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.
Nessler JN, Delarocque J, Kloock T, Twele L, Neudeck S, Meyerhoff N, Riese F, Cavalleri JV, Tipold A, Feige K, Niebuhr T.To determine whether sensory nerve conduction stimulus threshold measurements of the infraorbital nerve are able to differentiate horses with idiopathic trigeminal-mediated headshaking (i-TMHS) from healthy horses and from horses with secondary trigeminal-mediated headshaking (s-TMHS). In a prospective trial, headshaking horses were examined using a standardized diagnostic protocol, including advanced diagnostics such as computed tomography and 3-Tesla-magnetic resonance imaging (MRI), to differentiate s-TMHS from i-TMHS. Clinically healthy horses served as controls. Within this process, patie...
Morris J, Hoang D.This article discusses a rare case of isolated xylazine overdose in a human, treated successfully with naloxone. Xylazine, typically used as a veterinary tranquilizer, acts as a potent α2 adrenergic agonist, leading to sedation, muscle relaxation, and potential respiratory depression. In this case, a female mistakenly injected herself with xylazine mistaking it for a different medication. The report discusses naloxone's role beyond opioid overdose, especially regarding substances causing central nervous system (CNS) depression via mechanisms similar to those of opioids. While naloxone is trad...
Ignacio C, Del Mar LM, Marta B, Sina Z, Vicent R, Aloma MF.In modern times, horses are utilized not only for labour and transportation purposes but also for recreational activities such as competition and pleasure riding. In these various pursuits, the role of vision plays a crucial role. Electroretinography is the most used test to diagnose diseases of the retinal outer segment. There is a wide variety of devices to perform the electroretinography differing one from each other in the corneal electrode and the light stimulation. The Koijman electrode has been tested in dogs but not in horses. The main purpose of this study was to compare electroretino...
Rogers LJ.The specialized functions of each hemisphere of the vertebrate brain are summarized together with the current evidence of lateralized behavior in farm and companion animals, as shown by the eye or ear used to attend and respond to stimuli. Forelimb preference is another manifestation of hemispheric lateralization, as shown by differences in behavior between left- and right-handed primates, left- and right-pawed dogs and cats, and left- and right-limb-preferring horses. Left-limb preference reflects right hemisphere use and is associated with negative cognitive bias. Positive cognitive bias is ...
Cheng X, Qian L, Fan Y, Tang Q, Wu H.Inhibitory control (IC), an important component of executive function, plays an important role in the overall development of children and has not been better studied in the field of equine-assisted activity (EAA). Therefore, this study investigated the effects of EAA on IC and the underlying brain neural mechanisms in children aged 7-8 years. Conclusions: Collectively, EAA demonstrated a positive impact on IC and could effectively activate R-DLPFC in children aged 7-8 years. Furthermore, it enhanced the activation of the brain regions related to IC and increased cognitive ability in children a...
Greening L, Allen S, McBride S.Sleep disturbance is observed across species, resulting in neurocognitive dysfunction and poor impulse control/regulation of negative emotion. Understanding animal sleep disturbance is thus important to understand how environmental factors influence animal sleep and day-to-day welfare. Self-reporting tools for sleep disturbance are commonly used in human research to determine sleep quality, that cannot be transferred to non-verbal animal species research. Human research has, however, successfully used frequency of awakenings to create an objective measurement of sleep quality. The aim of this ...
Seki N, Tochinai R, Sekizawa SI, Márquez MA, Fukuda K, Ohmura H, Kuwahara M.The Criollo is an Argentine horse breed with a calm temperament. Although its temperament is considered to be related to its neurophysiological characteristics, the details of this are unknown. Therefore, we analyzed the heart rate variability in Criollos as a preliminary study to deepen the neurophysiological understanding of their autonomic function. Electrocardiograms were recorded from Criollos and Thoroughbreds, and the power spectrum of heart rate variability was analyzed. Compared with Thoroughbreds, Criollos showed (i) a significantly higher high-frequency component, which is an index ...
Harvey AM, Beausoleil NJ, Ramp D, Mellor DJ.The mental experiences of animals are what characterises their welfare status. The Five Domains Model for assessing welfare aligns with the understanding that physical and mental states are linked. Following measurement of indicators within each of the four physical/functional Domains (1. Nutrition; 2. Physical environment; 3. Health; and 4. Behavioural interactions), the anticipated negative or positive affective consequences (mental experiences) are cautiously inferred and assigned to Domain 5. Those inferences derive credibility from validated knowledge of the underlying systems of physiolo...
