The equine brain is a complex organ responsible for processing sensory information, regulating behavior, and controlling motor functions in horses. It plays a part in cognitive processes such as learning, memory, and decision-making. The equine brain is divided into several regions, each with distinct functions, including the cerebrum, cerebellum, and brainstem. Research in this area often focuses on understanding the neurological pathways and mechanisms that underlie equine behavior and performance. This topic encompasses studies that explore brain anatomy, neurophysiology, and the effects of various factors such as stress, training, and disease on brain function in horses. This page compiles peer-reviewed research studies and scholarly articles that investigate the structure, function, and health of the equine brain.
Reed SM.Trauma to the nervous system in horses may involve the brain, brainstem, spinal cord, or peripheral nerves. Trauma may occur to any part of the nervous system with or without a fracture.
Uzal FA, Doxey DL, Robles CA, Woodman MP, Milne EM."Mal seco" is a disease of unknown aetiology affecting horses in Argentina. It is similar to grass sickness, a primary dysautonomia of horses in Europe. A histopathological study of the brain stem nuclei of three horses with "mal seco" was performed. Changes were found that consisted of chromatolysis, cytoplasmic vacuoles, eosinophilic sphaeroids, and pyknotic and eccentric nuclei. These changes were most severe at the oculomotor, vestibular and abducent nuclei. The results provide further evidence to suggest that "mal seco" and grass sickness may be the same disease.
Newton-Clarke MJ, Divers TJ, Delahunta A, Mohammed HO.A study was conducted over a 12 month period to assess the specificity and sensitivity of the 'slap test', using endoscopic evaluation, in the detection of cervical spinal cord and caudal brainstem lesions in horses. Fifteen ataxic horses were subjected to the 'slap test' and subsequently examined post mortem. Twelve out of the 15 had histopathological lesions consistent with their clinical signs. Thirteen horses with no history of neurological dysfunction and no histopathological evidence of cervical spinal cord or brainstem disease were used as controls. The laryngeal adductory responses exh...
Andrews FM, Geiser DR, Sommardahl CS, Green EM, Provenza M.Total protein (TP), albumin, and IgG concentrations were measured in CSF from the atlanto-occipital (AO) and lumbosacral (LS) sites and in serum of 15 clinically normal neonatal foals < or = 10 days old (mean, 7.0 days). The albumin quotient (AQ; CSF albumin/serum albumin x 100) and IgG index ([CSF IgG/serum IgG] x [serum albumin/CSF albumin]), indicators of blood-brain barrier permeability and intrathecal IgG production, respectively, were then calculated. Mean +/- SD values obtained from the foals of this study were: serum albumin, 2,900 +/- 240 mg/dl; serum IgG, 1,325 +/- 686 mg/dl; AO CSF ...
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...
Kim DY, Hodgin EC, Lopez MK, Nasarre C.A large primary retroperitoneal sublumbar neoplasm in a horse, with disseminated neoplastic foci in the brain, lung, kidney and spleen is described. The diagnosis was based on light microscopical studies and positive immunostaining for neuron-specific enolase. Because of the location of the primary tumour mass, the aortico-sympathetic ganglion (organ of Zukerkandl) is proposed as the origin.
Lowry TF, Forster HV, Korducki MJ, Forster AL, Forster MA.To gain insight into central and peripheral contributions to changes in breathing during hypoxia, we compared effects on breathing of reducing inspired PO2 (hypoxic hypoxia) with reducing arterial O2 content (CaO2) through elevation of carboxy-hemoglobin (COHb) (CO hypoxia). Twelve awake ponies were studied during 1 h of breathing room air followed by 6 h when COHb was increased to 25% and CaO2 was decreased by 17%. When COHb was increased, arterial PCO2 (PaCO2) increased gradually to 1.3 Torr above (P < 0.05) control level between 30 and 45 min of CO exposure. Pulmonary ventilation (VE) de...
Zimmermann W, Dürrwald R, Ludwig H.Borna disease virus in naturally infected horses, a donkey and sheep was detected for the first time by amplification of viral RNA using PCR. In contrast to a control group of healthy horses, brain tissue was positive by this assay in all animals with neurological symptoms. The use of a second round of PCR with nested primers following Southern hybridization confirmed the specificity and increased the sensitivity of the test. Comparison with conventional methods recommends this technique for monitoring of BDV infections at a molecular level.
