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.
Journée SL, Journée HL, Berends HI, Reed SM, Bergmann W, de Bruijn CM, Delesalle CJG.So far, only transcranial motor evoked potentials (MEP) of the extensor carpi radialis and tibialis cranialis have been documented for diagnostic evaluation in horses. These allow for differentiating whether lesions are located in either the thoraco-lumbar region or in the cervical myelum and/or brain. Transcranial trapezius MEPs further enable to distinguish between spinal and supraspinal located lesions. No normative data are available. It is unclear whether transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS) are interchangeable modalities. Unassigned: To pr...
de Melo UP, Ferreira C.Tetanus is a distressing and often fatal disease caused by exotoxins released by the bacterium . is a commensal of the gastrointestinal tract of humans and domestic animals, and its spores are highly resistant to environmental changes, acid, and alkali and may persist in the soil for many years. The disease is characterized by generalized muscular rigidity and spasms, hyperesthesia, convulsions, respiratory arrest, and death. Horses are the most susceptible domestic animals. Treatment is typically directed towards elimination of the source of the toxin, neutralization of any unbound toxin, es...
Walendy L, Goehring LS, Zablotski Y, Weyh T, Matiasek K, May A.Transcranial magnetic stimulation (TMS) has been successfully used in horses to evaluate function and integrity of descending motor pathways in patients affected by neurological gait abnormalities. In preceding studies, lengthening latency times (LT) of cranially evoked limb muscle potentials have been considered a reliable diagnostic parameter. Standardized settings use device output signal intensities of 100%. The aim of this study was to determine the effect of submaximal stimulation intensities (SI) and to determine the minimum coil output necessary to evoke motor unit potentials. As an ad...
Rojas-Núñez I, Gomez AM, Selland EK, Oduol T, Wolf S, Palmer S, Mohammed HO.Neurofilaments heavy chain proteins (pNF-H) have been identified as useful serum biomarkers for humans and animals with neurologic conditions, some of which can lead to poor performance, and athletic injuries. However, there are no published reports that describe a reference range for serum pNF-H levels in healthy racehorses. This cross-sectional study was carried out to determine the serum concentration of pNF-H in 1,349 samples collected from 1,291 clinically healthy standardbred (SB) racehorses. Data on age, time of sampling (pre-race or post-race), and finishing position during a race were...
Mühlemann S, Leandri M, Risberg ÅI, Spadavecchia C.The nociceptive withdrawal reflex (NWR) is used to investigate nociception in horses. The NWR threshold is a classical model endpoint. The aims of this study were to determine NWR tolerance and to compare threshold and tolerance reflexes in horses. In 12 horses, the NWR was evoked through electrical stimulation of the digital nerve and recorded via electromyography from the deltoid. Behavioral reactions were scored from 0 to 5 (tolerance). First, the individual NWR threshold was defined, then stimulation intensity was increased to tolerance. The median NWR threshold was 7.0 mA, whereas NWR tol...
Palumbo MIP, Resende LAL, Olivo G, de Oliveira-Filho JP, Borges AS.The visual evoked potential (VEP) has many applications in veterinary neurology, but the test is not routinely used in a clinical setting. The aim of this study was to describe a reliable method for recording flash visual evoked potentials (F-VEPs) in nonsedated horses. F-VEPs were recorded from both eyes in 20 healthy and calm, adult horses. Recordings were accomplished without sedation, anaesthesia, or the use of mydriatic drugs. The mean and standard deviation of the latency of the most evident positive peak was 52.76±2.37 ms (P53). The mean latencies of the preceding and following negativ...
Savage VL, Christley R, Pinchbeck G, Morrison LJ, Hodgkinson J, Peachey LE.Trypanosomosis is a major cause of morbidity and mortality in working equids in The Gambia. Recently, a progressive, severe neurological syndrome characterised by a diffuse lymphoplasmacytic meningoencephalitis has been identified and associated with Trypanosoma brucei infection of the central nervous system. The pathogenesis of cerebral trypanosomosis is unclear and the clinical syndrome not well described. This observational cross-sectional study aimed to identify host and parasite related risk factors associated with the development of cerebral trypanosomosis and to describe the neurologica...