Vinardell T, Elestwani S, Jamieson C, Karim E, Robin M, Glynn S, Benini R, Aleman M.A standardized protocol for electroencephalography (EEG) under standing sedation for the investigation of epilepsy in foals is needed. Objective: To evaluate a modified standardized EEG protocol under standing sedation using sublingual detomidine hydrochloride in Egyptian Arabian foals. Methods: Nineteen foals (controls, 9; juvenile idiopathic epilepsy [JIE], 10). Methods: Descriptive clinical study. Foals were classified as controls or epileptic based on history or witnessed seizures and neurological examination. Foals were sedated using sublingual detomidine hydrochloride at a dosage of 0.08...
Phelps S, Chong D, McKenzie E, Kiupel M, Gorman E.Clinical disease caused by infection with Listeria monocytogenes is rare in adult horses, and there is a paucity of ante-mortem clinicopathologic changes for this species reported in the literature. Confirmatory diagnosis is difficult and often requires post-mortem sampling of the brainstem. This report details a case of meningoencephalitis caused by Listeria monocytogenes in an adult American quarter horse gelding presenting with central neurologic signs. Pre-mortem analysis of the cerebrospinal fluid revealed a mononuclear, primarily lymphocytic, pleocytosis, which is a reported finding in o...
Salamanca-Carreño A, Parés-Casanova PM, Crosby-Granados RA, Vélez-Terranova M, Bentez-Molano J.The skull is divided into neurocranium and splanchnocranium, and its variation allows ecomorphological studies to learn about possible evolutionary and adaptive characteristics. The basicranial organization of the neurocranium and splanchnocranium modules was studied in a sample of 31 skulls from adult Araucanian horses by means of 2D geometric morphometric techniques. The neurocranium and splanchnocranium modules on the ventral aspect were analyzed separately using a set of 31 landmarks. The RV coefficient (the multivariate analog of a correlation) was estimated to analyze the independence of...
Trobec T, Žužek MC, Sepčić K, Kladnik J, Turel I, Frangež R.Enzyme butyrylcholinesterase (BChE) shows increased activity in some brain regions after progression of Alzheimer's disease and is therefore one of the therapeutic targets for symptomatic treatment of this neurodegenerative disorder. The organoruthenium(II) complex [(η--cymene)Ru(II)(1-hydroxy-3-methoxypyridine-2(1)-thionato)pta]PF () was designed based on the results of our previous structure-activity studies. Inhibitory activity toward cholinesterase enzymes shows that this complex selectively, competitively, and reversibly inhibits horse serum BChE (hsBChE) with an IC value of 2.88 µM. Wh...
Donnelly CG, Finno CJ.Phosphorylated neurofilament heavy, a marker of neuroaxonal damage, is increased in horses with equine neuroaxonal dystrophy. However, the temporal dynamics of this biomarker during the post-natal risk period are not understood. Objective: To measure serum and cerebrospinal fluid phosphorylated neurofilament heavy concentrations in juvenile foals across the post-natal window of susceptibility for equine neuroaxonal dystrophy. Methods: Case-control in vivo experimental study. Methods: Concentrations of phosphorylated neurofilament heavy were measured using frozen serum and cerebrospinal fluid c...
Hansen S, Olsen E, Raundal M, Agerholm JS.Cerebellar abiotrophy (CA) is an uncommon hereditary neurodegenerative disorder affecting the cerebellar Purkinje cells. Equine CA has been reported in several breeds, but a genetic etiology has only been confirmed in the Arabian breed, where CA is caused by an autosomal recessive mutation. Methods: Clinical and histological findings consistent with CA are reported in an 8.5-month-old Icelandic filly. The filly showed a perceived sudden onset of marked head tremor, incoordination, ataxia, lack of menace response and a broad-based stance. Cerebrospinal fluid, hematological and biochemical findi...