Melrose PA, Pickel C, Cheramie HS, Henk WG, Littlefield-Chabaud MA, French DD.Recent reports have indicated that analysis of changes in the staining characteristics of gonadotropin-releasing hormone (GnRH) neurons and characterization of morphological plasticity of the related structural framework may help to elucidate the physiological mechanisms involved in neuroendocrine control of mammalian reproduction. Whether comparative studies will facilitate this process or simply elucidate species-specific mechanisms is not yet clear. The present study was performed in order to begin analysis of GnRH neurons in a seasonally breeding species that exhibits an unusually long ovu...
Tyler CM, Davis RE, Begg AP, Hutchins DR, Hodgson DR.Case records of 450 horses with signs of neurological disease are reviewed. One hundred and nineteen horses with neurological disease due to trauma were examined, of which 60 were due to spinal cord trauma, 47 to brain or cranial nerve trauma and 12 to peripheral nerve trauma. Cervical vertebral fractures/trauma were the most common injury. Basisphenoid/basioccipital bone fractures were the most common form of cranial trauma and facial nerve paralysis the most common cranial nerve injury. Eighty-nine horses with neurological disease due to malformation were examined. Cervical vertebral malform...
Kamerling SG.The recognition and alleviation of animal pain is a growing veterinary and public concern. Pain can be of an acute or chronic nature with different behavioral manifestations. Physiologically, pain is a dynamic and complex phenomenon that produces changes in the central and autonomic nervous systems as well as in the endocrine system. Horses and other animals appear to possess an endogenous pain-suppressing system involving the brainstem and spinal cord. This system can modulate pain perception and the responses to it. The recently discovered endogenous opioid peptides (endorphins and enkephali...
Regodon S, Franco A, Lignereux Y, Redondo E.A technique is described for catheterisation of the ventricular recess within the olfactory bulb of the horse. Twelve adult horses were used. The olfactory recess is in the frontal region, 42 +/- 3 mm below the skin, on the line joining the supraorbital foramina, and approximately 18 +/- 2 mm from the midline. The approach is relatively easy under normal experimental conditions.
Freeman DE, Staller GS, Maxson AD, Sweeney CR.A mare with hemorrhage caused by guttural pouch mycosis was treated by insertion of a balloon-tipped catheter into the left internal carotid artery. During recovery from general anesthesia, the mare had profuse epistaxis, and was anesthetized again to determine the site of hemorrhage. The affected guttural pouch was opened to confirm that hemorrhage was from the left internal carotid artery. The mare was euthanatized, and, at necropsy, the balloon catheter was found in an aberrant branch that arose from the internal carotid artery and joined the basilar artery. The mycotic plaque was on the le...
Johnson PJ, Lin TL, Jennings DP.Cholesterinic granulomas, commonly found at necropsy in aged horses, may cause neurologic signs by obstructing the interventricular foramina, resulting in hydrocephalus. Diffuse cerebral disease in horses may not always result in rapid progression of clinical signs. Intermittency of neurologic signs may be associated with intermittent increases in CSF pressure.
Ludwig H, Furuya K, Bode L, Klein N, Dürrwald R, Lee DS.Borna disease viruses (BDV) isolated from more than 20 naturally infected horses, 2 sheep and a possible feline isolate were included in these studies. Most of these wild-type viruses were grown in rabbit cells. Specifically rabbit-adapted viruses establish persistent infection in immortalized cell lines of various animal species. Brain-, tissue culture-, and cell-free released viruses could all be neutralized with antibodies from naturally and experimentally infected animals (horse; hamster, rat, rabbit, mouse, and chicken), with highest titres in birds. Splenectomized rabbits, which were sub...
Stitz L, Bilzer T, Richt JA, Rott R.Borna disease represents a unique model of a virus-induced immunological disease of the brain. Naturally occurring in horses and sheep, the mechanisms of pathogenesis have been studied in experimental animals, namely in the rat. Many investigations have revealed that the infection of the natural hosts principally follows the same pathogenic pathways as observed in rats, leading to a severe encephalomyelitis. This affliction of the central nervous system results in severe neurological disorders that again, are fully comparable in laboratory animals to those in the natural and the different expe...
Masri MD, Alda JL, Dubey JP.Sarcocystis neurona-like schizonts were found in sections of brain and spinal cord of two ataxic horses from Brazil. The diagnosis was supported by staining with anti-Sarcocystis serum in an immunohistochemical test. One of the affected horses was born in Argentina and raised in Brazil, and the other horse was born and raised in Brazil.