Graïc JM, Peruffo A, Corain L, Finos L, Grisan E, Cozzi B.Cetartiodactyls include terrestrial and marine species, all generally endowed with a comparatively lateral position of their eyes and a relatively limited binocular field of vision. To this day, our understanding of the visual system in mammals beyond the few studied animal models remains limited. In the present study, we examined the primary visual cortex of Cetartiodactyls that live on land (sheep, Père David deer, giraffe); in the sea (bottlenose dolphin, Risso's dolphin, long-finned pilot whale, Cuvier's beaked whale, sperm whale and fin whale); or in an amphibious environment (hippopotam...
Milner PI, Dimmock O, Barnes K.Neurovascular variation may be relevant when performing surgical techniques to the proximal plantar metatarsal region. Objective: To document variations in the neurovascular anatomy of the proximal plantar metatarsal region and study the relationship of the neurovascular components to each other and other structures located in this area. Methods: Descriptive anatomical study. Methods: Paired cadaver hind limbs from 15 horses were dissected from the distal tibia to the metatarsophalangeal joint. Deep branch of the lateral plantar nerve (DBLPN) length, location of its origin from the lateral pla...
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...
Yang VY, Eaton JS, Harmelink K, Hetzel SJ, Sanchez A, Lund JR, Smith LJ.Injection techniques for retrobulbar anaesthesia are published in horses, but neither safety nor anaesthetic efficacy and duration have been evaluated objectively in vivo. Objective: To characterise the safety and efficacy of one published technique for retrobulbar anaesthesia. Methods: Randomised, controlled descriptive experiment. Methods: Unilateral retrobulbar injection with 10 mL lidocaine (2%) was performed in eight sedated adult mares. Contralateral eyes served as untreated controls. Neurophthalmic parameters, intraocular pressure (IOP), and corneal and periocular sensation were measur...
Animals must attend to a diverse array of stimuli in their environments. The emotional valence and salience of a stimulus can affect how this information is processed in the brain. Many species preferentially attend to negatively valent stimuli using the sensory organs on the left side of their body and hence the right hemisphere of their brain. Here, we investigated the lateralisation of visual attention to the rapid appearance of a stimulus (an inflated balloon) designed to induce an avoidance reaction and a negatively valent emotional state in 77 Italian saddle horses. Horses' eyes are late...
Schulze N, Ehrle A, Beckmann I, Lischer C.To report arthroscopic osteochondral fragment removal from the equine cervical spine articular process joints (APJs) including long-term follow-up. Methods: Case series. Methods: Three Warmblood horses with forelimb lameness and/or reduced range of motion of the cervical spine with osteochondral fragments between the cervical vertebrae C5 /C6 or C6 /C7 . Methods: Arthroscopy of the APJs of C5 /C6 and C6 /C7 was performed under general anesthesia. Following endoscopic evaluation of the joints, osteochondral fragments were removed using a rongeur. Results: All horses recovered from anesthesia wi...
Reed RA, Epstein KL, Bramski JH, Diehl KA, Ryan CA.To determine the effect of xylazine on intracranial pressure (ICP) in standing compared to isoflurane-anesthetized horses. Methods: Prospective, crossover study design. Methods: University Teaching Hospital. Methods: Six adult horses donated to the University. Horses were determined to be healthy via physical examination, complete blood count, and neurological evaluation. Methods: Horses were anesthetized, maintained on isoflurane in oxygen in left lateral recumbency, and ventilated to normocapnia. Horses were instrumented for intraparenchymal measurement of ICP, invasive blood pressure, pulse...