Murillo C, Weng HY, Weil AB, Kreuzer M, Ko JC.This study aimed to investigate the use of electroencephalography (EEG) for detecting brain activity changes perioperatively in anesthetized horses subjected to surgery. Twelve adult horses undergoing various surgeries were evaluated after premedication with xylazine and butorphanol, induction with ketamine, midazolam, and guaifenesin, and maintenance with isoflurane. The frontal EEG electrodes were placed after the horse was intubated and mechanically ventilated. The EEG data were collected continuously from Stage (S)1-transition from induction to isoflurane maintenance, S2-during surgery, S3...
Repac J, Mangan E, Xie H.Acupuncture is an inexpensive nonpharmacological modality that has a variety of musculoskeletal, neurologic, and internal medicine applications for the equine practitioner. Common uses include back pain colic, laminitis, laryngeal hemiplegia, and suprascapular neuropathy. Although there is a growing body of literature supporting the use of acupuncture in equids, there remains a need for further robust, double-blinded, placebo-controlled clinical efficacy trials.
Cahalan SD, Perkins JD, Boehm I, Jones RA, Gillingwater TH, Piercy RJ.Morphological study of the neuromuscular junction (NMJ), a specialised peripheral synapse formed between a lower motor neuron and skeletal muscle fibre, has significantly contributed to the understanding of synaptic biology and neuromuscular disease pathogenesis. Rodent NMJs are readily accessible, and research into conditions such as amyotrophic lateral sclerosis (ALS), Charcot-Marie-Tooth disease (CMT), and spinal muscular atrophy (SMA) has relied heavily on experimental work in these small mammals. However, given that nerve length dependency is an important feature of many peripheral neurop...
Hahn C.The neurological examination is undertaken to determine whether any deficit is due to a lesion in the nervous system and, if so, where within the nervous system any possible lesion or lesions are located. The examination of horses has challenges not encountered when doing the equivalent examination in dogs and cats, principally that spinal reflexes and postural reactions are impossible/difficult to assess in most animals. The anatomy book can be consulted later but at the end of the neurological examination the clinician then should be able to determine broadly which area of the neuromuscular ...
Schils S, Ober T.When diagnosing neuromuscular injury and pain, the use of biomechanical evaluations to assess the mechanics of movement patterns has been useful in the human population. Functional electrical stimulation (FES) is a technology that can create action potentials to produce musculoskeletal movement that is almost indistinguishable from the voluntary kinematics produced by the nervous system. To create controlled and precise musculoskeletal movements in humans and in horses, FES has been shown to be effective. In humans, the kinematic information obtained from FES data has been utilized to direct f...
Nout-Lomas YS.Mechanisms of traumatic nervous system injury to a degree are similar, but differences exist in etiology, pathophysiology, and treatment of brain, spinal cord, and peripheral nerve injury. The most common clinical abnormalities seen in the horse are abnormal level of consciousness, abnormal behavior, seizures, cranial nerve deficits, vestibular disease, tetra- and paraparesis or paraplegia, cauda equina syndrome, specific gait deficits, and muscle atrophy. Treatments are directed toward reducing inflammation and swelling, halting secondary injury, and promoting mechanisms of neuroregeneration ...
Valberg SJ.Movement disorders are defined as involuntary movements that are not due to a painful stimulus or associated with changes in consciousness or proprioception. Diagnosis involves ruling out any lameness and neurologic disease and characterizing the gait during walking backward and forward and trotting. Shivers causes abnormal hindlimb hypertonicity during walking backward and, when advanced, a few strides walking forward. Stringhalt causes consistent hyperflexion during walking forward and trotting and variable difficulty when walking backward. Classification and potential causes are discussed a...
Garrett KS.Diagnostic imaging is often an important part of the diagnostic approach to neurologic disease. Advanced imaging techniques such as myelography, computed tomography (CT), and magnetic resonance imaging (MRI) provide more information than radiography and ultrasonography but are more limited in their availability. The clinician should be cognizant of the findings of the clinical examination when interpreting diagnostic imaging findings.
Aleman M.The vestibular system (VS) is the primary specialized sensory system responsible for maintaining balance (equilibrium) and orientation of the eyes, neck, trunk, and limbs during rest and movement. Two important reflexes are responsible for maintaining balance: vestibulo-ocular and vestibulospinal reflexes. These reflexes involve peripheral and central components of the VS. Whether central or peripheral disease, most of the disorders of the VS result in ipsilateral neurologic deficits. A few uncommon exceptions present with contralateral signs to the site of the lesion. This article provides a ...