Sikkes BP, Manohar M, Duren SE, Day J, Baker JP.Experiments were carried out on 8 healthy ponies to examine the effects of prolonged submaximal exercise on regional distribution of brain blood flow. Brain blood flow was ascertained by use of 15-microns-diameter radionuclide-labeled microspheres injected into the left ventricle. The reference blood was withdrawn from the thoracic aorta at a constant rate of 21.0 ml/min. Hemodynamic data were obtained with the ponies at rest (control), and at 5, 15, and 26 minutes of exercise performed at a speed setting of 13 mph on a treadmill with a fixed incline of 7%. Exercise lasted for 30 minutes and w...
Aminlari M, Vaseghi T.1. A new colorimetric method was used for determination of arginase in different tissues of some domestic animals. 2. In all species studied liver was the richest source of arginase. 3. Significant differences were observed in the specific activity of arginase in livers from different species. 4. In all species, besides liver, kidney and brain also contained significant levels of arginase. 5. In the dog, in addition to the three organs mentioned above, lung, heart, spleen and skeletal muscle showed some arginase activity. 6. In sheep and cattle significant arginase activity was observed in the...
Moore RM, Trims CM.Lumbosacral CSF pressure was measured in 6 horses via a catheter inserted through the lumbosacral space. Heart rate, facial artery pressure, central venous pressure, and CSF pressure were measured before IV injection of a saline solution control, for 15 minutes after saline solution injection, and for 60 minutes after the IV injection of 1.1 mg of xylazine/kg of body weight. Arterial pH and blood gases were analyzed before saline solution injection, 15 minutes after saline solution injection, and at 15, 30, and 60 minutes after xylazine injection. Constant craniocervical posture was maintained...
Gulevskiĭ AK, Grishchenko VI, Tereshchenko OS, Zagnoĭko VI, Akhremenko AK, Kucherenko SN.The effect of the fraction (1-10 kDa) obtained from the brain of cold-adapted animal (Yakut horse) on Ca2+ transport in sarcolemma vesicles of cardiomyocytes was investigated. It was shown that during insertion of Yakut horse brain fraction into incubation medium at the concentration from 10(-9) M to 3.10(-5) M at Ca2+ transport substrate concentration from 0.1 mM to 1.0 mM, the rate of Ca2+ passive penetration into vesicles slightly increased and at Ca2+ transport substrate concentration 3 mM, which is physiologic, a decrease of rate values was established for all concentrations of the fracti...
Mayhew IG, Washbourne JR.The Brainstem Auditory Evoked Potential (BAEP) is a recording of the electrical activity of the brainstem following an acoustic stimulation. Up to seven peaks may be identified within 10 ms, and are labelled I to VII. The first five of these peaks are of most clinical importance, and in normal horses, peaks I, III and V are always present at stimulus intensities of 70-100 dB. Repeated sampling of clinically normal subjects at different stimulus intensities has enabled mean latency values to be determined for the ipsilateral and contralateral peaks I, III and V, and also for the interpeak laten...
Green SL, Smith LL, Vernau W, Beacock SM.The records of 21 horses with rabies were reviewed. Results of fluorescent antibody testing for rabies antigen in brain tissue were positive in each case. According to the histories, 5 of the horses had been vaccinated for rabies between 4 to 24 months prior to the onset of the clinical signs. Bite wounds were not observed on any of the horses, and exposure to a suspected rabid animal was witnessed in only 5 cases. Clinical signs of disease at the time of initial examination included ataxia and paresis of the hindquarters (9/21, 43%), lameness (5/21, 24%), recumbency (3/21, 14%), pharyngeal pa...
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...
Fleming JT, Joshi JG.We previously showed that human brain ferritin (HBF) binds aluminum (Al) in vivo and in vitro and HBF isolated from Alzheimer's brain had more Al bound compared to aged matched controls (7). To further understand the role ferritin may play in Al neurotoxicity, we have studied in vitro the effect of Al on the function of human ferritin isolated from Alzheimer's (AD) and normal brain tissue, and compared the results with other mammalian ferritins. Al causes a concentration-dependent decrease in the initial rate of iron loading into apo-horse spleen and human brain ferritin and the rates were sim...
