-old Standardbred filly had a large intraocular tumor involving the optic nerve. The tumor was a malignant medulloepithelioma, a rare intraocular neoplasm derived from the primitive medullary epithelium. By light microscopy the tumor had cords and lobules of primitive neuroepithelial cells that formed clefts and true rosettes. Electron microscopy of the rosettes showed a girdle of zonulae adherentes joining the apices of the cells as well as several basal bodies. This is the sixth report of equine intraocular medulloepithelioma, and, to the best of our knowledge, the first intraocul...
Cruz Villagrán C, Amelse L, Neilsen N, Dunlap J, Dhar M.Mesenchymal stromal cells (MSCs) are able to differentiate into extramesodermal lineages, including neurons. Positive outcomes were obtained after transplantation of neurally induced MSCs in laboratory animals after nerve injury, but this is unknown in horses. Our objectives were to test the ability of equine MSCs to differentiate into cells of neural lineage in vitro, to assess differences in morphology and lineage-specific protein expression, and to investigate if horse age and cell passage number affected the ability to achieve differentiation. Bone marrow-derived MSCs were obtained from yo...
Parker M, McBride SD, Redhead ES, Goodwin D.Significant similarities exist between the neural and behavioural features of environmentally and drug-induced stereotypy. For example, exposure to dopamine agonists, such as amphetamine, induces stereotypy and causes alterations in midbrain neurophysiology similar to those observed following chronic stress. An additional behavioural feature of these neural changes in the drug-induced phenotype is an enhanced rate of switching from response-outcome (R-O) to stimulus-response (S-R) learning. The aim of the current experiment was to examine R-O and S-R learning in horses displaying environmental...
Prieto D, Benedito S, Rodrigo J, MartÃnez-Murillo R, GarcÃa-Sacristán A.The distribution and density of neuropeptide Y (NPY)-immunoreactive nerve fibres and cells were determined in the urinary bladder of the horse by using the peroxidase-antiperoxidase (PAP) immunohistochemical method. Numerous undulating NPY-immunoreactive nerve fibres were found throughout the vesical wall, sometimes forming nerve bundles which ramified repeatedly as they coursed through the connective tissue septa to give rise to smaller bundles or single fibres which projected into the muscle fascicles forming muscular nerve plexuses, mainly in the bladder base. In the submucosa of this regio...
Mohammed HO, Starkey SR, Stipetic K, Divers TJ, Summers BA, de Lahunta A.Our previous studies implicated vitamin E deficiency as a risk factor for equine motor neuron disease, a possible model of human amyotrophic lateral sclerosis, and showed direct effects of this deficiency on brain vascular endothelium. To gain better understanding of the pathogenesis of equine motor neuron disease, we determined the effects of dietary antioxidant insufficiency and the resultant brain tissue oxidative stress on blood-brain barrier permeability. Rats (n = 40) were maintained on a diet deficient of vitamin E for 36 to 43 weeks; 40 controls were fed a normal diet. Permeability of ...