Journée HL, Journée SL.Depending on the localization of the lesion, spinal cord ataxia is the most common type of ataxia in horses. Most prevalent diagnoses include cervical vertebral stenotic myelopathy (CVSM), equine protozoal myeloencephalitis (EPM), trauma and equine degenerative myeloencephalopathy (EDM). Other causes of ataxia and weakness are associated with infectious causes, trauma and neoplasia. A neurologic examination is indispensable to identify the type of ataxia. In addition, clinical neurophysiology offers tools to locate functional abnormalities in the central and peripheral nervous system. Clinical...
MacKay RJ, Howe DK.Advances in the understanding of equine protozoal myeloencephalitis (EPM) are reviewed. It is now apparent that EPM can be caused by either of 2 related protozoan parasites, Sarcocystis neurona and Neospora hughesi, although S neurona is the most common etiologic pathogen. Horses are commonly infected, but clinical disease occurs only infrequently; the factors influencing disease occurrence are not well understood. Epidemiologic studies have identified risk factors for the development of EPM, including the presence of opossums and prior stressful health-related events. Attempts to reproduce EP...
Johnson SA.Rehabilitation of the neurologic horse represents a unique challenge for the equine practitioner. Improving postural stability and balance control through improving the strength of the spinal stabilizer muscle multifidus remains one of the most promising rehabilitative targets. This muscle can be targeted through the use of physiotherapeutic exercises, various forms of perturbation, and even whole-body vibration. Neuroanatomic localization and diagnosis specificity enable the practitioner to determine suitability for such rehabilitative tasks, and with the advent of evolving strategies and com...
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.
Rojas-Núñez I, Gomez AM, Palmer S, Mohammed HO.Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in inju...
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...
Adalbert R, Cahalan S, Hopkins EL, Almuhanna A, Loreto A, Pór E, Körmöczy L, Perkins J, Coleman MP, Piercy RJ.Neurological disorders are prevalent in horses, but their study is challenging due to anatomic constraints and the large body size; very few host-specific in vitro models have been established to study these types of diseases, particularly from adult donor tissue. Here we report the generation of primary neuronal dorsal root ganglia (DRG) cultures from adult horses: the mixed, dissociated cultures, containing neurons and glial cells, remained viable for at least 90 days. Similar to DRG neurons in vivo, cultured neurons varied in size, and they developed long neurites. The mitochondrial movem...
Mayhew IG.Methods for atlanto-occipital and lumbosacral collection of cerebrospinal fluid from the horse are described in detail, and the techniques and complications discussed.
Simonsen U, Prieto D, Sánez de Tejada I, García-Sacristán A.1. The involvement of nitric oxide (NO) and the signal transduction mechanisms mediating neurogenic relaxations were investigated in deep intracavernous penile arteries with an internal lumen diameter of 600-900 microns, isolated from the corpus cavernosum of young horses. 2. The presence of nitric oxide synthase (NOS)-positive nerves was examined in cross and longitudinal sections of isolated penile arteries processed for NADPH-diaphorase (NADPH-d) histochemistry. NADPH-d-positive nerve fibres were observed in the adventitia-media junction of deep penile arteries and in relation to the trabec...
Dickey EJ, Long SN, Hunt RW.Hypoxic ischemic encephalopathy (HIE) is a condition that occurs in both human newborns and foals. The condition is the subject of extensive current research in human infants, but there have been no direct studies of HIE in foals, and hence, knowledge of the condition has been extrapolated from studies in humans and other animal models. The purpose of this review article is to highlight the most up-to-date and relevant research in the human field, and discuss how this potentially might have an impact in the management of foals with HIE.
Wright JD, Kelly WR, Waddell AH, Hamilton J.Verminous encephalomyelitis due to Angiostrongylus cantonensis larvae was diagnosed in 2 foals at necropsy. The principal clinical feature was tetraparesis, although history and neurological examination revealed progressive and multifocal neurological disease. At presentation, a tentative diagnosis of parasitic larval migration involving the central nervous system (CNS), presumably due to Strongylus vulgaris, was proposed. Dissection of the spinal cord in one case resulted in recovery of intact larvae of both sexes of A. cantonensis. In both foals, histopathology of the brain and spinal cord r...