Heun F, Böing L, Theunert J, Gasse H.This basically anatomical study focuses on two items; firstly, the establishment of a system for the cartographic subdivision of the neopallium; secondly, the topographical correlation of extracranial landmarks and intracranial sites on the neopallium. Methods: The surface of the neopallium was subdivided into 15 sectors with reference to a newly introduced pattern of Primary Sulci. The topographical link between extracranial landmarks and certain intracranial sites (i.e. neopallium sectors) was elaborated by using a simple stereotactic device and a computer-assisted measurement device. Measur...
de Toledo A, Nomoto K, Hirano E, Tohda C.Human placental extract and animal-derived placental extracts from pigs and horses host a wide range of biological activities. Several placental products are used as medicines, cosmetics, and healthcare substances worldwide. However, the use of placental extracts for neuronal functioning is currently not established because the number of relevant studies is limited. A few previous reports suggested the neuroprotective effect and dendrite genesis effect of placental extract. However, no studies have reported on neurogenesis in placental extracts. Therefore, we aimed to investigate the effects o...
Edwards LA, Donnelly CG, Reed SM, Valberg S, Chigerwe M, Johnson AL, Finno CJ.Currently, there is little information regarding the concentrations of phosphorylated neurofilament heavy protein (pNfH) in the serum and cerebrospinal fluid (CSF) of horses with neurodegenerative diseases. Specifically, pNfH concentrations have not yet been evaluated in horses with equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM). Objective: To determine pNfH concentrations using a commercial enzyme-linked immunosorbent assay (ELISA) in serum and CSF from control horses and horses with eNAD/EDM, cervical vertebral compressive myelopathy (CVCM) and Shivers. Metho...
Bramski JH, Reed RA, Diehl KA, Epstein KL, Ryan CA.To determine whether an association exists between direct intracranial pressure (ICP) measurement and ultrasonographic measurement of optic nerve sheath diameter (ONSD) in anesthetized and standing horses. Methods: Cross-sectional study performed on a convenience sample of healthy adult horses. Methods: University teaching hospital. Methods: Eight adult horses donated to the University. Enrolled horses were free of abnormalities on physical examination, CBC, neurological evaluation, and ophthalmological examination. Results: Horses were anesthetized in lateral recumbency for placement of an IC...
Lee H, Hwang H, Ro Y, Kim JH, Lee K, Choi E, Bae Y, So B, Lee I.This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals. The occurrence of neurological diseases increased rapidly in the summer and 47 out of 50 horses were referred after the end of July. The incidence of neurological diseases started from the southern part of Korea in July and proceeded northward in August and September. Althoug...
Derham AM, Schumacher J, O' Leary JM, Kelly G, Hahn CN.Impinging/overriding dorsal spinous processes (DSPs) of the thoracolumbar vertebrae are a common cause of poor performance in horses. In the last five decades, numerous surgical treatments have been reported on, from transverse transection of the affected DSPs, and endoscopic resection of the affected DSPs, to transection of the interspinous ligament. Until recently, cosmetic outcomes have been reported as good to excellent in studies. However, a previously unreported complication of neurogenic atrophy of the contralateral epaxial muscle following desmotomy of the interspinous ligament has bee...
Zhu X, Suarez-Jimenez B, Zilcha-Mano S, Lazarov A, Arnon S, Lowell AL, Bergman M, Ryba M, Hamilton AJ, Hamilton JF, Turner JB, Markowitz JC....While effective treatments for posttraumatic stress disorder (PTSD) exist, many individuals, including military personnel and veterans fail to respond to them. Equine-assisted therapy (EAT), a novel PTSD treatment, may complement existing PTSD interventions. This study employs longitudinal neuro-imaging, including structural magnetic resonance imaging (sMRI), resting state-fMRI (rs-fMRI), and diffusion tensor imaging (DTI), to determine mechanisms and predictors of EAT outcomes for PTSD. Nineteen veterans with PTSD completed eight weekly group sessions of EAT undergoing multimodal MRI assessme...