Dubey JP, Davis SW, Speer CA, Bowman DD, de Lahunta A, Granstrom DE, Topper MJ, Hamir AN, Cummings JF, Suter MM.Sarcocystis neuronan n. sp. is proposed for the apicomplexan taxon associated with myeloencephalitis in horses. Only asexual stages of this parasite presently are known, and they are found within neuronal cells and leukocytes of the brain and spinal cord. The parasite is located in the host cell cytoplasm, does not have a parasitophorous vacuole, and divides by endopolygeny. Schizonts are 5-35 microns x 5-20 microns and contain 4-40 merozoites arranged in a rosette around a prominent residual body. Merozoites are approximately 4 x 1 micron, have a central nucleus, and lack rhoptries. Schizonts...
Hunt RJ, Allen D, Mueller PO.Heterotopic polyodontia is typically associated with a sinus and a fistulous tract with a secreting membrane which extends to an ectopic tooth attached to the temporal bone. Recommendations for treatment include complete excision of the tract, the dental component, and the lining of the alveolar socket. Iatrogenic cerebral trauma was encountered during surgical extraction of an ectopic tooth. At post-mortem examination a second ectopic tooth was found compressing the right side of the cerebellum.
Kolb DS, Klein C.Congenital hydrocephalus has been reported for a number of horse breeds, and for Friesian horses this condition has been associated with a nonsense mutation of B3GALNT2. We report the first case of congenital hydrocephalus associated with the said mutation in a Belgian draft horse. Genetic testing and consideration of the testing results in breeding programs are warranted. Hydrocéphalie congénitale chez un cheval de trait Belge associée à une mutation non-sens de B3GALNT2. L’hydrocéphalie congénitale a été signalée pour plusieurs races de chevaux et, pour les chevaux Frisons, cette ...
Kelly DF, Watson WJ.An aged Connemara mare had a neurological illness lasting 3 weeks and characterised by episodes of dullness, head-pressing, staggering gait and hyperexcitability. The signs recurred at intervals of 3 to 4 days, with intervening periods of apparent normality. Post-mortem examination revealed an epidermoid cyst on the dorsal surface of the occipital lobe of the left cerebral hemisphere. The cyst was lined by stratified squamous epithelium and contained desquamated keratinised material and blood. The lesion is considered to be a congenital malformation which enlarges and produces space-occupying ...
Bunton TE.Developmental defects are rarely reported in the horse. Severe craniofacial and central nervous system defects in an equine foetus are described and their possible causation and pathogenesis are suggested.
Dubey JP, Miller S.A 10-year-old pony died 5 days after the onset of a nervous disorder. Necropsy revealed a yellowish area of discoloration (1.5 by 1 cm) in the medulla oblongata. Microscopically, necrosis and nonsuppurative myeloencephalitis were found in the medulla oblongata. Immature and mature meronts (25 by 10 microns) were seen in neural tissue and in capillaries of the brain stem. Organisms were similar structurally to those seen in equine protozoal myeloencephalitis of horses.
Huxtable CR, de Lahunta A, Summers BA, Divers T.Marginal siderosis is recognized in humans as an uncommon clinicopathologic entity characterized by degeneration of neural tissue at the surface of the brain and spinal cord, in association with the accumulation of hemosiderin, and resulting from chronic subarachnoid hemorrhage. The sources of hemorrhage are various and include neoplasms, malformations, cysts, and vasculopathy. Marginal siderosis of the spinal cord due to a myxopapillary ependymoma was diagnosed in a 19-year-old Dutch Warm Blood horse with clinical signs of myelopathy. There is only one previous report of marginal siderosis in...
Hobbs KJ, Porter E, Wait C, Dark M, MacKay RJ.Magnetic resonance imaging is increasingly available for evaluation of horses with suspected pituitary adenomas; however, published studies describing the MRI features of normal equine pituitary glands are currently lacking. This retrospective, descriptive, anatomic study describes the MRI appearance and size of presumed normal equine pituitary glands and assesses potential correlations between pituitary size, brain size, and patient weight. These findings serve as a reference for MRI evaluation of the equine pituitary gland. Inclusion criteria consisted of adult horses (2-15 years old), over ...