Deeg CA, Amann B, Lutz K, Hirmer S, Lutterberg K, Kremmer E, Hauck SM.Müller glial cells are important regulators of physiological function of retina. In a model disease of retinal inflammation and spontaneous recurrent uveitis in horses (ERU), we could show that retinal Müller glial cells significantly change potassium and water channel protein expression during autoimmune pathogenesis. The most significantly changed channel protein in neuroinflammatory ERU was aquaporin 11 (AQP11). Aquaporins (AQP, 13 members) are important regulators of water and small solute transport through membranes. AQP11 is an unorthodox member of this family and was assigned to a thi...
Whishaw IQ, Sacrey LA, Gorny B.An animal that has stepped over an obstacle with its forelimbs uses a memory of the obstacle to guide the hind limbs so that they also clear the obstacle, even in situations in which long pauses are introduced between forelimb and hind limb stepping. To further clarify the features of hind limb obstacle clearance memory, the present study examined hind limb obstacle clearance in the horse. A rider guided horses over obstacles and paused the horse over obstacles in tests that examined the relationship between forelimb and hind limb stepping, with the following results. First, the horses display...
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.
Hermosilla C, Coumbe KM, Habershon-Butcher J, Schöniger S.A fatal case of eosinophilic and granulomatous meningoencephalitis caused by the free-living panagrolaimid nematode Halicephalobus gingivalis is reported in a 10-year-old Welsh gelding in the United Kingdom. Clinical examination first revealed behavioural abnormalities which rapidly progressed to severe ataxia, reduced mentation status and cranial nerve signs. Despite symptomatic treatment no amelioration of neurological signs was achieved and the horse was subjected to euthanasia. A complete post mortem examination revealed eosinophilic and granulomatous meningoencephalitis mainly affecting t...
Johnson PJ, Janvier V, Luh WM, FitzMaurice M, Southard T, Barry EF.There is growing interest in the horse for behavioral, neuroanatomic and neuroscientific research due to its large and complex brain, cognitive abilities and long lifespan making it neurologically interesting and a potential large animal model for several neuropsychological diseases. Magnetic resonance imaging (MRI) is a powerful neuroscientific research tool that can be performed , with adapted equine facilities, or in the research setting. The brain atlas is a fundamental resource for neuroimaging research, and have been created for a multitude animal models, however, none currently exist f...
Hyun GJ, Jung TW, Park JH, Kang KD, Kim SM, Son YD, Cheong JH, Kim BN, Han DH.Equine-assisted activity and training (EAAT) is thought to improve body balance and clinical symptoms in children with attention deficit hyperactivity disorder (ADHD). The study hypostheses were that EAAT would improve the clinical symptoms and gait balance in children with ADHD and that these improvements would be associated with increased brain connectivity within the balance circuit. Methods: A total of 12 children with ADHD and 12 age- and sex-matched healthy control children were recruited. EAAT consisted of three training sessions, each 70 minutes long, once a week for 4 weeks. Brain fun...
Borchers K, Wolfinger U, Ludwig H.Equine herpesvirus type 4 (EHV-4) is a major respiratory pathogen of horses. Unlike most other members of the Alphaherpesvirinae, EHV-4 was regarded as non-neurotropic. Here, neural and lymphoid tissues of 17 horses have been analysed post-mortem. EHV-4 DNA was detected in 11 cases (65%) by PCR, exclusively in the trigeminal ganglia. In order to define the transcriptional activity, RNA preparations of 10 EHV-4 DNA-positive ganglia were investigated by nested RT-PCR. EHV-4-specific transcripts derived from genes 63 [herpes simplex virus type 1 (HSV-1) ICPO gene homologue] and 64 (HSV-1 ICP4 gen...
Stankov B, Cozzi B, Lucini V, Fumagalli P, Scaglione F, Fraschini F.Melatonin receptors were characterized in the brains of three mammals (rabbit, horse and sheep) by an in vitro binding technique, using 2-[125I]iodomelatonin as labelled ligand. Although binding sites for melatonin have been described recently in several vertebrate species (including the sheep), the rabbit and the horse have not been the subject of investigation so far. Apart from characterization, the present report describes receptor distribution in a number of brain regions, thus allowing for direct interspecies comparison under the same methodological conditions. 2-[125I]iodomelatonin labe...