Bernardino PN, Smith WA, Conrad PA, Packham AE, Tamez-Trevino E, Barnum S, Pusterla N.An ante-mortem diagnosis of equine protozoal myeloencephalitis (EPM) is presently based on clinical presentation, immunodiagnostics performed on serum and cerebrospinal fluid (CSF), and ruling out other neurological disorders. Molecular techniques introduce a novel and promising approach for the detection of protozoal agents in CSF. Hypothesizing that real-time PCR (rtPCR) can be a useful complement to EPM diagnostics, 210 CSF samples from horses suspected of neurological disease with EPM included as a differential diagnosis were tested using rtPCR to detect Sarcocystis neurona DNA and immunod...
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...
Škerlová J, Ismail A, Lindström H, Sjödin B, Mannervik B, Stenmark P.Organotin compounds are highly toxic environmental pollutants with neurotoxic and endocrine-disrupting effects. They are potent inhibitors of glutathione transferases (GSTs), thus impeding their detoxication and antioxidant functions. Several GSTs, including equine GST A3-3 (EcaGST A3-3), exhibit steroid double-bond isomerase activity and are involved in the biosynthesis of testosterone and progesterone. We have performed enzyme kinetics analyses of the inhibition of EcaGST A3-3 by organotin compounds. We have also solved crystal structures of EcaGST A3-3 in complexes with glutathione, and wit...
Fortin JS, Benskey MJ, Lookingland KJ, Patterson JS, Howey EB, Goudreau JL, Schott HC.Pituitary pars intermedia dysfunction (PPID) develops slowly in aged horses as degeneration of hypothalamic dopaminergic neurons leads to proliferation of pars intermedia (PI) melanotropes through hyperplasia and adenoma formation. Dopamine (DA) concentrations and tyrosine hydroxylase (TH) immunoreactivity are markedly reduced in PI tissue of PPID-affected equids and treatment with the DA receptor agonist pergolide results in notable clinical improvement. Thus, we hypothesized that pergolide treatment of PPID-affected horses would result in greater DA and TH levels in PI tissue collected from ...
Journée SL, Journée HL, Berends HI, Reed SM, de Bruijn CM, Delesalle CJG.Transcranial electrical (TES) and magnetic stimulation (TMS) are both used for assessment of the motor function of the spinal cord in horses. Muscular motor evoked potentials (mMEP) were compared intra-individually for both techniques in five healthy horses. mMEPs were measured twice at increasing stimulation intensity steps over the extensor carpi radialis (ECR), tibialis cranialis (TC), and caninus muscles. Significance was set at < 0.05. To support the hypothesis that both techniques induce extracranially elicited mMEPs, literature was also reviewed. Results: Both techniques show the pr...
Braza ME, Girotto JA.A 4-year-old female with prior cranial vault remodeling for nonsyndromic bilateral coronal craniosynostosis sustained a severe traumatic brain injury with open skull fractures from a horse kick. Her post-traumatic course was complicated by persistently elevated intracranial pressure despite neurosurgical decompressions, maximum medical therapy, and trial of multiple pressure monitoring devices. She eventually had improvement in her intracranial pressures and made a full neurologic recovery. This case highlights the potential severity of horse kick injuries, the possible etiology of persistent ...
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...
Aleman M, Berryhill E, Woolard K, Easton-Jones CA, Kozikowski-Nicholas T, Dyson S, Kilcoyne I.Sidewinder gait in horses is poorly understood and characterized by walking with the trunk and pelvic limbs drifting to 1 side. Objective: To report causes, clinical and diagnostic features. Methods: Horses examined at 2 institutions. Methods: Retrospective study (2000-2019). Cases with sidewinder gait, neurological and orthopedic examination, and diagnostic work up or postmortem evaluation were included. Descriptive statistics were performed. Results: Twenty-four horses (mean age 18.9 years) of various breeds and both sexes were included. Onset was acute (N = 10), subacute (N = 6), and insi...
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...