Carrigan MJ, Higgins RJ, Carlson GP, Naydan DK.A 17-year-old Arabian gelding with progressive neurologic signs had a velvety, reddish brain tumor protruding from the ventral midline caudal to the optic chiasma. Histologically, the tumor had a papillary formation with a single layer of elongate cells radially oriented around a central fibrovascular core. Intracytoplasmic globular inclusions were positive for glial fibrillary acidic protein and weakly positive for vimentin. Ultrastructurally, these inclusions were comprised of whorling intermediate filaments. Neoplastic cells also had cytoplasmic interdigitations and numerous zona adherens a...
Dollahite JW, Younger RL, Crookshank HR, Jones LP, Petersen HD.Lead acetate was fed to 4 groups of 2 horses each to study chronic lead intoxication. A 5th group of 3 horses was maintained as controls. The leas was fed in capsules, with the minimum dosage of 6.25 mg/kg/day of lead as lead acetate (group I). The dose was increased from group I through group IV in an approximate geometric series, with each group being given about 125% of the dose given the previous group. These doses were given for 105 days, a period designated as phase 1. Since clinical signs were not observed after 105 days, the doses were increased and fed for an additional 190 days (days...
Raphel CF.Three horses with brain abscesses had different clinical manifestations: 1 had a protracted clinical course whereas 2 had a short clinical course. Clinical signs in 2 horses (1 acute case, 1 chronic case) included unilateral loss of vision, head tilt, circling, abnormal mental status, and ataxia. The 3rd horse had bilateral loss of vision, altered mental status, and apparent deafness. Results of cerebrospinal fluid analysis were inconsistent. The horse with the protracted clinical course had paradoxic central vestibular disease.
Allnoch L, Peters M, Wiemer F, Wohlsein P.Severe bilateral mydriasis and bilaterally decreased vision were observed in a 23-year-old crossbred warmblood gelding with a history of pituitary pars intermedia dysfunction. Ten years after the onset of clinical signs, it was killed humanely because of worsening of clinical signs and loss of therapeutic responsiveness. Postmortem examination of the head was performed to confirm the suspected pituitary neoplasm and to investigate secondary oculomotor lesions. Pathomorphologic examination revealed an expansile space-occupying pituitary adenoma and degenerative changes in the preganglionic ocul...
Tokunaga S, Fujiki M, Yabuki A, Misumi K.Cartilage-derived retinoic acid-sensitive protein (CD-RAP)/melanoma inhibitory activity (MIA), which appears abundantly in hypertrophic cartilage at the stage of endochondral ossification, is also detected in cerebrospinal fluid (CSF) following spinal cord injury. In this study, the localization of the CD-RAP/MIA molecule in normal tissues of the spine and brain obtained from mice, rats, dogs, cattle and horses was examined using immunohistochemistry with a specific antibody. The positive signals of CD-RAP/MIA were found at nerve cells in the spinal cords of all species and were especially str...
Saliou G, d'Ablon X, Théaudin M, Saliou T, Bourassi S.Performing a brain computerized tomography scan (CT scan) on a foal requires specific equipment and anesthesia for large animals. However, the information obtained may demonstrate lesions responsible for the neurological deficits. Especially, CT scan findings may help to understand a mechanism of cerebral ischemia. Indeed, categories of cerebral ischemia are divided in three types: territorial infarctions (downstream of the territory of an artery), watershed infarctions (slow-flow at the junction of two arterial territories), and lacunar infarctions (small-vessel occlusions). Hypersensitivity ...
Harkness RA, McCreanor GM, Allsop J, Snow DH, Harris RC, Rossdale PO, Ousey JC.1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities ...
Olofsson KM, van de Velde N, Peletto S, Iulini B, Pratley L, Modabberzadeh B, Małek E, Grandi G.Halicephalobus gingivalis is a nematode with zoonotic potential which can cause fatal opportunistic infections in various mammals. The parasite has never been diagnosed in Sweden, in any species, prior to the presented case. Methods: An imported 21-year-old Icelandic mare developed severe neurological signs. The horse was eventually euthanized and submitted for post-mortem examination where severe lesions in the kidneys were noted. Histopathology revealed the presence of H. gingivalis in both kidneys and the brain. Phylogenetic analysis of the parasite determined it to belong to Lineage 1. Con...