Gibson SJ, Polak JM, Anand P, Blank MA, Morrison JF, Kelly JS, Bloom SR.The distribution of VIP-immunoreactivity was studied in the spinal cord and dorsal root ganglia of 6 mammalian species. Immunoreactive fibres and cell bodies were most apparent in the dorsal horn, dorsolateral funiculus, intermediolateral cell columns and the area around the central canal. The distribution of VIP immunoreactivity was similar in all species studied, mouse, rat, guinea pig, cat, horse and the marmoset monkey. There were fewer VIP fibres in the dorsal horn of cervical and thoracic segments than in lumbosacral segments. Using radioimmunoassay this gradient increase was quantitativ...
Kuczyński M, Słonka K.Stability of quiet upright stance was investigated in 25 children with cerebral palsy at the beginning and the end of a 3-month period of therapy involving 20 min microprocessor-controlled saddle riding, performed twice a week. The traditional parameters of postural sway based on the centre-of-pressure analysis (range, standard deviation, mean speed and mean radius) dropped significantly over time confirming advantageous influence of this treatment. As a complementary tool, an autoregressive modelling technique was used allowing us to establish after each single ride considerable decreases in ...
Blanco A, Moyano R, Vivo J, Flores-Acuña R, Molina A, Blanco C, Monterde JG.Purkinje cerebellar cells were studied in three Arabian horses aged between 6 and 8 months with clinical disorders in their movements, tremors and ataxia; the occurrence of apoptosis in this cell population was investigated by the (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labelling (TUNEL) method. Both optical and electron microscopical images showed a scant number of Purkinje cells, most of them with morphological features of apoptosis such as condensation of the nucleus and cytoplasm as well as segregation and fragmentation of the nucleus into apoptotic bodies. The TUNEL te...
Roberts VL, McKane SA, Williams A, Knottenbelt DC.REASONS FOR DESIGNING AND REPORTING TECHNIQUE: Idiopathic headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal lo...
Eydal M, Bambir SH, Sigurdarson S, Gunnarsson E, Svansson V, Fridriksson S, Benediktsson ET, Sigurdardóttir ÓG.Opportunistic infections with the free living nematode Halicephalobus gingivalis are infrequently reported in horses but the cases are widespread geographically. The nematodes are believed to penetrate wounds and subsequently reproduce within the host tissues. This paper reports two cases of a fatal disease in stallions of the Icelandic breed in Iceland. Case 1: a stallion, which sustained injuries to the mouth after an accident, developed severe neurological signs and had to be euthanatized. Histological examination revealed mild inflammation and malacia in the cerebellum associated with the ...
Boucher S, Arribarat G, Cartiaux B, Lallemand EA, Péran P, Deviers A, Mogicato G.Tractography, a noninvasive technique tracing brain pathways from diffusion tensor magnetic resonance imaging (DTI) data, is increasingly being used for brain investigation of domestic mammals. In the equine species, such a technique could be useful to improve our knowledge about structural connectivity or to assess structural changes of white matter tracts potentially associated with neurodegenerative diseases. The goals of the present study were to establish the feasibility of DTI tractography in the equine brain and to provide a morphologic description of the most representative tracts in t...
Guedes A.There has been great progress in the understanding of basic neurobiologic mechanisms of pain, but this body of knowledge has not yet translated into new and improved analgesics. Progress has been made regarding pain assessment in horses, but more work is needed until sensitive and accurate pain assessment tools are available for use in clinical practice. This review summarizes and updates the knowledge concerning the cornerstones of pain medicine (understand, assess, prevent, and treat). It highlights the importance of understanding pain mechanisms and expressions to enable a rational approach...
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...
Nollet H, Deprez P, van Ham L, Dewulf J, Decleir A, Vanderstraeten G.Cervical spinal cord dysfunction 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. Objective: 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 neurophysi...
Pálsdóttir AM, Gudmundsson M, Grahn P.People with neurological disorders suffer from poor mobility, poor balance, fatigue, isolation and monotonous everyday activities. Studies show that equine-assisted interventions can improve their mobility and balance, but could these kinds of interventions also increase participants' activity repertoire and self-assessed health, and reduce their fatigue? The study was conducted as a prospective, controlled study with three cohorts followed for one year: intervention group ( = 14), control group Passive ( = 29), and control group Active ( = 147). Participants in the study were affected by neur...