Wendell LC, Potter NS, Roth JL, Salloway SP, Thompson BB.Eastern Equine Encephalitis (EEE) virus is an arbovirus that mostly causes asymptomatic infection in humans; however, some people can develop a neuroinvasive infection associated with a high mortality. Methods: We present a case of a patient with severe neuroinvasive EEE. Results: A 21-year-old man initially presented with headache, fever, and vomiting and was found to have a neutrophilic pleocytosis in his cerebrospinal fluid. He eventually was diagnosed with EEE, treated with high-dose methylprednisolone and intravenous immunoglobulin. His course in the NeuroIntensive Care Unit was complicat...
Hanson RR.Complications of wounds and cosmetic surgery can be accurately managed with a combination of timely surgical and medical intervention to ensure the best possible outcome. The lack of soft tissue protection and a large quantity of susceptible synovial, tendon, ligament, and neurovascular structures make early and meticulous evaluation of limb wounds critical. Skin grafting is usually used following a period of open wound management and after healthy granulation tissue formation. Penetrating wounds of the abdomen or thorax have a guarded prognosis resulting from the ensuing potential for infecti...
Cozzi B, Povinelli M, Ballarin C, Granato A.The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in o...
Pearson GT.The architecture and neurochemistry of the enteric nervous system was studied by use of whole-mount preparations obtained by microdissection of the horse jejunum. A myenteric plexus and two plexuses within the submucosa were identified. The external submucosal plexus lying in the outermost region of the submucosa had both neural and vascular connections with the inner submucosal plexus situated closer to the mucosa. Counts of neurones stained for NADH-diaphorase demonstrated the wide variation in size, shape and neurone content of individual ganglia in both the external and internal submucosal...
Cummings JF, de Lahunta A, George C, Fuhrer L, Valentine BA, Cooper BJ, Summers BA, Huxtable CR, Mohammed HO.A spontaneous motor neuron disease or neuronopathy was identified in 10 horses from the northeastern United States. Signs of generalized weakness, muscle fasciculations, muscle atrophy and weight loss progressed over 1 to several months in young and old horses of various breeds. Pathologic studies revealed that degeneration and loss of motor neurons in the spinal cord and brain stem resulted in axonal degeneration in the ventral roots and peripheral and cranial nerves and denervation atrophy of skeletal muscle. Many spinal neurons were swollen, chromatolytic and contained neurofilamentous accu...
Knopp U, Christmann F, Reusche E, Sepehrnia A.Numerous types of materials have been evaluated over the past decades in the quest for the ideal dural replacement, but no product fully meets all the applicable criteria. This paper presents the long-term results of an animal trial of a collagen biomatrix (TISSUDURA, Baxter AG, Vienna/Austria) for the repair and regeneration of dural defects. This product provides a matrix with a special layer structure and consists of pure naturally cross-linked collagen of equine origin. The comparable material is Tutoplast Dura, a human cadaveric-derived dural graft preserved in a multiple stage chemical p...
Olivares R, Michalland S, Aboitiz F.A cross-species morphometric study of the corpus callosum was performed in the rat, rabbit, cat, dog, horse, cow and human. Across species, the results indicate a strong, although less than linear, dependency of callosal size on brain weight. This relation tends to lose significance within species. This is consistent with other morphometric studies indicating a tendency to decrease the correlations between morphometric variables in within-species analyses as compared to between-species analyses. There are species differences in the relative size of some callosal segments particularly in the po...
Aleman M, Gray LC, Williams DC, Holliday TA, Madigan JE, LeCouteur RA, Magdesian KG.Epilepsy is relatively uncommon in horses compared with other species and limited information is available. Objective: The objectives of the study were to describe the age of onset, clinical signs, clinicopathologic data, electroeticephalographic findings, treatment, and outcome, including long-term prognosis in Arabian foals with idiopathic epilepsy. Methods: Twenty-two foals were included in the study. Methods: Medical records from 1985 to 2005 were reviewed. Results: The age of onset of affected foals ranged from 2 days to 6 months. Seizures were characterized by generalized tonic and cloni...