Morlière P, Mazière JC, Patterson LK, Conte MA, Dupas JL, Ducroix JP, Filipe P, Santus R.Ferritin (Ft) impairment through (•)O2(-), H2O2, and (•)OH production occurs in the cases of ketoses, diabetes mellitus, acute intermittent porphyria and tyrosinemia. In addition to (•)Trp and TyrO(•) radical production, ferrous iron liberation and Ft synthesis stimulation, site-specific oxidation reactions are induced leading to toxic iron accumulation in organs with high Ft content, for example, liver and brain. To elucidate the potential pathways to Ft recovery, repair of oxidative damage to horse spleen apoferritin (apoFt) and Ft by quercetin (QH) or rutin (RH) was studied in the p...
Tunev SS, Ehrhart EJ, Jensen HE, Foreman JH, Richter RA, Messick JB.An 18-year-old Morgan mare was presented to the Veterinary Medical Teaching Hospital, University of Illinois, with a 10-day history of watery diarrhea, depression, and dysphagia. On admission, the animal was severely dehydrated, depressed, and unable to swallow and had no clinical signs of diarrhea. The respiratory and heart rate and body temperature were within normal limits. Following fluid therapy, the mare developed severe watery diarrhea and continued to be depressed, incoordinated, and dysphagic. The animal died on the fourth day after admission and was sent to the Laboratories of Veteri...
Mikami T, Tsuchihashi K, Kashiwagi M, Yachida Y, Daino T, Hashi K, Akino T, Gasa S.A sulfatide, O-fatty-acylated 3-sulfogalactosylceramide at C6-O on galactoside, was isolated from equine brain and the chemical structure was characterized by proton NMR and MS. The O-acylation site of the acylated sulfatide was determined by the down-field shift of protons attached to a carbon having an O-acyl group in the NMR spectrum and by analysis of a partially methylated derivative before and after acetalization of the intact sulfatide using GC-MS. The O-acyl chain length was determined by GLC, revealing that it exclusively had palmitoyl and stearoyl residues as the major fatty acids. T...
Melrose PA, Knigge KM.The present study describes the topography of immunoreactive (ir) oxytocin (OXY) and vasopressin (AVP) neurons in the forebrain of Equus caballus and the coexistence of ir proopiomelanocortin (POMC)-derived peptides in the same cells. These data are compared to those for other mammalian species and the possible significance of species variations is considered. As expected, magnocellular neurons of the equine hypothalamus, which contain ir OXY or AVP, have prominent discernible projections to the neurohypophysis. Further, as in other mammalian species, the field of ir OXY perikarya generally ex...
Reynolds BL, Stedham MA, Lawrence JM, Heltsley JR.A space-occupying intracranial mass was diagnosed in a horse. The clinical findings included blindness, circling to the right, apprehension, anorexia, weight loss, and leaning against the stall. On ophthalmoscopic examination, the most striking observation was complete bilateral devascularization of the retinas. The horse was euthanatized and necropsied. Necroscopy revealed the mass to occupy the olfactory and frontal areas of the left hemisphere of the brain and part of the left frontal sinus. Microscopically, the mass was an adenocarcinoma and probably arose from the lining epithelium of the...
Bae JH, Ahn K, Nam GH, Lee CE, Park KD, Lee HK, Cho BW, Kim HS.The horse BMAL1 gene encodes the brain and muscle Arnt-like protein 1, which is a key regulator of circadian rhythmic systems in most organs and cells. The first exon of the horse-specific BMAL1 gene is produced by an exonization event of LINE3 (CR1) and SINE (MIR) was detected by bioinformatic analysis. Alternative variants generated by cassette exon event in various horse tissues were also detected by RT-PCR amplification and sequencing. The cDNA sequences of the horse transcripts (BMAL1a, BMAL1b) contain additional 21 bp and 71 bp fragments relative to horse BMAL1. Quantitative real-time RT...
Manohar M, Goetz TE.To examine regional distribution of blood flow in the brain of horses at rest and during exercise. Methods: 9 clinically normal horses. Methods: Regional brain blood flow was measured using radionuclide-labeled 15-microns-diameter microspheres injected into the left ventricle, while reference blood samples were obtained from the aorta. Results: At rest, cerebral cortex and caudate nuclei received significantly higher blood flow, compared with cerebral white matter. A similar perfusion heterogeneity existed in the cerebellum. In the brain stem, a gradual tapering of blood flow from thalamus-hyp...