Bae SE, Corcoran BM, Watson ED.Little is known about neurogenic regulation of uterine contractility in mares. The present study investigated the distribution of adrenergic and peptidergic nerves in the mare uterus. Samples from the uterine horn, body and cervix were collected from 18 cyclic mares for immunohistochemistry. The uterus was well supplied with adrenergic nerves. A large number of tyrosine hydroxylase- and dopamine beta-hydroxylase-immunoreactive nerve bundles and fibres were present in the myometrium and endometrium in all regions of the uterus and cervix. These adrenergic nerve bundles and fibres travelled para...
Zenker W, Snobl D, Boetschi R.The dependence of the inner organisation and innervation of a skeletal muscle on its size was studied at the level of single muscle fiber architecture and motor endplate topography in muscles of different size, all of them lacking a tendinous scaffolding. The muscles evaluated in this study were: Mm. sternomastoideus, gracilis and latissimus dorsi of the rat and the M. sternocephalicus of the horse. In these muscles a subdivision into two or more 'innervation-compartments' becomes obvious in fascicles reaching a certain length. This provides the possibility of an almost synchronous activation ...
Capucchio MT, Márquez M, Pregel P, Foradada L, Bravo M, Mattutino G, Torre C, Schiffer D, Catalano D, Valenza F, Guarda F, Pumarola M.Many age-related changes are described in the nervous system of different species, but detailed studies of brain lesions in ageing horses are lacking. The aim of the present study was to systematically characterize lesions in the brains of 60 horses aged from 7 to 23 years. No gross changes were present in any brain. Microscopically, spongiform changes, lipofuscin storage, corpora amylacea, gliosis and satellitosis were common, together with axonal and neuronal swellings. The most important findings were the presence of pseudocalcium-calcium (pCa-Ca) deposits and arterial wall degeneration. Sc...
Beech J.Data were collected from 37 horses with a neurologic disability and compared to a group of 34 normal horses. Affected horses had neuroaxonal dystrophy, gliosis, vacuoles, and sometimes pigment localized to the accessory cuneate nuclei with minimal or no changes in the spinal cord and no changes in the proximal peripheral nerves. The focal nature of the change and usual absence of significant light microscopic spinal cord or peripheral nerve changes are different than previously described equine neuropathologic conditions.
Wheeler SJ, Plummer JM.Transverse sections of the lateral palmar nerve from a group of horses free from neuromuscular disease were assessed quantitatively, with emphasis on differences in the fibre population related to age. Morphometric analysis of the population of myelinated and unmyelinated fibres was performed. Changes were identified, there being a loss of larger myelinated fibres in older horses. The relationship of myelin thickness to axon diameter and the unmyelinated fibre population did not alter with age. The lateral palmar nerve is suitable for biopsy and electrophysiological study in the horse, but age...
Pountney DL, Fundel SM, Faller P, Birchler NE, Hunziker P, Vasák M.Human neuronal growth inhibitory factor (GIF) impairs the survival of cultured neurons and is deficient in the brains of Alzheimer's disease victims. We have isolated and sequenced analogous proteins from bovine and equine brain. By comparing their primary structures with those of human, mouse and rat GIFs, a consensus GIF sequence was obtained. Although this exhibits ca. 65% similarity with primary structures of mammalian metallothioneins (MTs), some significant differences are expected in the content of helix and turn secondary structures. In contrast to MTs, which usually bind 7 Zn(II) ions...
Purohit RC, Mysinger PW, Redding RW.A continuous series of electroencephalograms (EEG) was obtained from each of 6 mature horses which had been given xylazine and ketamine hydrochloride IV. Electrocardiograms and respiratory rates were also obtained. The EEG of the unsedated standing adult horse displayed a dominant fast activity in the range of 25-35 Hz, 5-30 microV superimposed over slower 1-4 Hz, 10-50 microV activity with occasional 10-14 Hz, 10-40 microV spindle-type activity. The xylazine-sedated horse displayed hypersynchronous EEG patterns, with the dominant activity being 1-3 Hz, 10-70 microV with overlying mixed freque...