Ballarin C, Povinelli M, Granato A, Panin M, Corain L, Peruffo A, Cozzi B.The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ)...
Roberts K, Hemmings AJ, Moore-Colyer M, Parker MO, McBride SD.A relationship between dopamine and temperament has previously been described in human cases of dopaminergic dysfunction. Adjustment in temperament prior to disease manifestation can enable the early identification of individuals at risk of such conditions, and scope exists to extend this application of temperament alterations to cases of dopaminergic dysfunction in horses. A multivariate and mixed-methods approach utilising a questionnaire along with two inferred measurements of dopamine activity (Spontaneous Blink Rate [SBR] and behavioral initiation rate [BIR]) were recorded from direct obs...
Sankey C, Henry S, Clouard C, Richard-Yris MA, Hausberger M.The aim of this study was to investigate the impact of training experience on young horses (Equus caballus)' lateralized responses to an approaching human. The results show that the one year old untrained horses display asymmetrical responses to an approaching human, with more negative reactions (escapes, threats) when approached from the left side, while approaches towards the right shoulder elicited more positive behaviors. On the contrary, two years old trained horses reacted equally positively to approaches and contact on both sides. Our findings support those of previous studies investiga...
Zhu X, Suarez-Jimenez B, Zilcha-Mano S, Lazarov A, Arnon S, Lowell AL, Bergman M, Ryba M, Hamilton AJ, Hamilton JF, Turner JB, Markowitz JC....While effective treatments for posttraumatic stress disorder (PTSD) exist, many individuals, including military personnel and veterans fail to respond to them. Equine-assisted therapy (EAT), a novel PTSD treatment, may complement existing PTSD interventions. This study employs longitudinal neuro-imaging, including structural magnetic resonance imaging (sMRI), resting state-fMRI (rs-fMRI), and diffusion tensor imaging (DTI), to determine mechanisms and predictors of EAT outcomes for PTSD. Nineteen veterans with PTSD completed eight weekly group sessions of EAT undergoing multimodal MRI assessme...
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...
Nollet H, Van Ham L, Deprez P, Vanderstraeten G.Transcranial magnetic stimulation is rapidly developing as a powerful, non-invasive tool for studying the descending motor tracts in humans. The applications of the test in animals are for the moment restricted to small animals. However, this non-invasive, sensitive and painless technique appears promising as a test of motor tract function in horses where the neurological examination is mainly restricted to clinical evaluation and some ancillary tests, such as radiography, cerebrospinal fluid analysis and electromyography. In this review, we want to discuss the history, basic principles, techn...
Williams DC, Aleman M, Tharp B, Fletcher DJ, Kass PH, Steffey EP, LeCouteur RA, Holliday TA.The administration of certain sedatives has been shown to promote sleep in humans. Related agents induce sleep-like behavior when administered to horses. Interpretation of electroencephalograms (EEGs) obtained from sedated horses should take into account background activity, presence of sleep-related EEG events, and the animal's behavior. Objective: Sedatives induce states of vigilance that are indistinguishable on EEGs from those that occur naturally. Methods: Six healthy horses. Methods: Digital EEG with video was recorded after administration of 1 of 4 sedatives (acepromazine, butorphanol, ...
Johnson CB, Taylor PM.We have investigated in eight ponies the effects of three different end-tidal concentrations of halothane, isoflurane and methoxyflurane on median (F50) and 95% spectral edge (F95) frequencies of the EEG and the second differential (DD) of the middle latency auditory evoked potential (MLAEP). The three concentrations of each agent were chosen to represent approximately the minimum alveolar concentration (MAC), 1.25 MAC and 1.5 MAC for each agent. During halothane anaesthesia, F95 decreased progressively as halothane concentration increased, from mean 13.9 (SD 2.6) at 0.8% to 11.9 (1.1) at 1.2%...