Draper ACE, Cahalan SD, Goodwin D, Perkins J, Piercy RJ.Equine recurrent laryngeal neuropathy (RLN) is a naturally occurring model of length-dependent axonopathy characterized by asymmetrical degeneration of recurrent laryngeal nerve axons (RLn). Distal RLn degeneration is marked, but it is unclear whether degeneration extends to include cell bodies (consistent with a neuronopathy). With examiners blinded to RLN severity, brainstem location, and side, we examined correlations between RLN severity (assessed using left distal RLn myelinated axon count) and histopathological features (including chromatolysis and glial responses) in the nucleus ambiguu...
Lippert-Gruner M, Svestkova O.The acute management of spasticity following ABI is challenging. Contractures can occur during the acute phases of illness. The joints most affected are the shoulders and the ankles. Methods: A case study of a 48-year-old female patient who received local chemoneurolytic anti-spasticity therapy following a severe subarachnoid haemorrhage for pes equines deformity is presented to illustrate the role of focal neurotoxin therapy. Methods: The increasing spasticity in her legs was observed and could not be effectively treated with oral anti-spasticity agents or intensive physiotherapy. As spastici...
Orr JA, Wagerle LC, Kiorpes AL, Shirer HW, Friesen BS.This study determined whether blood flow through the internal carotid artery (ICA) could be used to sample total cerebral blood flow in the pony. To answer this question we considered both the anatomic arrangement of the ICA in cadavers and the relative distribution of ICA blood flow to cerebral and extracerebral tissue using radioactive microspheres. Acrylic corrosion casts of the ICA indicated that this vessel traveled directly to the base of the brain, contributing to the formation of the circle of Willis, and did not send any significant branches to other tissues. Two vessels (internal eth...
Scrivani PV.Neuroimaging underwent a dramatic revolution during the past few decades due to the development of new technologies that produce exquisite images of patient morphology and function, new technologies that store and distribute information more efficiently, and research that has improved understanding of pathogenesis and effective clinical use of new imaging methods. Advanced equine neuroimaging is a specialized field with unique challenges associated with patient size, availability of equipment, using equipment designed for humans, small sample size for various diseases, and issues associated wi...
Hales EN, Esparza C, Peng S, Dahlgren AR, Peterson JM, Miller AD, Finno CJ.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder of unknown etiology. Clinical signs of neurological deficits develop within the first year of life in vitamin E (vitE) deficient horses. A genome-wide association study (GWAS) was carried out using 670,000 SNP markers in 27 case and 42 control Quarter Horses. Two markers, encompassing a 2.5 Mb region on ECA7, were associated with the phenotype (p = 2.05 × 10-7 and 4.72 × 10-6). Within this region, caytaxin (ATCAY) was identified as a candidate gene due to its known role ...
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...
Kamerling SG.The recognition and alleviation of animal pain is a growing veterinary and public concern. Pain can be of an acute or chronic nature with different behavioral manifestations. Physiologically, pain is a dynamic and complex phenomenon that produces changes in the central and autonomic nervous systems as well as in the endocrine system. Horses and other animals appear to possess an endogenous pain-suppressing system involving the brainstem and spinal cord. This system can modulate pain perception and the responses to it. The recently discovered endogenous opioid peptides (endorphins and enkephali...
Poonacha KB, Gregory CR, Vickers ML.The primary lesions of eastern equine encephalomyelitis (EEE) virus infection in the horse are limited to the brain and spinal cord. Intestinal lesions in addition to the changes in the central nervous system were found in a 6-month-old male Tennessee Walking Horse. One week prior to death, this colt was vaccinated for EEE virus, western equine encephalomyelitis virus, influenza virus, equine rhinopneumonitis virus, and tetanus. The clinical signs consisted of ataxia and rear-end weakness, with a body temperature of 102.8 F. Gross lesions consisted of yellowish discoloration, swelling, edema, ...
Manohar M.Regional distribution of brain blood flow (radionuclide labelled 15 microns diameter microspheres) and O2 supply were studied in 11 healthy adult grade ponies at rest and during severe exercise (SE) performed on a treadmill (heart rate = 220 +/- 4 beats X min-1; VO2 = 126 +/- 9 ml X min-1 X kg-1). During SE, the mean aortic pressure increased to 169 +/- 4 mm Hg and the pHa, PaCO2 and PaO2 were 7.213 +/- 0.010, 30 +/- 1 mm Hg and 85 +/- 4 mm Hg, respectively. The hemoglobin concentration increased by 59.6% with SE. Whereas blood flow increased in the cerebellar gray matter (96%), pons (39.5%) a...