Sarkar DK, Smith GC, Fink G.We have investigated the effect of manipulating central catecholamines on the timing of puberty (as assessed by vaginal opening) in female rats and the surge of luteinizing hormone (LH) and gonadotropin releasing hormone (GnRH) induced by pregnant mare serum gonadotropin (PMSG) in immature female rats. Manipulation of the catecholamines was carried out with either 6-hydroxydopamine (6-OHDA) administered with or without either desipramine (DMI) or pargyline, or alpha-methyl-p-tyrosine (alpha-MPT). The neonatal administration of 6-OHDA delayed puberty, an effect which was potentiated by pretreat...
Chagnaud BP, Simmers J, Straka H.In guiding adaptive behavior, efference copy signals or corollary discharge are traditionally considered to serve as predictors of self-generated sensory inputs and by interfering with their central processing are able to counter unwanted consequences of an animal's own actions. Here, in a speculative reflection on this issue, we consider a different functional role for such intrinsic predictive signaling, namely in stabilizing gaze during locomotion where resultant changes in head orientation in space require online compensatory eye movements in order to prevent retinal image slip. The direct...
Carroll CL, Westbury HA.This research paper discusses the isolation of equine herpesvirus 1 (EHV1) from the brain of a horse experiencing paresis, demonstrating the connection between EHV1 infections and neurological disorders like ataxia, […]
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.
Rohrbach H, Korpivaara T, Schatzmann U, Spadavecchia C.To evaluate and compare the antinociceptive effects of the three alpha-2 agonists, detomidine, romifidine and xylazine at doses considered equipotent for sedation, using the nociceptive withdrawal reflex (NWR) and temporal summation model in standing horses. Methods: Prospective, blinded, randomized cross-over study. Methods: Ten healthy adult horses weighing 527-645 kg and aged 11-21 years old. Methods: Electrical stimulation was applied to the digital nerves to evoke NWR and temporal summation in the left thoracic limb and pelvic limb of each horse. Electromyographic reflex activity was reco...
Magee C, Foradori CD, Bruemmer JE, Arreguin-Arevalo JA, McCue PM, Handa RJ, Squires EL, Clay CM.The purpose of the present study was to evaluate the effects of kisspeptin (KiSS) on LH and FSH secretion in the seasonally estrous mare and to examine the distribution and connectivity of GnRH and KiSS neurons in the equine preoptic area (POA) and hypothalamus. The diestrous mare has a threshold serum gonadotropin response to iv rodent KiSS decapeptide (rKP-10) administration between 1.0 and 500 microg. Administration of 500 microg and 1.0 mg rKP-10 elicited peak, mean, and area under the curve LH and FSH responses indistinguishable to that of 25 microg GnRH iv, although a single iv injection...
Lacombe VA, Sogaro-Robinson C, Reed SM.The use of computer tomography (CT) and contrast-enhanced CT (CCT) to image the head is common. However, the validity of CT as a neurodiagnostic indicator of intracranial diseases in horses is unknown. Objective: To define the validity of CT and CCT in horses with suspected intracranial disorders. Methods: The validity of CT imaging was estimated by comparing clinical, clinicopathological and histopathological findings to CT findings in 15 horses presented for intracranial disorders, for which pre- and post contrast CT images and post mortem examination of the brain and skull were reviewed. Po...
Petter-Puchner AH, Froetscher W, Krametter-Froetscher R, Lorinson D, Redl H, van Griensven M.While fibrin sealant (FS) and equine collagen (EC) have been used as scaffold materials in experimental spinal cord injury (SCI), questions concerning neurocompatibility still remain. In this study, we assessed potential adverse effects, as well as functional and histological impact of FS and EC in subtotal hemisection of the thoracic spinal cord (SC) in rats. Methods: 124 male rats were randomly assigned to four main groups (n=31): Sham (SH), Lesion only (L), fibrin sealant (GFS) and equine collagen group (GEC). SH animals received laminectomy only; all other animals underwent subtotal latera...
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...
